The Bum Steer

[Grub]

I've been watching and reading all the countersteering threads of late and someone's comment "... if you're getting around corners, then you must be coutersteering, can't be done otherwise ..." has prompted me to post a counter-view on counter-steering.

I believe the countersteer that initiates the turn is a bad substitute for poor body position and technique. Hence "The Bum Steer". A turn that is initiated by loading up the "inside bum cheek" does not need counter steering input. Before the howls of Indignation and Outrage gather volume, I do agree that you can use small countersteering adjustments. I just don't agree that it is the only way to initiatre a turn ... back to The Bum Steer.

Watch the top racers, watch the best of them Casey Stoner. Their bodies are on the inside of the bike before they tip in for the corner. In other words, they have loaded up the inside bum cheek and their weight is on the inside of the bike. They are pushing the bars up to hold the bike straight waiting for the tip in. It is poised like a cat and being help up from falling into the corner. As soon as the tip in point is reached, the arms are relaxed and the bike falls into the corner using the weight of the rider. Power is applied to hold it from falling too far thus getting the power down early and the bike under perfect control for driving out of the turn.

Think about the dynamics of this. The counter-steer is using gyroscopic precession to apply a directional force from the application of opposing forces. Doing so unsettles the bikle, you are applying a side-load to the front tyre that doesn't need to be there. The Bum Steer on the other hand is simply letting the bike fall into a position to cut the corner in a totally natural way. All the forces are acting in unision and towards the apex of the corner. If it didn't work, racers wouldn't be using it (watch the MotoGP slow motions to see it in action).

So, how does this apply to the road. Well I've been using the technique for a year and perfected it on my daily runs over Paekakariki Hill Rd - there's not a better test.

On the road it's not about getting off your seat (but I do that too), it's just about leaning your shoulders to the inside just a fraction as you approach the corner. This loads up the inside bum cheek. When you feel the apex has arrived (and with this technique you can go in much deeper) all you have to do is pull the bike down with you. It's fluid, very quick and brilliantly confidence-building.

The counter-steer by its very nature tips the bike into the corner but leaves the rider upright with the outside bum cheek loaded up! This puts the rider's weight in a place where it is trying to stand the bike up while everything else is trying to get around the corner. It just can't be right.

Again, this is not a Ban Countersteering message. I use it all the time for small adjustments and positioning but I truely believe it is a dangerous practice for tipping into corners - there's too much physics working against the natural dynamics of the bike. You can tell the obsessive counter-steerers, they're the ones who look like motorcrossers when you're following them on the road - body upright while they push the bike down in a desperate attempt to carver the corner.

I post this because I am genuinely worried about people training themselves to use unbalanced and contradictory forces to get them into a corner - a process which naturally unsettles a bike.

Several sacred cows have been harmed in the preparation of this message.

Sticks and stones may break my bones but green bling will never hurt me

[quallman1234]

Never liked the Counter-Steer tip in technique, Totally agreed that a little bit of inside force feels a lot more confident verus Tip in by pushing at the bars.

A mixture works the charm.

You going to give bucketering a go on the Nadsty bucket?

[HDTboy]

Are you trying to say that people racing don't actively countersteer?

[Grub]

Are you trying to say that people racing don't actively countersteer?

No, not at all but watch the way they approach the corner and tip in, it is not by countersteering and that's what some people are being told is the only way to turn into a corner. The countersteer tip-in leaves the bike leaning and the rider upright.

[HDTboy]

Countersteering, and the no bullshit bike (http://thekneeslider.com/archives/2007/10/09/motorcycle-countersteering-and-the-no-bs-bike/)

[HDTboy]

No, not at all but watch the way they approach the corner and tip in, it is not by countersteering and that's what some people are being told is the only way to turn into a corner.

It is. The funny thing is that you are doing it when you shift your weight. to keep the bike going straight, you now need to countersteer the opposite way to where your weight is. As soon as you get to the corner, you align your hands with your shoulders, which are cocked in the direction of the corner, viola you're countersteering without knowing it

[HDTboy]

Ixion (http://www.kiwibiker.co.nz/forums/showthread.php?t=12950&highlight=countersteer) did some research

[kiwibryn]

Damn.. so the fact I use body english AND counter-steer makes me... what?
I use both in harmony, the body english and the counter into, during and out... It is the technique I learned to use before I knew what it was called. If I need to tighten the corner I lean harder and tap the front brake. The only bins I've had have been through foreign objects, oil slicks or (once) seized motor.

[Grub]

I'm fully aware this is going to fall into a blind catholic vs protestant type slanging session. All I ask is that people don't blindly defend or promote one point of view without discussing the physics of the alternatives.

Also take the time to look at gyroscopic precession and understand what it is. That act of applying the coutersteering force to the bars applies an equal and opposite force at 90deg to the input point. These are significant forces.

[HDTboy]

Damn.. so the fact I use body english AND counter-steer makes me... what?
I use both in harmony, the body english and the counter into, during and out... It is the technique I learned to use before I knew what it was called. If I need to tighten the corner I lean harder and tap the front brake. The only bins I've had have been through foreign objects, oil slicks or (once) seized motor.

That would make you as normal as the other 70% of motorcyclists who pay attention to the control inputs they are making.
I've had a few crashes, one thing I've learnt is not to use the front brake to tighten my line, more gas does it better.

[Grub]

Damn.. so the fact I use body english AND counter-steer makes me... what?
I use both in harmony, the body english and the counter into, during and out... It is the technique I learned to use before I knew what it was called. If I need to tighten the corner I lean harder and tap the front brake. The only bins I've had have been through foreign objects, oil slicks or (once) seized motor.

And I would say ... that's the perfect answer! You're doing what feels right, balances the bike and comes instinctively.

Bling awarded :)

[HDTboy]

I'm fully aware this is going to fall into a blind catholic vs protestant type slanging session. All I ask is that people don't blindly defend or promote one point of view without discussing the physics of the alternatives.

Also take the time to look at gyroscopic precession and understand what it is. That act of applying the coutersteering force to the bars applies an equal and opposite force at 90deg to the input point. These are significant forces.

I''m not in it for the religion. If you read the link with Ixion's name, you'll realise that you do actually countersteer too. Just because you don't notice it, doesn't mean it's not happening.

[kiwibryn]

That would make you as normal as the other 70% of motorcyclists who pay attention to the control inputs they are making.
I've had a few crashes, one thing I've learnt is not to use the front brake to tighten my line, more gas does it better.

Oh ok, thanx for the tip... mind you, there isn't a lot of grunt in a CX and I am usually halfway through when I realise I might have been going a little hot in too high a gear... still, so far, no stack.. (crosses fingers and looks inncent):D

[Grub]

I''m not in it for the religion, If you read the link with Ixion's name, you'll realise that you do actually countersteer too. Just because you don't notice it, doesn't mean it's not happening.

Read the original post. It says I do use and recommends using countersteer.

This discussion is about people who use it as their only means of tipping into corners and particularly the thread about someone desperately trying to use it because someone has said it is the only way! Bad bad bad.

There two people on the Wellingtn Wednesday rides who look both rediculous and dangerous with their extreme countersteering flicks. It's scary.

[Grub]

I am usually halfway through when I realise I might have been going a little hot in too high a gear

Because you are already using 'body english' your shoulders will already be on the inside of the bike and the weight will be on yer inside cheek. If you get into the position of a tightening line, just relax your elbows & shoulders a little more and the bike will tuck in nicely with a wee touch of power. It's a beautiful feeling

[HDTboy]

How far do you think you could go using your bum steer technique if I welded up the steering head on your bike? Assuming you only countersteer to trim the turn as indicated in the first post.

[Ixion]

The counter-steer by its very nature tips the bike into the corner but leaves the rider upright with the outside bum cheek loaded up! This puts the rider's weight in a place where it is trying to stand the bike up while everything else is trying to get around the corner. It just can't be right.


Eh? That's not right Left corner, shove left shoulder forward , weight moves toward left , y' body will roll (insomuch as it moves at all) onto the left cheek, not right. And vice versa.

You CAN turn a bike without countersteering, but it's of very limited practicality .

I learnt to ride before anybody had ever heard of countersteering.

And then discovered , years later, that it was just a lot of talk about what we had alwasy done.

Try the test and see. Hold the bars just with a finger and thumb. Like pinching the grips. so the only thing on each grip is the tip of you long finger and the tip of your thumb. That way you'll be aware of any inputs you make into the bars. Now try going round a few corners (it works fine).

Pay attention to the pressures on those finger tips. See if you cna corner without any pressure on the finger tips. And if you are pressing, which way.

[Grub]

How far do you think you could go using your bum steer technique if I welded up the steering head on your bike? Assuming you only countersteer to trim the turn as indicated in the first post.

Do you know anything about the design of a bike? Steering head angle? Trail?

[HDTboy]

The counter-steer by its very nature tips the bike into the corner but leaves the rider upright with the outside bum cheek loaded up! This puts the rider's weight in a place where it is trying to stand the bike up while everything else is trying to get around the corner. It just can't be right.

I think I may see the problem. it seems that people are using "countersteering" as an excuse for poor body positioning, and they're doing the old pillion trick of trying to sit upright rather than leaning with the bike.

Edit: I know a little about bike design

[Grub]

Try the test and see. Hold the bars just with a finger and thumb. Like pinching the grips. so the only thing on each grip is the tip of you long finger and the tip of your thumb. That way you'll be aware of any inputs you make into the bars. Now try going round a few corners (it works fine).

Not disputing what countersteering is or that input on the bar makes the bike go the other way. Talking about cornering.

If countersteering is the only way a bike turns then it would be impossible for Stoner or Rossi to go around the track with their arms in the air - which they do. "look ma, no hands" ... I wonder how they do that? Body weight? Leaning?

[jrandom]

Several sacred cows...

Don't you mean steers?

[Forest]

Countersteering, and the no bullshit bike (http://thekneeslider.com/archives/2007/10/09/motorcycle-countersteering-and-the-no-bs-bike/)

That's awesome.

[Devil]

Errr as for the racer's shifting their arse off the seat BEFORE the corner... from what I understand thats what you should be doing instead of making that kind of movement when you're already committed to the corner, therefore potentially unsettling the bike. Your bike is at it's most stable without you, remember...

[Nasty]

Whats really amazing is that I was told that countersteering is a great way to get out of the shit. There is a piece of something on the road and you need to get around it ... you are in the middle of the courner and you need to adjust your position .. these are circumstances where countersteering is perfect. No secret formula .... the countersteer is about leaning the bike over ... to get around things or stuff .... hmmm off to think some more.

[Bass]

Think about the dynamics of this. The counter-steer is using gyroscopic precession to apply a directional force from the application of opposing forces.

I am about to deal to another sacred cow.
I too believed that countersteering worked because of gyroscopic precession.
However, about 18 months ago there was a thread in here that argued this quite vehemently (can't find it at the moment). Anyway, the whole thing was settled when someone quoted an article concerning a guy in the states a couple of years back, who built a bike that had counter-rotating wheels within the normal ones. This, of course, had the effect of cancelling out any gyroscopic effects at all.
He found that the bike handled pretty much as any bike does, i.e. that counter steering still worked and so gyroscopic forces (which do explain the phenomenon) are not the major reason for it.
The conclusion reached was that if (for example) one wishes to turn left and so counter steers to the right. The tyre contact patch moves right and the bike rolls about its own centre of mass and so leans to the left.
Further, for reasons that I can't remember, precession does make some contribution to standing the bike up again when exiting the corner. I presume it has something to do with acceleration.
I shall continue hunting for the thread that I mentioned.

[MSTRS]

It is very simple...riding a bike efficiently is a whole body experience.
Shift of shoulder angle, bum and/or body to one side, weighting pegs, pushing with a knee on the tank, nudging of bars....
The more of these that you combine, the better the result will be.
It is all countersteering to some extent. Obviously the most noticeable technique is the push/pull on the bars, so that is what most do or are taught to do. The other components singly or together do not create enough turn force to be effective in the tight stuff, but will be a thing of beauty in long flowing corners that do not require sharp transitions. For that, you need the bars...

[hellnback]

I've been watching and reading all the countersteering threads of late and someone's comment "... if you're getting around corners, then you must be coutersteering, can't be done otherwise ..." has prompted me to post a counter-view on counter-steering....... blah blah blah
I post this because I am genuinely worried about people training themselves to use unbalanced and contradictory forces to get them into a corner - a process which naturally unsettles a bike.

Several sacred cows have been harmed in the preparation of this message.

Sticks and stones may break my bones but green bling will never hurt me
So basically all your saying is "lean off bike whilst countersteering"

[mowgli]

Think about the dynamics of this. The counter-steer is using gyroscopic precession to apply a directional force from the application of opposing forces. Doing so unsettles the bikle, you are applying a side-load to the front tyre that doesn't need to be there. The Bum Steer on the other hand is simply letting the bike fall into a position to cut the corner in a totally natural way. All the forces are acting in unision and towards the apex of the corner. If it didn't work, racers wouldn't be using it (watch the MotoGP slow motions to see it in action).

You're missing an important point about gyroscopic precession. The bars aren't the only way to induce precession in front tyre. The unbalanced force of your bum on the inside of the turn will indeed apply a force to the inside top of the front tyre as if to lean it into the corner. Due to precession that force acts instead to turn the front tyre into the corner without leaning the bike.

In essence you're using weight shift instead of lean to balance the cornering forces. This will work at slow speeds but at normal speeds you need to lean the bike over and simply shifting your weight won't work. At high speeds when you've reached the lean limit of the bike then you must use weight to balance the forces.

I think this may be where you're getting confused with your racer example. It's easier for them to move their weight before entering the corner to avoid any major shifts mid-corner that might unsettle the bike. I recall a racer on here saying that between two turns on one track he needed all his strength to push on the bars to get from leaning all the way over one way to all the way over on the other side. I'll bet his bum was off the seat as well.

Of course you may be counter steering without realising when you shift your weight because you may naturally be pulling a little on the outside handle bar.

In general I find it much more comfortable at normal speeds to corner simply by keeping my bum on the seat and leaning the bike over into the turn. I do this by counter steering. So I don't buy your bum steer idea. Thanks though because I found it interesting thinking though the physics of it.

[skelstar]

Not sure what this is going to achieve really. You guys won't come to a consensus (you rarely do), the bike/you arrangement is still going to behave the same, you're still going to ride just as well, and the usual culprits will litter the discussion with sexual innuendo.

I find it pays not to think too hard about this kind of thing. I like to know when my tyres are up to temp, where my head is pointing and if the rubber is good. End of story.

[MSTRS]

Not sure what this is going to achieve really. You guys won't come to a consensus (you rarely do), the bike/you arrangement is still going to behave the same, you're still going to ride just as well, and the usual culprits will litter the discussion with sexual innuendo.

I find it pays not to think too hard about this kind of thing. I like to know when my tyres are up to temp, where my head is pointing and if the rubber is good. End of story.

Right on all counts.
Except in bold...a lot of thinking must go into riding a bike. Until your technique becomes automatic, that is. Then your brain is freed-up to consider stuff that hasn't reached you yet. This is why people who have ridden for years seldom bin.

[Mikkel]

I am about to deal to another sacred cow.
I too believed that countersteering worked because of gyroscopic precession.
However, about 18 months ago there was a thread in here that argued this quite vehemently (can't find it at the moment). Anyway, the whole thing was settled when someone quoted an article concerning a guy in the states a couple of years back, who built a bike that had counter-rotating wheels within the normal ones. This, of course, had the effect of cancelling out any gyroscopic effects at all.
He found that the bike handled pretty much as any bike does, i.e. that counter steering still worked and so gyroscopic forces (which do explain the phenomenon) are not the major reason for it.
The conclusion reached was that if (for example) one wishes to turn left and so counter steers to the right. The tyre contact patch moves right and the bike rolls about its own centre of mass and so leans to the left.
Further, for reasons that I can't remember, precession does make some contribution to standing the bike up again when exiting the corner. I presume it has something to do with acceleration.
I shall continue hunting for the thread that I mentioned.

If he had done his job of countering the angular momentum of the wheels properly I'm sure he'd have gotten a rather different result.

If you construct a bike with rotating counterweights that exactly out-balances the angular momentum you will find that the bike - at ALL speeds - have exactly as much balance as it has when stationary. I.e. not a whole lot TBQFH!
So if he claims that he found the bike to be riding quite like a normal bike he hasn't managed to cancel out the gyroscopic forces at all - as such his conclusions are utterly inconsequential!

[skelstar]

Right on all counts.
Except in bold...a lot of thinking must go into riding a bike. Until your technique becomes automatic...
So why don't they teach this 'bumsteer'/countersteer blah blah theory at BHST unless it was already automatic. First time I'd heard the counter-steer thing was probably a month or two after I'd started riding. So maybe 5000kms into my riding 'career'.

Quite honestly I think its just an opportunity for people to post big words.

[Ocean1]

I've been watching and reading all the countersteering threads of late and someone's comment "... if you're getting around corners, then you must be coutersteering, can't be done otherwise ..." has prompted me to post a counter-view on counter-steering.

Taking my name in vain dude?

The comment remains valid, unless you’re talking about a slow sweeper any “normal” traverse of a corner on a bike requires countersteering. I didn’t say that was the only input required.

And you’re right, the no-lean quick flick technique is dirt related. As you say, it puts the bike down and not the rider, exactly correct for your typical dirt bike at any sort of speed. The only time I’d do that on the Buell would be if the other requirement for that technique could be met: break the back loose. So, on the dirt, or gravel.

My reactions are still dirty, a thing that may one day get me into trouble if I let my reactions over-ride my brain. I’m very aware of that, but there’s a hell of a lot of people who ride very different types of bike regularly and quite successfully modify their style to suit.


Think about the dynamics of this. The counter-steer is using gyroscopic precession to apply a directional force from the application of opposing forces. Doing so unsettles the bikle, you are applying a side-load to the front tyre that doesn't need to be there. The Bum Steer on the other hand is simply letting the bike fall into a position to cut the corner in a totally natural way. All the forces are acting in unision and towards the apex of the corner. If it didn't work, racers wouldn't be using it (watch the MotoGP slow motions to see it in action).


No it’s not. Sure, gyroscopic precession stabilises the bike’s attitude in direct proportion to speed, and any steering force applied to the bars has to overcome that. And yes, any steering input produces lateral force at the contact patch, but that force isn’t derived from or related to gyroscopic precession. What’s more that lateral force isn’t high, only on the slickest surfaces have I ever had initial steering inputs result in a wash-out, it’s a far smaller traction issue than that required to navigate the corner itself.

Like almost all of us you would have tried cornering with no steering input, it’s not that difficult, just sluggish. I’m willing to bet you failed the first time, grabbed for the bars half way through. You probably noticed that it takes longer to initiate the turn, and that it takes far more “counterlean” to stand the bike up again than it did to get it to fall in.

The fact is that all countersteering is doing is placing the bike outside your body mass, exactly the same thing you achieve by leaning your body in, but far faster, and with more control. The reason it’s faster is because any lateral movement of your body weight alone produces an initial equal and opposite reaction in the bike, cancelling much of the effect.

Fast dudes do pre-lean, but they also give the bars a savage tweak to initiate the turn itself. So much so that sometimes they bend the bloody bars. I’m not suggesting taking inputs to such an extreme on the road, but it’s a mistake to suggest that racers use predominantly body lean to navigate corners.

One thing we agree on, a good rider knows all of the available inputs possible to change the attitude of a bike, and uses them. Whether he knows exactly which input produces which effect depends on how much time he’s spent experimenting. The dirt’s a great place to do that. The road ain’t.


I am about to deal to another sacred cow.
I too believed that countersteering worked because of gyroscopic precession.
However, about 18 months ago there was a thread in here that argued this quite vehemently (can't find it at the moment). Anyway, the whole thing was settled when someone quoted an article concerning a guy in the states a couple of years back, who built a bike that had counter-rotating wheels within the normal ones. This, of course, had the effect of cancelling out any gyroscopic effects at all.
He found that the bike handled pretty much as any bike does, i.e. that counter steering still worked and so gyroscopic forces (which do explain the phenomenon) are not the major reason for it.
The conclusion reached was that if (for example) one wishes to turn left and so counter steers to the right. The tyre contact patch moves right and the bike rolls about its own centre of mass and so leans to the left.
Further, for reasons that I can't remember, precession does make some contribution to standing the bike up again when exiting the corner. I presume it has something to do with acceleration.
I shall continue hunting for the thread that I mentioned.

Interesting. And surprisingly it agrees with the above.


Not sure what this is going to achieve really. You guys won't come to a consensus (you rarely do), the bike/you arrangement is still going to behave the same, you're still going to ride just as well, and the usual culprits will litter the discussion with sexual innuendo.

I find it pays not to think too hard about this kind of thing. I like to know when my tyres are up to temp, where my head is pointing and if the rubber is good. End of story.

If you asked a real natural racer exactly what forces apply to which control inputs he uses he probably couldn’t tell you. Some of us are not naturally that talented dude, we like to pick a process to pieces so we can understand it better. That, and we just like to argue.

[MSTRS]

So why don't they teach this 'bumsteer'/countersteer blah blah theory at BHST unless it was already automatic. First time I'd heard the counter-steer thing was probably a month or two after I'd started riding. So maybe 5000kms into my riding 'career'.

Quite honestly I think its just an opportunity for people to post big words.

BHS is just that...Basic Handling. The push (or pull) method of steering is the most basic and effective way of changing a bike's direction of travel. Undeniable.
The other techniques can be learned with experience, experimenting or at an Advanced course.

[Ocean1]

Right on all counts.
Except in bold...a lot of thinking must go into riding a bike. Until your technique becomes automatic, that is. Then your brain is freed-up to consider stuff that hasn't reached you yet. This is why people who have ridden for years seldom bin.

Think it's usually the other way around. Most people don't think much about how they manage a pushbike when they first learn, it's only when it becomes automatic that they start to think "why".

[Badjelly]

I believe the countersteer that initiates the turn is a bad substitute for poor body position and technique. Hence "The Bum Steer". A turn that is initiated by loading up the "inside bum cheek" does not need counter steering input. Before the howls of Indignation and Outrage gather volume, I do agree that you can use small countersteering adjustments. I just don't agree that it is the only way to initiatre a turn ... back to The Bum Steer.

Interesting stuff, Grub. You talk about Casey Stoner, but Casey and his MotoGP pals go through corners hanging off the inside of the bike. I don't see people do that on the road, certainly not so much. I (think) I go through corners with my torso pretty much on the axis of the bike, and my head tilted outwards to keep it roughly horizontal. Are you suggesting I should move my body to the inside?

I agree that riders can and should change their weight distribution on the bike as they enter corners, but I suspect that it's the handlebar inputs that actually initiate the turn.

Like I said, interesting stuff...

[Badjelly]

Most people don't think much about how they manage a pushbike when they first learn, it's only when it becomes automatic that they start to think "why".
And some never think why, in fact they actively resist it. Which is fair enough, but some people (I'm one) like to analyse what they do.

[MSTRS]

Think it's usually the other way around. Most people don't think much about how they manage a pushbike when they first learn, it's only when it becomes automatic that they start to think "why".

Knowing 'why' may require thinking, but in all likelihood only as much thinking as is needed to track down someone who can tell you why. A lot of us have no real interest in the why, just to know it works is enough. And I stand by what I said...the less 'thinking' one has to do about the mechanics of guiding one's machine, the better able one is to plan ahead. Therefore avoiding hazards more easily.

[Ocean1]

If he had done his job of countering the angular momentum of the wheels properly I'm sure he'd have gotten a rather different result.

If you construct a bike with rotating counterweights that exactly out-balances the angular momentum you will find that the bike - at ALL speeds - have exactly as much balance as it has when stationary. I.e. not a whole lot TBQFH!
So if he claims that he found the bike to be riding quite like a normal bike he hasn't managed to cancel out the gyroscopic forces at all - as such his conclusions are utterly inconsequential!

Not true, there's another huge difference between a stationary and moving bike when it come to possible control inputs. YOU"RE MOVING, any change in steering input is effective because it's possible to change the contact patch.

[Ocean1]

Knowing 'why' may require thinking, but in all likelihood only as much thinking as is needed to track down someone you can tell you why. A lot of us have no real interest in the why, just to know it works is enough. And I stand by what I said...the less 'thinking' one has to do about the mechanics of guiding one's machine, the better able one is to plan ahead. Therefore avoiding hazards more easily.

For me, when riding, (rather than "experimenting") it's two completely different exercises. So yeah, the execution does not require knowledge, we're saying the same thing.

[Badjelly]

Quite honestly I think its just an opportunity for people to post big words.

I disagree, though I can see why you would think that. It's a bit like wine criticism: all that "hint of lychees" and "soft tannins with a lingering finish" stuff sounds like waffle, and to some extent it is, but bugger me, some wines really do taste like that!

Ocean1's post a few messages back has clarified several things for me and is, in my opinion, a clear demonstration that it's not just big words.

[Mikkel]

Not true, there's another huge difference between a stationary and moving bike when it come to possible control inputs. YOU"RE MOVING, any change in steering input is effective because it's possible to change the contact patch.

Either you didn't read or you didn't understand my post. If it's the latter case I could suggest starting out here: Classical Mechanics (http://en.wikipedia.org/wiki/Classical_mechanics).

[MSTRS]

... So yeah, the execution does not require knowledge, we're saying the same thing.

Hope so...coming from the angle of a relative newby, they are constantly and consciously brain-guiding their machine. How and why it works is not an issue for them at that point, just the fact that it does work. However, it doesn't happen 'automatically' until a sufficient amount of practice has occurred, hence my take on the 'thinking' bit. Once the inputs are happening more-or-less without conscious thought, then the rider may start to think 'why does it work?'. Doing this at this point is a good thing, because the rider is then in a position to make a quantum leap in their abilities to react to various situations that present. Experienced riders are not necessarily 'fast' but will be better equipped on the roads to survive. And in all likelihood be faster on average through being consistent.

[Ocean1]

Either you didn't read or you didn't understand my post. If it's the latter case I could suggest starting out here: Classical Mechanics (http://en.wikipedia.org/wiki/Classical_mechanics).

Oh I'm sure you can think of a third alternative dude. :bleh:

[Mikkel]

Oh I'm sure you can think of a third alternative dude. :bleh:

You're pulling my leg. I see ;)

[Deano]

Just because you don't notice it, doesn't mean it's not happening.

And on that note - just because you can't see the GP stars doing it, doesn't mean they aren't.

I would go so far as to say that in the tight flip flop chicanes, these guys are literally wrenching the bars to change direction in time.

[Ocean1]

You're pulling my leg. I see ;)

At what speed do you consider a bike to behave “normally” with regard to control inputs. In other words using other than lateral body movement alone to maintain ballance and affect course?

How much vertically stabilising force do you suppose gyroscopic precession is contributing at that speed?


And on that note - just because you can't see the GP stars doing it, doesn't mean they aren't.

I would go so far as to say that in the tight flip flop chicanes, these guys are literally wrenching the bars to change direction in time.

And taking advantage of the vertical kick between turns to shift their arse? Bloody difficult to do once you’re into the corner with under much higher G.

[James Deuce]

You can't turn a bike without a counter steering input at the bars.

"Body English" for steering is pure and simple rubbish. Next time you want to steer into a turn without using counter steering, take your hands off the bars, shift your bum in the seat and we'll record your howls of dismay as Rotational Momentum and inertia keep the bike going straight ahead. As your speed decays, there will be a point where gravity overwhelms rotational momentum and inertia and the bike will flop from side to side if you move your weight and you'll turn just before you fall over.

[Steam]

You can't turn a bike without a counter steering input at the bars.
"Body English" for steering is pure and simple rubbish.

What??? Try it next time you are in a safe deserted place, take your hands off the handlebars and just shift your weight slightly. I swear it works. Doesn't it?:scratch:

[Forest]

I am about to deal to another sacred cow.
I too believed that countersteering worked because of gyroscopic precession.
However, about 18 months ago there was a thread in here that argued this quite vehemently (can't find it at the moment). Anyway, the whole thing was settled when someone quoted an article concerning a guy in the states a couple of years back, who built a bike that had counter-rotating wheels within the normal ones. This, of course, had the effect of cancelling out any gyroscopic effects at all.
He found that the bike handled pretty much as any bike does, i.e. that counter steering still worked and so gyroscopic forces (which do explain the phenomenon) are not the major reason for it.
The conclusion reached was that if (for example) one wishes to turn left and so counter steers to the right. The tyre contact patch moves right and the bike rolls about its own centre of mass and so leans to the left.
Further, for reasons that I can't remember, precession does make some contribution to standing the bike up again when exiting the corner. I presume it has something to do with acceleration.
I shall continue hunting for the thread that I mentioned.


I think the web-site you are looking for is:

http://www.reverserotatingrotors.com/

Here is a link to the patent:

http://www.google.com/patents?vid=USPAT6918467

[MSTRS]

Exactly, Jim2. All the weight changing in the world will only make the process smoother and more stable, it is the bar work that really counts.
Try riding in a straight line when you've been working the bar heavily :shifty::laugh:

[Sully60]

You can't turn a bike without a counter steering input at the bars.

"Body English" for steering is pure and simple rubbish. Next time you want to steer into a turn without using counter steering, take your hands off the bars. shift your bum in the seat and we'll record your howls of dismay as Rotational Momentum and inertia keep the bike going straight ahead. As your speed decays, there will be a point where gravity overwhelms rotational momentum and inertia and the bike will flop from side to side if you move your weight and you'll turn just before you fall over.

How does that explain wheelies around corners or circular wheelies were the front wheel has no contact with the ground?
Off the general direction of topic but I'd like to hear your explanation.

Edit: sorry for crappy picture, but usefull to expalin my point

[Forest]

How does that explain wheelies around corners or circular wheelies were the front wheel has no contact with the ground?
Off the general direction of topic but I'd like to hear your explanation.

Edit: sorry for crappy picture, but usefull to expalin my point

When both wheels are on the ground, the stability comes from the trail of the front wheel.

Basically the friction of the front tyre behind the steering axis causes the front tyre to "self correct".

Here is an article that explains things much better than I can.

http://wellyouneednot.blogspot.com/2006/02/counterintuitive.html

When you lift the front tyre during a wheelie there is no longer any trail or correcting forces on the front wheel. So the only way you can steer is by changing your center of gravity i.e. moving your body weight.

[vifferman]

How does that explain wheelies around corners or circular wheelies were the front wheel has no contact with the ground?
Off the general direction of topic but I'd like to hear your explanation.
That's a little different - the steering is accomplished by a controlled fall (and recovery) in the direction you're steering in. You're moving the C of G towards the intended direction of travel.

[Sully60]

When you lift the front tyre during a wheelie there is no longer any trail or correcting forces on the front wheel. So the only way you can steer is by changing your center of gravity i.e. moving your body weight.


You're moving the C of G towards the intended direction of travel.



Which was exactly my point, I cannot countersteer with no front wheel contact but I can alter the direction of the bike.


"Body English" for steering is pure and simple rubbish

For steering/turning alone with no counter steering I agree, but the simple physics are that the rider must make up on average at least a third of the total weight of both rider and machine, and being perched on top of the "lever" moving your weight will influence the direction of the bike.

I think Grubs reference to the racers is maybe a little misguided in this instance, He has made no mention of how the riders distribute their weight with their feet. Although they have there body mass weighted to the inside of the turn most of their weight will be on the outside footpeg, just ask #34 (Kevin Schwantz)

[James Deuce]

Keith Code built a ZX6R to refute the leaning/body weight movement theory of motorcycle steering once and for all.

http://www.superbikeschool.com/news/press-releases/no_bs_bike_release.php

http://www.superbikeschool.com/machinery/no-bs-machine.php

There are a huge range of influences on motorcycle dynamics and they aren't understood very well as a whole. Moments of inertia shift as a bike steers, the effect of gravity on a leaning object changes how it behaves in a corner, the geometry of the forks dictate at what speed counter steering takes over from "normal" steering, braking and acceleration change a bike's chassis geometry in relation to the surface it is traveling on, and so on. But to overcome gyroscopic precession for a two wheeled, tandem in-line vehicle you HAVE to turn a wheel opposite to the direction you want to turn to initiate a lean in that direction.

Distributing your weight changes how the chassis responds to input. To steer you HAVE to countersteer once you are traveling at more than 10-25 kph depending on motorcycle geometry. The faster you go and the more your bike weighs, the greater the force required to initiate a turn. Once the bike has turned the motorcycle will maintain that attitude until another force acts on it to change its attitude.

You need to learn what force you need to make a bike lean to a particular angle when countersteering. This will take a huge amount of stress and guesswork out of your Sunday blats if you can precisely dial up a particular angle of dangle for a given speed and a given turn radius. Racers get really good at this because they get to practice the same corners over and over on a race track. They turn harder and later and spend less time loading suspension up on the way into a turn and as a consequence don't have to lean as far for a give speed.

[Deano]

What??? Try it next time you are in a safe deserted place, take your hands off the handlebars and just shift your weight slightly. I swear it works. Doesn't it?:scratch:


Try going around anything other than a very shallow bend without your hands on the bars.

I can do it down Oakleigh but it takes practice and a lot of body shift - and it is a very shallow bend.

[Deano]

And taking advantage of the vertical kick between turns to shift their arse? Bloody difficult to do once you’re into the corner with under much higher G.

Cycosis beat White Trash at Manfeild (just) - ask Jimmy how much Cycosis moved on his seat.

He will no doubt have moved slightly, but not to the same degree as Jimmy, yet still managed to go as quick, if not quicker through the corners...how did he do this ?

Counter steering.

[Deano]

So the only way you can steer is by changing your center of gravity i.e. moving your body weight.

Pretty sure the guys I know use body weight shift AND turning the bars, especially while the front is still spinning.

[James Deuce]

Exactly. Why waffle about with vague and minor angles of lean for a lot of body weight shift when you can precisely dial up the angle of lean you want through your bars? The faster you go the lesser the amount of lean you will generate for a larger and larger amount of weight shift.

[Mikkel]

At what speed do you consider a bike to behave “normally” with regard to control inputs. In other words using other than lateral body movement alone to maintain ballance and affect course?

How much vertically stabilising force do you suppose gyroscopic precession is contributing at that speed?

You did indeed not read my post I see.

My argument was that the guy who made an attempt at counter-rotating weights to cancel out the gyroscopic effect of the wheels didn't do it properly...

If he had, he would indeed not have been able to ride the bike in a straight line (or most likely not at all)... As such, the conclusions derived from his study of the behaviour of such a bike would be without merit.

It has nothing to do with speed or how the bike reacts to steering input - simply the fact that if you completely eliminate the gyroscopic effect of the bike it's not going to be rideable (at any speed).

[James Deuce]

Which was exactly my point, I cannot countersteer with no front wheel contact but I can alter the direction of the bike.



For steering/turning alone with no counter steering I agree, but the simple physics are that the rider must make up on average at least a third of the total weight of both rider and machine, and being perched on top of the "lever" moving your weight will influence the direction of the bike.

I think Grubs reference to the racers is maybe a little misguided in this instance, He has made no mention of how the riders distribute their weight with their feet. Although they have there body mass weighted to the inside of the turn most of their weight will be on the outside footpeg, just ask #34 (Kevin Schwantz)

The dynamics of a Unicycle are vastly different to a Bicycle. Yes, you WERE countersteering as a kid on a bicycle, but the amount of force to turn a bicycle is tiny compared to the force required to turn a motorcycle 15 to 20 times heavier and 10 to 15 times faster. So tiny it is indistinguishable from the subsequent lean that feels like it was generated by moving your body weight.

[jrandom]

to overcome gyroscopic precession for a two wheeled, tandem in-line vehicle you HAVE to turn a wheel opposite to the direction you want to turn to initiate a lean in that direction... To steer you HAVE to countersteer once you are traveling at more than 10-25 kph depending on motorcycle geometry.

Presumably, the fact that I can steer a bike around corners as it rolls in gear downhill doing 50-60kph with my hands off the bars, using my hips and knees and waving my upper body about, is because gyroscopic precession isn't the be-all and end-all of the matter.

In other words, the bike can still be steered with weight re-distribution only, it's just that as it goes faster, the gyroscopic force gets greater, and eventually the weight redistribution required to steer it without changing the gyroscopic force direction becomes quite high, so it's imperative to push on the handlebars.

I also note that as I steer it by moving my body weight around, the bars naturally flop in a countersteering-like manner. What's the story with that then?

[James Deuce]

Presumably, the fact that I can steer a bike around corners as it rolls in gear downhill doing 50-60kph with my hands off the bars, using my hips and knees and waving my upper body about, is because gyroscopic precession isn't the be-all and end-all of the matter.

In other words, the bike can still be steered with weight re-distribution only, it's just that as it goes faster, the gyroscopic force gets greater, and eventually the weight redistribution required to steer it without changing the gyroscopic force direction becomes quite high, so it's imperative to push on the handlebars.

I also note that as I steer it by moving my body weight around, the bars naturally flop in a countersteering-like manner. What's the story with that then?

Try doing it at 260km/hr.

It depends on the amount of mass required to overcome the force generated by rotational inertia. As you've noticed the bars will turn away from the direction you are travelling

The danger to the myth that counter steering doesn't work and can be ignored is that people will now go out and try to change lanes on the motorway by shifting their weight. You can precisely steer a motorcycle with the bars or you can fuck about try to turn your bike with your knees.

Your choice. I can't see why people would chose imprecision over precision when it is already a dangerous business, riding a motorcycle.

[MSTRS]

I also note that as I steer it by moving my body weight around, the bars naturally flop in a countersteering-like manner. What's the story with that then?

Think of the steering head being a hinge-pin...you are sitting on one half of the hinge...if you push that half in one direction, it's opposite half will turn in the opposing direction. Once the turn is initiated, the front of the bike will fall back into line with the rear and stay there, until you again apply some counter force to change things.
Simple.

[skelstar]

I also note that as I steer it by moving my body weight around, the bars naturally flop in a countersteering-like manner. What's the story with that then?
It'd be the 'impulse' of you shifting your weight that makes it steer. Hinge-like re: MSTRS's post.

I can steer myself all the way down the lower-half of Belmont Hill just with shifting weight (agressively) around... not regularly, just for fun.

[jrandom]

Try doing it at 260km/hr.

Exactly. That's my point. Countersteering isn't the only way to turn a motorcycle. If you hang enough weight off the side, the motorcycle will turn that way. More speed requires more weight or a longer lever, etc. 260kph means that you have to push on the bars, because you simply don't have enough weight or a long enough lever to turn the bike any other way.

By the way, in response to your 'precision' comment, I like to roll down hills in top gear pretending to paddle a canoe with both hands because it looks silly and is fun.

Which is what the whole motorcycling deal is supposed to be about, after all!

You won't catch me not using countersteering on a racetrack, though. (Or while changing lanes on a motorway, for that matter.)

[MSTRS]

It'd be the 'impulse' of you shifting your weight that makes it steer. Hinge-like re: MSTRS's post.

I can steer myself all the way down the lower-half of Belmont Hill just with shifting weight (agressively) around... not regularly, just for fun.

Major Drive? You won't do it on the other roads on the hill...Pomare/Wairere/Park/Hill

[James Deuce]

You're perpetuating the myth that counter steering is pointless, or at best conditional, with your attitude, which means I can't respect that opinion at all. I get vastly more fun from dialling up the correct angle of lean for a given speed and corner radius so I don't have to correct, or I can precisely modify a line, than I ever would from taking my hands of the bars, where the throttle, clutch, and 90% of my braking lives.

[skelstar]

Damn, I meant Kelson Hill. Yeah and I meant upper-half. Heh... post lunchtime.

[Forest]

You did indeed not read my post I see.

My argument was that the guy who made an attempt at counter-rotating weights to cancel out the gyroscopic effect of the wheels didn't do it properly...

If he had, he would indeed not have been able to ride the bike in a straight line (or most likely not at all)... As such, the conclusions derived from his study of the behaviour of such a bike would be without merit.

It has nothing to do with speed or how the bike reacts to steering input - simply the fact that if you completely eliminate the gyroscopic effect of the bike it's not going to be rideable (at any speed).

You should read the article I just linked on trail.

Motorcycle stability comes from trail, not from gyroscopic effects.

[MSTRS]

Presumably, the fact that I can steer a bike around corners as it rolls in gear downhill doing 50-60kph with my hands off the bars, using my hips and knees and waving my upper body about, is because gyroscopic precession isn't the be-all and end-all of the matter.




Try doing it at 260km/hr.




Exactly. That's my point. Countersteering isn't the only way to turn a motorcycle. If you hang enough weight off the side, the motorcycle will turn that way. More speed requires more weight or a longer lever, etc.

The greater the speed that the wheels rotate at, the greater the gyroscopic effect that needs to be offset. Problem with weight-shift alone is that it is too waffly and imprecise to be universally useful. Even at legal, but high, speeds.

[Ixion]

How does that explain wheelies around corners or circular wheelies were the front wheel has no contact with the ground?
Off the general direction of topic but I'd like to hear your explanation.

Edit: sorry for crappy picture, but usefull to expalin my point

The "wheelie" context is actually irrelevant, because you have effectively turned your motorbicycle into a motor unicycle.

That changes things greatly, because you no longer have the bicycle issue of the front and rear wheels needing to follow different arcs.

You steer a unicycle by ackerman angle, like a car. Watch a unicycle rider sometimes , he doesn't corner by leaning over.

One thing that causes confusion is that people believe that leaning a bike over in itself makes it go round a corner. Not so. You can lean bike over until it's handlebars touch the ground, but that in itself will not make it deviate from a straight line.

Try it. Walk beside your bike. Now, lean it over (I suggest toward you), but hold the bars straight ahead. Keep walking. Are you going in a circle? Thought not. It would be quite hard to push the bike to the gas station if it were not so.

Why a bike corners when leaned, is because the countersteering thing works both ways, once you have enough momentum for the gyroscope business to work. Turn the bars , and the bike leans over. Lean the bike over, and the bars turn. In either case what initiates the actual turn is the displacement of the front wheel contact patch.

You can turn without consciously initiating the turn by countersteering. Ride along with a heavy weight on the tank. Now hold the weight out to one side. The bike will lean over because of the offset CoG. That will turn the bars, an initiate a turn. Providing of course the bars are able to turn.

If the bars are locked, you won't turn, no matter how hard you lean. You can test this, I did it once. Tie a rope from each end of the bars back to the saddle tree (works best with wide bars). That should lock the bars so they won't move either way. Now get at the top of a hill and roll down it. Try to turn by leaning over. Won't work. Will hurt.

A good rider can maintain some degree of control by moving weight about in this fashion. Some degree. Sort of.

However, I do agree with the original poster, in that in some cases novices become obsessed with counter steering.

For normal day to day ridsing, no one should need to think about it. The only times you *need* to think "COUNTERSTEER" is if you need to dodge something, or you misjudge a corner and end up in the poo, and need to tighten up hard.

Of course, both those situations may be life and death ones, which is why training and mentoring courses concentrate on them.

[Deano]

I also note that as I steer it by moving my body weight around, the bars naturally flop in a countersteering-like manner. What's the story with that then?

I found the opposite, the bars tend to tip in. This is on a 50km/h downhill gentle curve using body weight shift alone, hands off bars.

[Ixion]

You should read the article I just linked on trail.

Motorcycle stability comes from trail, not from gyroscopic effects.

It's the gyroscopic effect that causes a bike to turn in an arc when leaned over. It's trail that resists that to a greater or lesser degree . More trail,. more resistance to falling over, more stability.

Zero trail (vertical forks) the wheel will tuck under immediately and fall over . Infinite trail (horizontal forks) the bike will never turn. Somewhere in between is a good medium, for varying values of medium

[jrandom]

I found the opposite, the bars tend to tip in. This is on a 50km/h downhill gentle curve using body weight shift alone, hands off bars.

You know... come to think of it, you're quite right.

I hadn't really thought about what the bars did during hands-off steering until now, and got my visualisation round the wrong way.

:Oops:

[MSTRS]

...what initiates the actual turn is the displacement of the front wheel contact patch.....

The crux of the whole discussion. Something you do that causes the contact patch of the front tyre to move off-centre. Assuming the steering head is free to move, the bike will lean and turn in the direction that patch 'moved'.
But still, to move that contact patch quickly and concisely requires input through the bars...
And Deano/Jrandom...there will be a momentary turn of the bars in the opposite direction to the turn, before they turn in line with the direction of that turn.

[jrandom]

You're perpetuating the myth that counter steering is pointless, or at best conditional, with your attitude, which means I can't respect that opinion at all.

Surely nobody of sound mind could interpret my comments to mean that countersteering is either pointless or conditional. Pushing on the bars into a corner is obviously the correct way to steer a motorcycle, and in fact the only way when one is doing anything other than pissing about at low speed.


I get vastly more fun from dialling up the correct angle of lean for a given speed and corner radius so I don't have to correct, or I can precisely modify a line, than I ever would from taking my hands of the bars...

You should try the canoe-paddling trick sometime when you have a pedestrian audience.

:D

[Ocean1]

I can steer a bike around corners as it rolls in gear downhill doing 50-60kph with my hands off the bars, using my hips and knees and waving my upper body about,


It depends on the amount of mass required

<_<


and10stuff

[jrandom]

<_<

Like I keep saying. They're racing pies.

[Ocean1]

You did indeed not read my post I see.

My argument was that the guy who made an attempt at counter-rotating weights to cancel out the gyroscopic effect of the wheels didn't do it properly...

If he had, he would indeed not have been able to ride the bike in a straight line (or most likely not at all)... As such, the conclusions derived from his study of the behaviour of such a bike would be without merit.

It has nothing to do with speed or how the bike reacts to steering input - simply the fact that if you completely eliminate the gyroscopic effect of the bike it's not going to be rideable (at any speed).

And the pushbikes with skis instead of wheels wot you see kids playing on the slopes?

[mowgli]

That's a little different - the steering is accomplished by a controlled fall (and recovery) in the direction you're steering in. You're moving the C of G towards the intended direction of travel.

Not quite. A fall alone won't do it.

The change of direction is caused by the unbalanced side force acting on the tyres. This is caused by a combination of gravity pulling the bike over and momentum pulling it upright. Lean angle and speed are the variables that determine the magnitude of the unbalanced force and therefore the rate of turn.

Edit: road camber will also add/subtract to the side force created.

But for most of us we think I wanna go left and the bike goes left.

[Ocean1]

Like I keep saying. They're racing pies.

And cake, don't fergit the cake.

I haven't.

Bastard.

[MSTRS]

Not quite. A fall alone won't do it.

The change of direction is caused by the unbalanced side force acting on the tyres. This is caused by a combination of gravity pulling the bike over and momentum pulling it upright. Lean angle and speed are the variables that determine the magnitude of the unbalanced force and therefore the rate of turn.

But for most of us we think I wanna go left and the bike goes left.

Aggghhhh...there's that word 'thinking' again!!

[jrandom]

This is caused by a combination of gravity pulling the bike over and momentum pulling it upright. Lean angle and speed are the variables that determine the magnitude of the unbalanced force...

You utter muppet; all you did there was rephrase vifferman's post.

[jrandom]

Aggghhhh...there's that word 'thinking' again!!

Cogito ergo inclino?

[Ixion]

The crux of the whole discussion. Something you do that causes the contact patch of the front tyre to move off-centre. Assuming the steering head is free to move, the bike will lean and turn in the direction that patch 'moved'.
But still, to move that contact patch quickly and concisely requires input through the bars...
And Deano/Jrandom...there will be a momentary turn of the bars in the opposite direction to the turn, before they turn in line with the direction of that turn.

Yes. You can move it whatever way, but USUALLY the best way , and the most controllable, is to move the handlebars. That , after all, is what they are there for. And since discussions about how to steer a motorcycle usually are focused on beginners (if you've been riding for years, presumably you've found out how to go round corners, one way or another. Or have a VERY long driveway). And it's a good ideea to give them the simplest safest most reliable method.

And the reason , ultimately, that moving the front wheel contact patch causes you to go in an arc, is that the front wheel is trying to catch up with the rear wheel , since both are attempting to follow the path of the centre of mass, but can't because of the frame holding them apart .

[Mikkel]

You should read the article I just linked on trail.

Motorcycle stability comes from trail, not from gyroscopic effects.

With all due respect. That is a load of rubbish. I'm not going to say that the trail doesn't play a role in stability - because it does. But the actual balance that keep your bike upright while you're riding stems from the rotational mass!
The trail is what determins how easily that balance is upset - easily upset means sharp turn-in and high maneouverability but a bit jerky and unsettled for cruising...


Now, I apologise for my poor paint skills but..., here's a sketch of the force vectors in a leaned over motorcycle. Fn is the normal force proviceded by the tyres (it goes from the contact patches through the centre of mass!), Fg is the gravitational forces working on the centre of mass (COM - the blue spot) and F1 and F2 are composants of the normal force. F1 will have the same magnitude as Fg - otherwise the bike either starts sinking into the tarmac or starts levitating. The lean angle then quite simply dictates how big you make F2 - or how much cornering force you have available. Now, if you shift your COM of the axis of the bike by shifting your weight off the saddle it is easy to see how you can get the normal force vector on a higher degree of lean while keeping the bike upright.
This is the basic force balance. All the frustrating details such as steering geometry and such you can leave out...

[007XX]

And cake, don't fergit the cake.

I haven't.

Bastard.

Oh FFS...would you just let it go?!? :rofl:


Aggghhhh...there's that word 'thinking' again!!

Just strained a braincell there, did ya? :dodge:

What I don't understand (and of course, cos I'm just a poor little bird brain female, yaddi yadda...blah, blah) is why you guys keep on arguing about something you all fundamentally seem to agree on in principal?

Secondly, how is you brainiacs flinging scientific terms at each other going to help your average, 100 IQ, and probably still needing training wheels Newbie...And yes, I mean me mostly :p

So speak in goddarn lemens terms please...:angry2:

Ok, I'll go and have a cup of tea and a lie down now...:eek5::wacko:

[Forest]

With all due respect. That is a load of rubbish. I'm not going to say that the trail doesn't play a role in stability - because it does. But the actual balance that keep your bike upright while you're riding stems from the rotational mass!
The trail is what determins how easily that balance is upset - easily upset means sharp turn-in and high maneouverability but a bit jerky and unsettled for cruising...

No it doesn't. The bikes with counter-rotating weights show this isn't true.

Stability derives from trail. If you don't accept this, try riding a bike with no trail and report back to us on the high speed stability.



Now, I apologise for my poor paint skills but..., here's a sketch of the force vectors in a leaned over motorcycle. Fn is the normal force proviceded by the tyres (it goes from the contact patches through the centre of mass!), Fg is the gravitational forces working on the centre of mass (COM - the blue spot) and F1 and F2 are composants of the normal force. F1 will have the same magnitude as Fg - otherwise the bike either starts sinking into the tarmac or starts levitating. The lean angle then quite simply dictates how big you make F2 - or how much cornering force you have available. Now, if you shift your COM of the axis of the bike by shifting your weight off the saddle it is easy to see how you can get the normal force vector on a higher degree of lean while keeping the bike upright.
This is the basic force balance. All the frustrating details such as steering geometry and such you can leave out...

Notice how there are no vectors for gyroscopic forces in your diagram?

Funny that.

[Badjelly]

What I don't understand (and of course, cos I'm just a poor little bird brain female, yaddi yadda...blah, blah) is why you guys keep on arguing about something you all fundamentally seem to agree on in principal?

Curiously enough, the only thing that went through the mind of the bowl of petunias as it fell was, "Oh no, not again". Many people have speculated that if we knew exactly why the bowl of petunias had thought that we would know a lot more about the nature of the universe than we do now.

[Mikkel]

No it doesn't. The bikes with counter-rotating weights show this isn't true.

Stability derives from trail. If you don't accept this, try riding a bike with no trail and report back to us on the high speed stability.

You simply don't get it...

If you build a bike with counter-rotating weights and it performs like a normal bike then you've built it wrong. Period.

If you had tried riding one I'm sure you would agree!

I agreed that the trail is crucial for stability - OF THE STEERING GEOMETRY. If you don't have a trail then the wheel can turn too easily and you get into big trouble. However, the reason that you can not sit on your bike with your legs up without falling over if you're not moving is that there are no stabilisation from the gyroscopic forces.

You're saying that the gyroscopic forces have no influence upon the stability of a bike and that it's all to do with trail. Which is bullshit - just like saying that countersteering is the ONLY way to turn a bike...


Notice how there are no vectors for gyroscopic forces in your diagram?

Funny that.

Yes, it is extremely funny - it absolutely took me by surprise since I drew it less than an hour ago.
However, that's because the vector diagram illustrates how the forces work in "a steady state"(constant speed, constant lean angle, no body movement and on a flat surface) during cornering. At that point the rotational momentum of the wheels is irrelevant.

[007XX]

Curiously enough, the only thing that went through the mind of the bowl of petunias as it fell was, "Oh no, not again". Many people have speculated that if we knew exactly why the bowl of petunias had thought that we would know a lot more about the nature of the universe than we do now.

As a token of our appreciation, we hope you will enjoy the two thermonuclear missiles we've just sent to converge with your craft. To ensure ongoing quality of service, your death may be monitored for training purposes. Thank you.

[Ocean1]

Curiously enough, the only thing that went through the mind of the bowl of petunias as it fell was, "Oh no, not again". Many people have speculated that if we knew exactly why the bowl of petunias had thought that we would know a lot more about the nature of the universe than we do now.


As a token of our appreciation, we hope you will enjoy the two thermonuclear missiles we've just sent to converge with your craft. To ensure ongoing quality of service, your death may be monitored for training purposes. Thank you.

Out of the mouths of babes... (pauses to roll up tongue).
What we obviously have here is the effect of a local diurnal or sidereal anomaly, coexistent with anything bearing the name “BIKE”

This explains the beast in question’s total and wilful lack of compliance to the laws of real-world physics. It MAY also explain why an unusually large proportion of otherwise unrelated humans have two completely unrelated features in common. Bikers have all read and memorised THGTTG.

With luck further research will uncover the location of the substantial mass necessary to explain the BIG BANG theory, to wit: several large slices of cake. Stay tuned.

God moves in mysterious ways, his wonders to perform…

[Badjelly]

Out of the mouths of babes

Not me, mate. But 007XX, definitely.

[avgas]

bah, follow the front, drift the back.

[007XX]

What we obviously have here is the effect of a local diurnal or sidereal anomaly, coexistent with anything bearing the name “BIKE”

Especially if you got a Buell apparently...:innocent: and THGTTG rocks!!!


Not me, mate. But 007XX, definitely.


Why you smooth talking bugger...shucks! :o


All kidding aside, I have often wondered if anyone was ever taught how to countersteer by having someone sit behind them as closely to them as possible, and act as a second rider?

Obviously in a secure area like a deserted carpark and not at great speed, but still it offers the possibility of giving a "feel" of the concept that words often make too complicated for someone new to riding.

[MSTRS]

Cogito ergo inclino?




Ok, I'll go and have a cup of tea and a lie down now...

Get a room...
Anyway, where is it written that we can't argue yet still agree on the topique de jour??

[FROSTY]

All kidding aside, I have often wondered if anyone was ever taught how to countersteer by having someone sit behind them as closely to them as possible, and act as a second rider?

Obviously in a secure area like a deserted carpark and not at great speed, but still it offers the possibility of giving a "feel" of the concept that words often make too complicated for someone new to riding.
You need to be at a certain speed before counter steering is really noticable.

[Ocean1]

All kidding aside, I have often wondered if anyone was ever taught how to countersteer by having someone sit behind them as closely to them as possible, and act as a second rider?

Now that you mention it, no.

But what the hell, in the name of science I'll let you sit close and teach me m'dear.

[Maha]

What we obviously have here is the effect of a local diurnal or sidereal anomaly, coexistent with anything bearing the name “BIKE”



WHAT?????.....:confused:

I calculated the compound interest of a parabolic Triangle and got the same answer......''BIKE''...!

[FROSTY]

One thing I've learned and I thing is VERY important to realise is that when riding bikes there are NO apsolutes.
Some use heaps of body endlish some stay planted on the seat. Both get round the same corner.

[MSTRS]

All kidding aside, I have often wondered if anyone was ever taught how to countersteer by having someone sit behind them as closely to them as possible, and act as a second rider?


Actually, that is a great idea. You're not really a woman, are you?
I have done just that, but just sitting on the bike, not moving. Simulating the correlation between push/lean...push harder/ lean more...feet on ground to stop the inevitable...works really well.

[007XX]

Get a room...
Anyway, where is it written that we can't argue yet still agree on the topique de jour??

You just wanna watch don't ya? Ya old perv...:bleh: :dodge:
*luv ya, just kiddin'...please don't beat me up! :hug:*

I was merely asking for maybe some thought to be spared for the morons like me who don't have the mental capacity to grasp such vertiginous concepts such as rotational cavitation or the wonders of Fluctuating capacitators, and was hoping for a more newbie friendly jargon, that all, sir...

Argument is healthy...makes for a great aftermath!:devil2:

[MSTRS]

One thing I've learned and I thing is VERY important to realise is that when riding bikes there are NO apsolutes.
Some use heaps of body endlish some stay planted on the seat. Both get round the same corner.

....usually.

[Maha]

All kidding aside, I have often wondered if anyone was ever taught how to countersteer by having someone sit behind them as closely to them as possible, and act as a second rider?


Na, it aint like a golf swing...gotta teach ya'self something Miss 'V'....:whistle:

[Kickaha]

just like saying that countersteering is the ONLY way to turn a bike...


I'm quite willing to pay for a afternoon at Ruapuna and have you demonstrate a few laps of the track without countersteering, all we'll have to do is find a way to lock your handlebars in the straight ahead position because I really doubt you'll be able to manage it


You need to be at a certain speed before counter steering is really noticable.

Its noticeable at any speed if you're looking for it

[007XX]

You need to be at a certain speed before counter steering is really noticable.

Ok, what speed would you say? in the interest of the debate, of course...


Now that you mention it, no.

But what the hell, in the name of science I'll let you sit close and teach me m'dear.

:blip: you're a pal, I knew I'd be able to count on your selfless nature...:laugh:


Actually, that is a great idea. You're not really a woman, are you?

:rofl: Mebbe, mebbe not...:shifty: I do happen to have seriosu thoughts from time to time, you know...:p


I have done just that, but just sitting on the bike, not moving. Simulating the correlation between push/lean...push harder/ lean more...feet on ground to stop the inevitable...works really well.


Exactly my point...teaching someone new to the game is not always about speed. You got to learn to crawl before you can walk.

[MSTRS]

Argument is healthy...makes for a great aftermath!

No, you're thinking (there's that word again) of abuse...
Just for you...
Counter steering can be looked upon as a term meaning steering counter to direction of required turn...in other words to go left you turn the bars slightly to the right, and counter to expectation that makes the bike lean to the left and it will turn to the left. Vikivirki for turning right. Of course, one must be travelling at or above approx 20kph for this to work...at low speed a turn of the bars will see you going in that direction.
It sounds confusing, no?

[Hitcher]

I have observed that countersteering threads inevitably end in tears and that informed, scientifically-sound discussions about a basic physical principle are impossible.

Therefore, in the interests of public safety and sanity, I am proposing a Kiwi Biker site rule that bans both the phenomenum that is "countersteering" and any related discussion thereof.

The Earth is flat and the sun revolves around it. Get over it.

[Maha]

It sounds confusing, no?

Bum Steering/Counter Steering?

Start on feet stearing John, that'll really confuse the issue....

[Ocean1]

Of course, one must be travelling at or above approx 20kph for this to work...at low speed a turn of the bars will see you going in that direction.
It sounds confusing, no?

I wonder haw much of the trouble sometimes reported by beginers with slow speed turns is within that transitional stage, between "steer where you want to go" and "countersteer speeds".

Don't really notice the transition myself, must have a play to find out where it is on the Buell and see it it feels dodgy...

[Mikkel]

I'm quite willing to pay for a afternoon at Ruapuna and have you demonstrate a few laps of the track without countersteering, all we'll have to do is find a way to lock your handlebars in the straight ahead position because I really doubt you'll be able to manage it

Bloody hell, when will people actually start reading what they're quoting?

Point was just that: saying that countersteering is the ONLY way to turn a bike is obviously not correct since people here have already shared how they can make the bike turn by weight transfer.
Of course you want to be using countersteering to move your bike around precisely and effectively - but it is a combined effort! You'll never be able to follow Casey Stoner if you don't both countersteer and move your weight around.

Also, there's a big big difference between not counter steering and locking your handlebars down. The steering geometry of the bike will cause the handlebar to turn if you lean over the bike. If you prevent this action then I agree that you'd be pretty hard pressed to make your bike turn much faster than an oiltanker.


But hey, it's no surprise that all of these things are pretty damn hard to understand... After all - it is classical mechanics. Or rocket science if you will ;)

[onearmedbandit]

The Earth is flat and the sun revolves around it. Get over it.

I knew it!!!!!

[kiwifruit]

whats countersteering?

[Badjelly]

whats countersteering?
Oh no, not again!

[Hitcher]

whats countersteering?

It no longer exists. See post #110 above.

[Maha]

whats countersteering?

There are alot of Counter Steerer's at New World?....

[Ocean1]

The Earth is flat and the sun revolves around it. Get over it.

Fark, we'll have to come up with another theory now...

[onearmedbandit]

Also, there's a big big difference between not counter steering and locking your handlebars down. The steering geometry of the bike will cause the handlebar to turn if you lean over the bike. If you prevent this action then I agree that you'd be pretty hard pressed to make your bike turn much faster than an oiltanker.




Call me an ignoramus if you like, but surely when you move your body weight and cause the bike to tip in without your hand/s on the bars (which I do regularly) the bike itself is countersteering. Just because you are not directly putting the action in through the bars yourself does not mean the action is not happening. I dare, nay double-dare, anyone to successfully turn a bike at speed by using bodyweight only on a bike with locked bars. Oh that's right, Keith Code already did that for us. But still the debate rages on.

[MSTRS]

Bum Steering/Counter Steering?

Start on feet stearing John, that'll really confuse the issue....

Stirrer. Love your work.

[kiwifruit]

Oh no, not again!

I think i'll start a new thread :yes:

[James Deuce]

OK KB just descended into the realms of fairyland and abuse. Gee how original.

[onearmedbandit]

whats countersteering?

Don't worry mate, you don't do it.

[MSTRS]

Bloody hell, when will people actually start reading ....Point was just that: saying that countersteering is the ONLY way to turn a bike is obviously not correct since people here have already shared how they can make the bike turn by weight transfer.


They are still countersteering...people need to learn to read:whistle:

[kiwifruit]

Don't worry mate, you don't do it.

thats a relief, sounds bloody dangerous

[pritch]

Having read most of the posts in this thread I haven't seen anyone mention weighting the pegs, which method can apparently be used to steer a bike at racing speeds. (I have no intimate knowledge of this but am quoting Shaun from his DVD IoM lap.)

Or should we start a new thread about that?

There are several ways of changing the direction in which a bike is travelling and no one is right 100% of the time. There is a time and place for any and all, so what's to argue about?

[Kickaha]

Point was just that: saying that countersteering is the ONLY way to turn a bike is obviously not correct since people here have already shared how they can make the bike turn by weight transfer.


I have played around with weight transfer to make a bike turn when this argument came up long enough ago that you would have still been shitting in your nappies,and the direction changes that could be initiated wouldn't get you around any 1/2 way decent corner

[Kickaha]

Having read most of the posts in this thread I haven't seen anyone mention weighting the pegs, which method can apparently be used to steer a bike at racing speeds.


I'd never thought to much about this until I did a race with a fractured ankle and was considerably slower as I wasn't able to weight the pegs up to help the direction change

[007XX]

Counter steering can be looked upon as a term meaning steering counter to direction of required turn...in other words to go left you turn the bars slightly to the right, and counter to expectation that makes the bike lean to the left and it will turn to the left. Vikivirki for turning right. Of course, one must be travelling at or above approx 20kph for this to work...at low speed a turn of the bars will see you going in that direction.
It sounds confusing, no?

No, not confusing as this explanation was very well worded. However, a lot of earlier explanations were veering on the borderline nuclear physicist theory paper....sorry buys, just my point of view!


I wonder haw much of the trouble sometimes reported by beginers with slow speed turns is within that transitional stage, between "steer where you want to go" and "countersteer speeds".

Don't really notice the transition myself, must have a play to find out where it is on the Buell and see it it feels dodgy...


I got to admit I really still struggle with a slow tight U turn...can't seem to get the hang of it. However, countersteering on a track day at speed is no longer an issue.

Where could I be going wrong?

[Maha]

Bum Steering/Counter Steering?

Start on feet stearing John, that'll really confuse the issue....


Having read most of the posts in this thread I haven't seen anyone mention weighting the pegs



Thought it would come up sooner or later....

[MSTRS]

It is very simple...riding a bike efficiently is a whole body experience.
Shift of shoulder angle, bum and/or body to one side, weighting pegs, pushing with a knee on the tank, nudging of bars....
The more of these that you combine, the better the result will be.
It is all countersteering to some extent. Obviously the most noticeable technique is the push/pull on the bars, so that is what most do or are taught to do. The other components singly or together do not create enough turn force to be effective in the tight stuff, but will be a thing of beauty in long flowing corners that do not require sharp transitions. For that, you need the bars...


Having read most of the posts in this thread I haven't seen anyone mention weighting the pegs, which method can apparently be used to steer a bike at racing speeds. (I have no intimate knowledge of this but am quoting Shaun from his DVD IoM lap.)

Or should we start a new thread about that?

There are several ways of changing the direction in which a bike is travelling and no one is right 100% of the time. There is a time and place for any and all, so what's to argue about?

A-a ahem.....

[Bass]

You simply don't get it...

If you build a bike with counter-rotating weights and it performs like a normal bike then you've built it wrong. Period.

If you had tried riding one I'm sure you would agree!

I agreed that the trail is crucial for stability - OF THE STEERING GEOMETRY. If you don't have a trail then the wheel can turn too easily and you get into big trouble. However, the reason that you can not sit on your bike with your legs up without falling over if you're not moving is that there are no stabilisation from the gyroscopic forces.



It's taken me a while to get back to this but since I opened the batting on this topic, I guess I should respond.
Sorry mate but while I see your point, I don't agree.
Firstly, it is possible to ride a bike at speeds which are so low that the gyroscopic forces are so small as to be ineffectual and we have all done it.
Secondly, countersteering can be explained by considering the gyroscopic forces on the front wheel only - that's in fact how I have usually seen it explained. So to evaluate precession's part in countersteering, disposing of the angular momentum of the front wheel only, is all that is necessary. There is still the stability provided by the rotation of the rear wheel and the motor. I know that in many cases, the crankshaft rotates in the opposite direction to the wheels, but it still resists movement in some planes.
(To test this for yourself, try changing down a couple of gears next time a crosswind is buffeting you around.)
A quick analysis of the MAGNITUDE of the forces in play leads to the conclusion that there MAY be something other than precession at work. It takes remarkably little effort to tip in a bike of considerable mass that is also spin stabilised by the rear wheel and the motor.

[Mikkel]

Call me an ignoramus if you like, but surely when you move your body weight and cause the bike to tip in without your hand/s on the bars (which I do regularly) the bike itself is countersteering. Just because you are not directly putting the action in through the bars yourself does not mean the action is not happening. I dare, nay double-dare, anyone to successfully turn a bike at speed by using bodyweight only on a bike with locked bars. Oh that's right, Keith Code already did that for us. But still the debate rages on.


I have played around with weight transfer to make a bike turn when this argument came up long enough ago that you would have still been shitting in your nappies,and the direction changes that could be initiated wouldn't get you around any 1/2 way decent corner


They are still countersteering...people need to learn to read:whistle:

Well, I think we need to keep and eye on the difference between steering the bike and actively countersteering in order to make rapid changes of direction.

If there wasn't a distinction between these why would there ever have been a reason to point out the whole countersteering thing in the first place?

While I disagree with some of what Forest wrote the link he provided to the page about trail and such provided a good explanation for what happens when you try to twist the handle bars on a bike the travels at speed. The countersteering action is used to lean the bike over - not to steer it. When the bike leans over the steering geometry takes care of the rest - and no, the steering geometry doesn't cause the bike to countersteer...
Also, as FROSTY wrote - countersteering doesn't really work at low speed, at those speeds you steer the bike around by point the wheel where you want to go.

Anyway, a lot of this commotion probably arises from the fact that the world works in quite a different way than we intuitively understands it. Which is one of the reasons why it took such a long time before a guy like Newton (http://en.wikipedia.org/wiki/Classical_mechanics) (acurate description) sorted out the erroneous assumptions made by Aristotle (intuitive description).

Also, whether I was shitting my nappies or not wouldn't have prevented anyone from reaching the wrong conclusions - indeed the entire history of mankind is quite rife with astounding cases of idiocy.

[Biggles2000]

Sorry Grub I disagree. I believe it is impossible for a bike to go around a corner without countersteering. Body position, and centifugal mumbo jumbo is just tekno babble. A motorcycle goes around corners because it has been placed on a lean by countersteering and the outside of the front tyre has a smaller radius than the centre of the front tyre.

[jrandom]

I believe...

Yes, that's what most countersteering discussions boil down to.

[Mikkel]

It's taken me a while to get back to this but since I opened the batting on this topic, I guess I should respond.
Sorry mate but while I see your point, I don't agree.
Firstly, it is possible to ride a bike at speeds which are so low that the gyroscopic forces are so small as to be ineffectual and we have all done it.
Secondly, countersteering can be explained by considering the gyroscopic forces on the front wheel only - that's in fact how I have usually seen it explained. So to evaluate precession's part in countersteering, disposing of the angular momentum of the front wheel only, is all that is necessary. There is still the stability provided by the rotation of the rear wheel and the motor. I know that in many cases, the crankshaft rotates in the opposite direction to the wheels, but it still resists movement in some planes.
(To test this for yourself, try changing down a couple of gears next time a crosswind is buffeting you around.)
A quick analysis of the MAGNITUDE of the forces in play leads to the conclusion that there MAY be something other than precession at work. It takes remarkably little effort to tip in a bike of considerable mass that is also spin stabilised by the rear wheel and the motor.

You say you disagree - except it doesn't really seem so to me.

The part I've highlighted is the only thing I have any contentions with... You say the gyroscopic forces are ineffectual. Not quite so - the gyroscopic forces are present from the second your wheels start turning and from that second they are providing stability. That stability increases with the rotational speed and vice versa. This is why it becomes more and more difficult to ride a bike as you slow down and there's a lower limit for how slow you can ride in a straight line - if it was all TRAIL then this wouldn't be the case. Q.E.D.

For the rest of your post - yes I mostly agree. But I don't find anything there that is in disagreement with what I have already written. You wonder about how little effort is necessary to tip a big bike over using the handlebars - I'd say that's due to leverage and steering geometry. I wanted to chuck a couple of formulas in here for good measure showing how the vectors from the torque applied at the handle bars translate into a roll inducing change of the rotational momentum of the front wheel. But alas, I've grown rusty in the finer parts of classical mechanics and can not be bothered to study my old mechanics book thoroughly now - too close to beer'o'clock as it is.

Anyway - a video probably says more than a thousand words. I'd like you guys to try and explain what happens in this one:

http://www.youtube.com/watch?v=545GwnupKAE&feature=related

http://www.youtube.com/watch?v=2pYi3-q_IVA&feature=related

Oh yeah, and please do continue to argue against gyroscopic stability induced by rotational mass!

[Deano]

Here's the true bum steer. Pic included.

[Mikkel]

Can't help myself...

This video shows nicely how the interplay of applied torque and rotational mass pans out:

http://www.youtube.com/watch?v=dCcfKBfmyP4&feature=related

[swbarnett]

I've been watching and reading all the countersteering threads of late and someone's comment "... if you're getting around corners, then you must be coutersteering, can't be done otherwise ..." has prompted me to post a counter-view on counter-steering.
I got that from a paper in a Physics journal talking about how bicycles steer.


Watch the top racers, watch the best of them Casey Stoner. Their bodies are on the inside of the bike before they tip in for the corner. ... They are pushing the bars up to hold the bike straight waiting for the tip in.
This is the old "pick up the hammer while you're standing on it" theory. You can't push the bars up unless you've got something to push against. The rider is hanging in mid-air.

If unbalanced weight was all that was required to turn then these riders would start turning the moment they shifted their weight and bikes would be a lot more unstable than they are. The reason that they don't is that the gyroscopic force must be counter-acted before the bike will lean. When the rider tips in to the corner they are counter-steering. They're not holding the bike up, they're holding the bars straight. When they relax their arms the bike leans. Possibly in response to this a counter-steer occurs. So, even when you're using your body weight to aid the "tipping in to the corner" counter-steering is still involved.

[MSTRS]

No, not confusing as this explanation was very well worded. However, a lot of earlier explanations were veering on the borderline nuclear physicist theory paper....sorry buys, just my point of view!




I got to admit I really still struggle with a slow tight U turn...can't seem to get the hang of it. However, countersteering on a track day at speed is no longer an issue.

Where could I be going wrong?

Steering a bike in a variety of situations, and at various speeds simply takes practice. The transition between turning the bars and nudging is a fine line, that will be at different points for different bikes/styles of bike. At low speeds (walking pace) your body position on the bike assumes greater importance than at higher speeds when countersteering kicks in.
You say you have trouble with low speed, tight u-turns but have countersteering sorted...so does Yungatart. Perhaps it's a woman-thing?? I suggest you avail yourself of a course at RRRS - Noel (The Stranger) will get you sorted.

[Paul in NZ]

Fark - I don't think of any of this when I'm out for a ride... Its more...

hmm..corner comin up.. hmm wonder if Vickis in the mood tonight? corners gettin closer - christ I could go a beer about now... corners gone cor that was cool... hmm wonder if Vickis in the mood tonight? next corners gettin closer - christ I could still go a beer about now... corners gone cor that was cool... hmm wonder if Vickis got any beer in the fridge? Shit - did I check the tyres? Oh yeah - I was going to do that after I put the beer in the fridge but I aint dead so I guess they are ok... Christ whats that bloody noise? Vicki won't be in the mood tonight if I blow the bike up again next corners gettin closer - christ I'm still thirsty... corners gone cor that was cool... hmm wonder if I can remember all the words from that song... dah dah dum.. no um dum dah argh fug it ..... If I stop and call I could check if Vickis in the mood tonight? corners gettin closer - christ I could stop for a beer at the same time eh?... corners gone cor that was cool... hmm nah - she will hate it if she smells beer on my breath... Vodka - yeah - that could work... nah - best not eh - coffees the go... Yeah - that would put me in the mood eh?

Countersteering? I had a counter once and it didn't steer too well...

[MSTRS]

Yeah Paul - that'd work. Vicki being 'in the mood' is counter to reality, hence the corners go by nicely?? And beer (or vodka) are bought over the counter, so that's working too. And the song in your head...only works if it incorporates a counterpoint rhythm.

[Biggles2000]

Yes, that's what most countersteering discussions boil down to.

Well if you would like to try following me around a few corners with your hands off the bars with out crashing....... which I believe is impossible to do as the bike would simply go straight ahead...... then you are right and you can bum steer. Try it please?

[Mom]

I have played around with weight transfer to make a bike turn when this argument came up long enough ago that you would have still been shitting in your nappies,and the direction changes that could be initiated wouldn't get you around any 1/2 way decent corner

Agreed! but combined with other strategies it helps! and IMO should be also factored into the equation.



It's taken me a while to get back to this but since I opened the batting on this topic, I guess I should respond.


Please do...LOL cant understand a word mind. follow what you are saying, but way too technical for the mere plebs like me on here to understand.



Fark - I don't think of any of this when I'm out for a ride... Its more...


I think a lot of riding is instinctive, and learned by experiencing and/or being taught, nothing to do with mathematics, physics or what have you. If it were about that I would have given up before I even started.

For me it is a combination of what needs to be done to get around that corner. I came back to riding on my sons pathetic scooter. It had fat tyres and cornered like it did not want to!! I did the lean/countersteer/weight transfer thing (albeit at 50kmph) and I was not going to get round without hitting the council formed drain on the side of the road. Stomped on the peg inside peg, and away we went. It is not a science in IMO, it is what you have to do to make the turn, and the skill level you possess to enable you to do it!


Feet steering has to be a factor too!

[Ixion]

Call me an ignoramus if you like, but surely when you move your body weight and cause the bike to tip in without your hand/s on the bars (which I do regularly) the bike itself is countersteering. Just because you are not directly putting the action in through the bars yourself does not mean the action is not happening. I dare, nay double-dare, anyone to successfully turn a bike at speed by using bodyweight only on a bike with locked bars. Oh that's right, Keith Code already did that for us. But still the debate rages on.

Yes. That is exactly correct. For a bike to corner at any speed , the front wheel must be perversely displaced (ie turned a bit right if you want to go left). That is the counter steer mechanism.

Whether you initiate that displacement by pushing the handlebars (consciously 'countersteering'), or by causing the bike to lean over (by weight shift or banging your knee on the tank or whatever) makes no difference.

In the first case the wheel displacement will cause the bike to lean. In the second case , the lean will cause the wheel to displace. It works the same either way round

Conscious countersteering (with the bars) is manifestly not the only way to cause the counter-steer dispalcement . (It may be the best but that's a different argument).

But regardless of how initiated, a bike cannot corner at speed without involving the counter-steer mechanism.

Both parties are correct. Any (highish speed) cornering on a bike is countersteering - but it need not be the rider pushing the bars which causes it.

[dhunt]

I thought I would add to the confusion by quoting a few of the top riders in MotoGP. Taken from the MotoGP: Performance Riding Techniques Book



It's not something for me that you can draw on a chalkboard. As far as counter-steering and body-steering go, I think a lot of riders guess and don't really know what they do or don't understand. I mean, I just try to get around the track as fast as I can!"




Erm, erm, it's just erm, I dunno! It's just natural.




When I'm turning right I push on the right bar. Sometimes if the corner is really fast then I pull on the left one too but not very often.




I think it depends on the speed - at 100mph I definitely counter-steer. I pull a little bit right to go left




I use my body. Push my shoulder to the inside of the corner




Your bike's handlebars, of course, play the big part in steering, but your footpegs help you to steer the bike too.




I have small levers; my arms are shorter so I haven't as much power as Gibernau, so I use my body and legs as well. I move and use a lot of leg like if you were to break a stone.


And here's a summary from the book itself


Putting pressure on the inside footpeg to try to get the bike to turn is a waste of time and effort. Logic should dictate that putting more of your body mass on the inside peg will get the bike to lean, and experimentation in a car park or in a really slow turns would support this theory.
But once your bike gets up to speed and the strong gyroscopic forces from the front and rear wheels come into play, then the only thing that putting pressure on the inside peg will do is make your thighs a bit bigger.

Just leaning into the corner and hoping that the bike will follow is also a waste of time and effort. I'll admit that doing this can give you a slight change of direction, but will it make the bike turn? Will this alone get the bike into and out of a corner? The answer is no. You'd to have the turning arc of an oil tanker for this to work - and that isn't going to be of much use, or very exciting, for a bike.

But even MotoGP riders aren't too sure - or even in agreement with each other - on some of the essential steering points.


Hopefully this helps.

[Forest]

Oh yeah, and please do continue to argue against gyroscopic stability induced by rotational mass!

I don't think anyone here is arguing against the existence of gyroscopic forces.

At least I hope they aren't!

[smoky]

I’ve never heard so much twaddle about a very over done subject in one thread before.
Actually I have but; I think you’re taking things too far out of context – body position is important, counter-steering is important, so is throttle control, where you’re looking, your line, weighting the peg, bla bla bla - get them alright in the same corner and you have the best result.

Some of your comments about counter steering makes me wonder if you even know what it is – and suggest you use it a hell of a lot more than you think


If it didn't work, racers wouldn't be using it (watch the MotoGP slow motions to see it in action).

trust me - they still use counter-steering, I don’t think you can watch a GP racer and actually even see the counter-steer being applied, even in slow motion. So your just guessing at what they’re doing based on your own experience - unless you’ve got a reference to someone riding in a GP who is saying the same as you.


I've been using the technique for a year and perfected it on my daily runs over Paekakariki Hill Rd - there's not a better test.

Well I guess when we're faced with soo much experience - how can we argue against that.


You can tell the obsessive counter-steerers, they're the ones who look like motorcrossers when you're following them on the road - body upright while they push the bike down in a desperate attempt to carver the corner.
Not sure who you’ve been riding with – have you ever read anything that say’s ‘stay upright when you use counter-steering’. Just because you ride with people who do something odd doesn’t mean shyte.

[Ocean1]

I got to admit I really still struggle with a slow tight U turn...can't seem to get the hang of it. However, countersteering on a track day at speed is no longer an issue.

Where could I be going wrong?

And this from an ex dirtygirl. *sigh*

I figure you already know, lean the bike and keep your body weight over the tyre's contact patch. Helps if you load up the uphill peg too, same as in the dirt. In fact I'm embarrased to say I sometimes do it standing up :o Just seems easier to pretend the Buell's a KT250 :laugh: No, don't do that, but there might be a clue there about weight transfer eh? And throttle control.

Appart from that, it's just an afternoon in a carpark, making with the little wee circles. :niceone:

[pete376403]

All this talk of the wheels gyroscopic effect but I dont think anyones mentioned the other gyro -the crankshaft - yet.

[Grub]

Are you suggesting I should move my body to the inside?...

Well yes ... and no. It's a very individual thing and it's raised as a talking and a trial thing to see if anyone finds it interesting enough to have a play with it.

I personally do lean inside, shoulders, head and bum. The degree of that movement is very much dependant on the speed and agressiveness of the ride. At a casual cruising pace the shoulders and head go in which just weights up the inside bum cheek and for me it really really works. Carving through Paekak Hill Rd I can pull the bike down to me or push it away from me to adjust to a tightening or opening of the corner. And yup, I pretty much do it for most corners pacier than a pootle.

[Grub]

Try it. Walk beside your bike. Now, lean it over (I suggest toward you), but hold the bars straight ahead. Keep walking. Are you going in a circle? Thought not. It would be quite hard to push the bike to the gas station if it were not so..

No mystery here I think. If you "hold the bars straight" of course the bike will go straight.

Lean it instead by holding onto the grab bar at the back and the bike will turn. We know this because we have all walked along pushing our pushbikes by the seat and leaning them to turn.

Remember that this thread isn't about "countersteering is bunkum" even though it has been construed as such.. It's about using body position to give a natural impetus to the turn. It helps, it is controlled and it does work.

[Ixion]

Yes, but my point was that leaning the bike does not of itself provide any cornering capability. As you yourself say, leaning will cause steering movement and THAT causes cornering.

So it is not possible to corner just by leaning. You MUST provide steering input , or at least allow it to happen. And that is, by definition, countersteering, if the speed be great enough. Whether you countersteer by pushing the bars or forcing the bike to lean over and move the bars , as in your bicycle example.

[dipshit]

The countersteering action is used to lean the bike over - not to steer it. When the bike leans over the steering geometry takes care of the rest

This is the way I think of it and can see why some people are getting confused.

Countersteering causes a gyroscopic effect with the spinning front wheel that causes the bike to lean over. This youtube video shows it best perhaps, but imagine the guy facing down towards the ground while doing that. The effect will be to lean the bike over.

<object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/u47eMRgJoBQ&rel=1"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/u47eMRgJoBQ&rel=1" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>

When a bike is travelling in a straight line, the centre of gravity is in line with the contact patch of the tyres. (fig 1) When the bike leans over, the centre of gravity is moved to the inside of the turn and the bike will travel in that direction. (fig 2) To demonstrate that lean angle alone does not make a bike go around a corner, imagine a bike leaned over but with the rider completely hanging off on the outside and moving the centre of gravity back over to the contact patch of the tyres. (fig 3) In such a case the bike will still travel in a straight line even though it is leaned over.

Countersteering is a good way to lean the bike over... then the large change in the centre of gravity causes the bike to go around the corner. A rider that only shifts their body weight is only making a small change on the centre of gravity, so the bike will only slowly go around a corner.

[dipshit]

And watch this one for how controllable the effect is.

<object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/dVwKE9yDqVo&rel=1"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/dVwKE9yDqVo&rel=1" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>

[swbarnett]

All this talk of the wheels gyroscopic effect but I dont think anyones mentioned the other gyro -the crankshaft - yet.
I think the crankshaft is too small a diameter to possess much angular momentum involved. The wheels, having a large diameter, have a far greater effect.

[FROSTY]

Instead of sitting behingd a friggin puter screen why not get on ya bike go for a ride and find out?
find a quiet bit of road and experiment ?

[Sully60]

I think the crankshaft is too small a diameter to possess much angular momentum involved.

Adrian Gorst and Colin Edwards II they may have a differing opinion on that matter.

[MSTRS]

.... To demonstrate that lean angle alone does not make a bike go around a corner, imagine a bike leaned over but with the rider completely hanging off on the outside and moving the centre of gravity back over to the contact patch of the tyres. (fig 3) In such a case the bike will still travel in a straight line even though it is leaned over.


Rubbish. Unless the bars are fixed in the straight-ahead position. We've been over this already. How does 'dirtbike/motard-style' work then?

I think the crankshaft is too small a diameter to possess much angular momentum involved. The wheels, having a large diameter, have a far greater effect.
Then can you please explain why a bike is more stable in a corner at higher revs...

[swbarnett]

I think the crankshaft is too small a diameter to possess much angular momentum.
Adrian Gorst and Colin Edwards II they may have a differing opinion on that matter.
I'd be happy to stand corrected on this. I based my comment on nothing more than apparent logic.

[swbarnett]

Then can you please explain why a bike is more stable in a corner at higher revs...
It seems I spoke too soon. Just seemed logical at the time. What you say makes a lot of sense.

[Ocean1]

Rubbish. Unless the bars are fixed in the straight-ahead position. We've been over this already. How does 'dirtbike/motard-style' work then?

Think that's what he was getting at, the bars need to move AND the bike to lean.

Actually, just to chuck in a wee red fishy thing, lean angle is only relevant at countersteer speeds, you can turn a trials bike the opposite way to the lean, simply by compensating with body weight to maintain the CG over the contct patch.

Edit: I think that's be possible at higher speeds too, if you could get enough mass inside, but I ain't trying it.

[Bass]

I am lagging behind the discussion yet again. However, being a pedantic SOB, I think the following is worth a reply

You say you disagree - except it doesn't really seem so to me.

Oh yeah, and please do continue to argue against gyroscopic stability induced by rotational mass!


I don't think anyone here is arguing against the existence of gyroscopic forces.

At least I hope they aren't!

Forest has it right.
I have never argued that precession was not a factor in countersteering. What I have contended is that it is NOT THE MAJOR FACTOR.

As evidence, I made mention of a bike that had been created with contra-rotating counterweights (which would negate gyroscopic forces) but which reportedly countersteered just fine.

You contend that such a bike is unlikely because it is Gyroscopic stabilisation which makes it easy to ride a bicycle and so getting rid of it would make the bike difficult/impossible to ride.

My comment on this was that one only needs to annul the angular momentum of the front wheel to investigate the part that precession plays in countersteering. This leaves in play, the gyroscopic forces generated by the rear wheel and the motor and so such a bike would not be particularly difficult to ride at all.

Your move I think.

[dhunt]

A forced experiment on this subject that I had at Manfeild a few months back when my front tyre started going flat on me certainly emphisised (sp?) the necessity of counter steering to me.

What happened is the bike had a huge tendency to standup and to actually get the bike to navigate the corner required large amounts of force in the opposite direction (Counter steering) to where I wanted to go. No amount of leaning off made any difference due to the tendency of the bike to standup. As the tyre got flatter the more force was required to get it to turn.

Now while I don't suggest any one go out and try this experiment it certainly proves the point.

[Mikkel]

I am lagging behind the discussion yet again. However, being a pedantic SOB, I think the following is worth a reply

No worries ;)



Forest has it right.
I have never argued that precession was not a factor in countersteering. What I have contended is that it is NOT THE MAJOR FACTOR.

Well, to me it sounded like you guys were arguing that the gyroscopic forces were not a factor...


As evidence, I made mention of a bike that had been created with contra-rotating counterweights (which would negate gyroscopic forces) but which reportedly countersteered just fine.

And I just said that making something like that is bloody difficult since the counter rotating weights would have to have exactly the same rotational inertia AND rotate around the same axis as the tyre in order to counter the rotational momentum of said tyre. I'm not saying it's impossible to make such a machine - but it's pretty fucking difficult though! So chances are that you could get it wrong... And my argument was that if you didn't notice any significant change in the behaviour of the bike (especially if you cancel both front and rear tyres) - then I'm 100% sure you haven't succeeded in countering the rotational momentum properly.



You contend that such a bike is unlikely because it is Gyroscopic stabilisation which makes it easy to ride a bicycle and so getting rid of it would make the bike difficult/impossible to ride.

My comment on this was that one only needs to annul the angular momentum of the front wheel to investigate the part that precession plays in countersteering. This leaves in play, the gyroscopic forces generated by the rear wheel and the motor and so such a bike would not be particularly difficult to ride at all.

Indeed - with no balancing from any rotational momentum it would be very difficult (i.e. countering both front and rear).
And yes - the balancing from the rear wheel would be adequate to stay upright. However, riding at very slow speeds ought to be more difficult than usually.
I agree that the trail would stabilise the front wheel and prevent it from changing direction.
However, I'm confident that steering input would be very much different than usual. I'm not going to say that you couldn't use countersteering to lean the bike over - changing the geometry of the bike will have an effect on what the bike does... So much is obvious.

If you watch the videos I posted earlier you can see how even small gyroscopic forces seemingly can suspend gravity... If that does not clearly illustrate how powerful these forces are then I don't know what will. Also, the video with the double gyro illustrates exactly what happens when you counter steer - you apply a small torsional force upon the rotating mass and it tilts along the third axis.

As for the engine helping with balancing the bike - I doubt very much that the effect of the crankshaft would be measurable compared to the flywheel (I assume bikes have flywheels here...).

[Bass]

It seems I spoke too soon. Just seemed logical at the time. What you say makes a lot of sense.
If you want to test the effect the engine has on your stability, next time you are being knocked around by a cross wind, change down a gear of two but maintain your speed. You may be surprised.


No worries ;)
And I just said that making something like that is bloody difficult since the counter rotating weights would have to have exactly the same rotational inertia AND rotate around the same axis as the tyre in order to counter the rotational momentum of said tyre. I'm not saying it's impossible to make such a machine - but it's pretty fucking difficult though! So chances are that you could get it wrong... And my argument was that if you didn't notice any significant change in the behaviour of the bike (especially if you cancel both front and rear tyres) - then I'm 100% sure you haven't succeeded in countering the rotational momentum properly.

Firstly, I agree that it is difficult, although I can think of several ways in which it could be achieved - the radial aero engine in the front of our aeroplane does all the things you describe as far as concentric motion goes. Further, it seems to me that if someone was prepared to put in the work to do it, they would put in the time to do it right.
Don't you think that your claim that because it did not perform the way you expected then they got it wrong, sounds just a bit arrogant?
Having said that, it took me by surprise too and I was just as difficult to get to derail my train of thought.
Whether the guy got it right or not quite right, it still seems to me that if the rider was able to countersteer the machine AT ALL, then my point is proved. Instead, the report was that it READILY countersteered and so surely my point is doubly proved
Any handling difficulties encountered seem to me to be completely irrelevant to the question of what the predominant reason for the countersteering phenomenon is.
It could be a total bastard to ride but if it readily countersteered with little or no nett angular momentum at the front wheel, then the major reason for countersteering happening cannot be gyroscopic precession.
I would still like to be convinced otherwise however, because I like neat and tidy theory.






If you watch the videos I posted earlier you can see how even small gyroscopic forces seemingly can suspend gravity... If that does not clearly illustrate how powerful these forces are then I don't know what will. Also, the video with the double gyro illustrates exactly what happens when you counter steer - you apply a small torsional force upon the rotating mass and it tilts along the third axis.

I disagree.
Surely, within the scope of this discussion, these machines obey Newtonian mechanics with the proviso that because of the rotation, the output is perpendicular to the input.
Consider the bike wheel suspended by string at the end of the axle. It rotates slowly around the string.
Why only slowly?
Only small frictional forces retard it.
If the force were large it would rotate rapidly around the string.

In this case, because the axle is short, the string takes most of the weight and the precessive force is small.

You get out what you put in - the gyroscopic forces are as strong as you make them.

I enjoyed your videos largely because I remember carrying out ALL those experiments in the physics lab at high school. The double disc gyro that we used was actually the master gyro out of a Lancaster bomber.



As for the engine helping with balancing the bike - I doubt very much that the effect of the crankshaft would be measurable compared to the flywheel (I assume bikes have flywheels here...).
Yes most bikes have a flywheel but it is usually quite low mass
The cranks are usually a disc and pin arrangement to reduce the width of the engine. The do not have a huge mass but they are solid enough and at the speeds the modern engines spin, the crank has a quite noticeable effect.

[Ixion]

Instead of sitting behingd a friggin puter screen why not get on ya bike go for a ride and find out?
find a quiet bit of road and experiment ?

Because, when I was much younger, and know-it-all even younger types started spouting on about this new counter steering that had just been invented, I did indeed get on my bike and perform quite a few experiments on a quiet bit of road (off road actually) . Such conclusions as I reached were at the expense of no little pain and bruising. I prefer to stick to theory nowdays.

[Ixion]

Think that's what he was getting at, the bars need to move AND the bike to lean.

Actually, just to chuck in a wee red fishy thing, lean angle is only relevant at countersteer speeds, you can turn a trials bike the opposite way to the lean, simply by compensating with body weight to maintain the CG over the contct patch.

Edit: I think that's be possible at higher speeds too, if you could get enough mass inside, but I ain't trying it.

No I think (but my head as asploded from all this so I haven't really thought it through), that you only need the bars to move (and thus the wheel. When that happens, gyroscopic effect will cause the lean. But the lean on its own , with the bars kept straight ahead does nothing - my example of pushing your bike to the gas station , leaning it inward toward you to make the pushing easier.

I think that is why the counter rotating thing doesn't work , too. The lean on a bike doesn't CAUSE the bike to corner. It's a RESULT of the bike cornering , OR the thing that initiates the cornering (by causing the wheel to counter steer). So , I think, in theory, fixing counter rotating weights to both wheels (needs to be both) , you could still counter steer the bike, and doing so would make it corner , but it would stay upright (you could still cause it to lean, though, by hanging off etc). In fact , didn't Honda make a little bike that had a built in gyro that did exactly that ? Called, in fact, the Honda Gyro ?

[GSVR]

Ever missed a downchange and hit a false neutral on the track going into a high speed corner where you engine would pull high revs on the downchange.

I don't know if its the sudden loss of revs and consequent loss of motor gyro effect or just the dissengagement of the rear wheel to the motor but things feel very different and you usually end up running wide or in some cases off the track if you had a deep line.

[Sully60]

In fact , didn't Honda make a little bike that had a built in gyro that did exactly that ? Called, in fact, the Honda Gyro ?

What?!

Do you mean those three wheeled things with roof's the Hell Pizza guys ride have got gyros? Is that to keep pizza level to stop the toppings form coming off?:confused:

[Deano]

I don't know if its the sudden loss of revs and consequent loss of motor gyro effect or just the dissengagement of the rear wheel to the motor but things feel very different and you usually end up running wide or in some cases off the track if you had a deep line.

It's all in ya head.

There's no such thing as countersteering or weight shift - just don't think about it and you'll be sweet.

[Ixion]

Actually, after thinking a little more ( one beer's worth more, actually), I think the major effect of gyro force on a motorcycle , is not to enable it to corner, but to prevent it cornering. Or, more exactly, to stabilise it so it doesn't fall over.

Stationary, or at low speeds, a bike falls over. We all know that, those of us with short legs more than most. Go fast, it doesn't fall over. Or, not as easily. Except for Gixxers of course.

The reason being that gyro stuff. If the bike tries to fall over to one side or other, gyro force then wants to move the handlebars and make the bike go in a curve. But this force is resisted, and controllably so, firstly by the stability effect of the trail (as someone mentioned) and if the is not enough (eg, strong winds gusts) by you, the rider, pushing on the bars to prevent it.

Incidentally the 'pushed over by strong winds, feel it through the bars' effect is an evidence of the point I made earlier, that lean causes steering, not just the other way round.

[Sully60]

What about Segways?

Apart from them being extremely ghey!

[pete376403]

10 - 20 kilos of crank spinning at 8 -10,000 or better is going to have a LOT of gyroscopic effect.
One of the reasons GP bikes (Yamaha OW70, Cagiva, went to twin cranks was that, as they were contra-rotating, they cancelled each others gyro effect.
Quote:".. Ever since '84 there had been dark mutterings about 'single-crank voodoo' and a growing belief that the crank's gyro effect was responsible for the bike's wayward handling. In other words, crankshaft inertia made it hard work to steer the bike from its current course. Yamaha ran contra-rotating cranks, which canceled out any gyro effect, HRC thought that was the reason the Yamaha handled better." http://www.superbikeplanet.com/NSR500.htm

[RearWheel]

From my limited experience (39yrs riding) with only 1 binning to my name (should i feel ashamed?) I have found from personal experience that its simply a combination of body language and counter steer that gets you round the corners. For myself going into a corner i very subtley use a combo of both at the same time and once fully in i use body weight and position to keep it where i want it..... except where a sudden line change is called for say in mid corner and then counter steer is really your only option for a quick reaction.... think about it , its quicker to tweek the bars mid corner than it is to move ur body to change your line in a hurry when you want to avoid that rock or possum laying right in your line. All the theries about gyro forces dont mean squat when ur 1 second from disaster, you just do what ya gota do to avoid bining your baby and busting up ur arse. In a word just do what comes naturally which may be different things for different riding levels , but you sure cant get to the higher levels without having a few momments and those "close calls" are what gives you the experience to go on and be a more aware more skilled rider...... live in peace ride in safety and learn from your mistakes.
Oh and one more thing .... dont let anyone ever goad you into riding past ur experience level...... I have much respect for one young fella ( Hornetboy) whom i had the pleasure of riding with last wednesday and i was razzing him a wee bit about riding like a nana (just kiddin with ya of course) but he was riding at a level he was comfortable with..... and thats the key to it ... keep ya head up and wheels down..... cheers

[007XX]

And this from an ex dirtygirl. *sigh*

I figure you already know, lean the bike and keep your body weight over the tyre's contact patch. Helps if you load up the uphill peg too, same as in the dirt. In fact I'm embarrased to say I sometimes do it standing up :o Just seems easier to pretend the Buell's a KT250 :laugh: No, don't do that, but there might be a clue there about weight transfer eh? And throttle control.

Appart from that, it's just an afternoon in a carpark, making with the little wee circles. :niceone:

:o yeah, yeah I know...:sweatdrop

It all seemed so much simpler in the dirt...*sigh* Oh well, definitely will get my arse in a carpark practicing then.

Mind you, the only time I did try a tight U turn, I was exhausted after 4 days pretty much solid of riding, so it could have had something to do with it.:zzzz:

[Mikkel]

Don't you think that your claim that because it did not perform the way you expected then they got it wrong, sounds just a bit arrogant?

Arrogant - perhaps. But I do happen to have a good friend who's both a genius and very much into doing what he calls a "Science Show" wherein a lot of the more freaky and showworthy physical phenomenon are put on display. Anyway, this fella once rode a bicycle where they had fixed a set of counter rotating wheels that matched the wheels on the bike 100%.
He said it was quite impossible to ride - and you would be all over the place with no stability at all.


Whether the guy got it right or not quite right, it still seems to me that if the rider was able to countersteer the machine AT ALL, then my point is proved. Instead, the report was that it READILY countersteered and so surely my point is doubly proved
Any handling difficulties encountered seem to me to be completely irrelevant to the question of what the predominant reason for the countersteering phenomenon is.
It could be a total bastard to ride but if it readily countersteered with little or no nett angular momentum at the front wheel, then the major reason for countersteering happening cannot be gyroscopic precession.
I would still like to be convinced otherwise however, because I like neat and tidy theory.

Not really. Unless he got it exactly spot on there would still be gyroscopic forces at play, albeit weaker. And then you could just as well argue that it just illustrates how important these are.

Please note that I haven't at any point said that countersteering is ONLY due to gyroscopic forces. However, I'd have to see something more substantial than a vague claim, with no references, that someone has proven gyroscopic forces not to be a major factor in the mechanics of motorcycles before I'm willing to accept it.
Because, as you say, the theory is neat and tidy - not easily understood in a compound 3D environment - but still it is pretty much bullet proof.


I disagree.
Surely, within the scope of this discussion, these machines obey Newtonian mechanics with the proviso that because of the rotation, the output is perpendicular to the input.
Consider the bike wheel suspended by string at the end of the axle. It rotates slowly around the string.
Why only slowly?
Only small frictional forces retard it.
If the force were large it would rotate rapidly around the string.

In this case, because the axle is short, the string takes most of the weight and the precessive force is small.

You get out what you put in - the gyroscopic forces are as strong as you make them.

Still, as you say the axles are short which means that gravity working on the COM will only provide a small amount of torque compared to the rotational inertia of a bike wheel with a fairly large radius.

I'll even expand and go in utter nerd mode and throw equations at you just to prove my point. Neglecting the mass of the axis itself and assuming the weight of the bicycle wheel, m, can be described as a toroidal mass we have an rotational inertia, I, equal to m*R^2 where R is the radius of the wheel. Given that l is the length of the axle and the gravitational acceleration is g we have the following expression for the torque, t, around the point at which the string is affixed:

t = l/2 x m*g

The change in rotational momentum, L, is given by:

dL/dt = t = l/2 x m*g

If we let F describe the angular frequency around the vertical axis and f decribes the, constant, angular frequency of the wheels rotation around the axle we get the following:

dL/dt = F*f*I = l/2 x m*g
<=>
F = l*m*g/(2*f*I) = l*g/(2*f*R^2)

The last formula illustrates the motion - note that the weight of the wheel cancels out due to our assumptions and the fact that it's gravity providing the torque.
The rate of precession grows linearly with the applied torque - e.g. axle length and gravitational pull - however there's an inverse relation with the angular frequency and an inverse square relation with the radii of the wheel.

So, yes you get what you put in (linear relationship) - but the bigger the gyroscopic forces the harder you have to work to achieve the same result. And so, in the case of the video where R is much larger than l it's no wonder that the rate of precession is small.

Sorry for being long winded - and even more sorry I couldn't be arsed making a sketch...

[GSVR]

Arrogant - perhaps. But I do happen to have a good friend who's both a genius and very much into doing what he calls a "Science Show" wherein a lot of the more freaky and showworthy physical phenomenon are put on display. Anyway, this fella once rode a bicycle where they had fixed a set of counter rotating wheels that matched the wheels on the bike 100%.
He said it was quite impossible to ride - and you would be all over the place with no stability at all.


This is interesting and had me think of a different way to reverse the steering inputs. What if the steering wheel was the one on the back of the bike?
Then to get a gyroscopic induced lean you would have to turn into the corner if you get the idea. Still away but the away movement would be turning the corner.

[Badjelly]

What if the steering wheel was the one on the back of the bike? Then to get a gyroscopic induced lean you would have to turn into the corner.

Many years ago I made a skateboard with a castor wheel, the sort they use on furniture. (I'd already worn out the one I made earlier with my sister's roller skates.) I put it at the top of the hill with the castor wheel at the back and stood on it--it swapped ends on me. There was no way that thing would go down the hill with the castor on the back, but it was perfectly happy with the castor at the front.

So, I think the answer is that a bike with the steered wheel at the back would insist on swapping ends to bring the steered wheel to the front.

[GSVR]

Many years ago I made a skateboard with a castor wheel, the sort they use on furniture. (I'd already worn out the one I made earlier with my sister's roller skates.) I put it at the top of the hill with the castor wheel at the back and stood on it--it swapped ends on me. There was no way that thing would go down the hill with the castor on the back, but it was perfectly happy with the castor at the front.

So, I think the answer is that a bike with the steered wheel at the back would insist on swapping ends to bring the steered wheel to the front.

Yes but your castor wheel didn't have handlbars did it and the rake and trail were all wrong (it didn't have any)

[Badjelly]

Yes but you castor wheel didn't have handlbars did it and the rake and trail were all wrong (it didn't have any)

No handlebars, no. It had a vertical steering axis (rake = 90 deg???) and about 3 cm trail. Not exactly analogous to a bike, but I suggest nevertheless that a bike with the steered wheel at the back would not track stably.

[Ocean1]

Yes but your castor wheel didn't have handlbars did it and the rake and trail were all wrong (it didn't have any)

But if it did, would it respond to countersteering input the same as a cicle?

[Ocean1]

No handlebars, no. It had a vertical steering axis (rake = 90 deg???) and about 3 cm trail. Not exactly analogous to a bike, but I suggest nevertheless that a bike with the steered wheel at the back would not track stably.

I can attest to that, I've navigated many downhills going arsy versy, usually directly after an attempted hillclimb.

Not stable at all, at all.

[Badjelly]

would it respond to countersteering input the same as a cycle?

In case anyone's interested, I steered the castor-equipped skateboard by putting weight over the front wheel and leaning. It handled quite well, actually. Mind you, it was arguably a tricycle, because at the back it had a double-wheel unit from another sister's pair of skates.

With motorbikes and pushbikes at over 30 km/h, I have found that leaning has pretty close to zero effect unless accompanied by handlebar inputs. But I think that subject has been thrashed pretty hard already on this thread.

[Badjelly]

By the way, wouldn't it be neat to look at the output from a steering position sensor on a bike? I don't really know what it would show, or what it would mean, but it would be neat. I suspect with most riders (even the determined anti-counter-steerers) there'd be a little outwards blip at the start of the corners and a little inwards blip at the end.

[Sully60]

By the way, wouldn't it be neat to look at the output from a steering position sensor on a bike? I don't really know what it would show, or what it would mean, but it would be neat. I suspect with most riders (even the determined anti-counter-steerers) there'd be a little outwards blip at the start of the corners and a little inwards blip at the end.

Must be a whorthwhile thing to measure....

[Mikkel]

Must be a whorthwhile thing to measure....

You'd have to use force sensitive pads on the handlebars. Your handlebars don't actually move when you countersteer at speed. It's all about the applied force...

[Badjelly]

Your handlebars don't actually move when you countersteer at speed.
Not at all? I'm sure the movements are small but I doubt that they are zero, and I'd like to see the output of a sensor recording them, that's all.

[Mikkel]

Not at all? I'm sure the movements are small but I doubt that they are zero, and I'd like to see the output of a sensor recording them, that's all.

The movement of your handlebars are due to the steering geometry when you lean over the bike - not your input. (Except at very low speeds)

[Sully60]

You'd have to use force sensitive pads on the handlebars. Your handlebars don't actually move when you countersteer at speed. It's all about the applied force...
:Offtopic:
But what component/cause of the bar movements do you think they're measuring here then?

[Badjelly]

The movement of your handlebars are due to the steering geometry when you lean over the bike - not your input. (Except at very low speeds)

I think that when I push on the inside bar (or pull on the outside bar) to initiate a turn, the initial response is for the handlebars (and forks and wheel, of course) to rotate outwards. This causes the bike to lean inwards, at which time further adjustments take place (including, but maybe not confined to, rotation of the bars) and the bike steers around the turn. Are you suggesting that there is no initial rotation of the bars? Then how does the pushing/pulling on the bars have any effect?

Anyway, given your deep understanding of bike steering, could you please tell me what you think a steering position sensor would show as you enter and leave a turn.

[Mikkel]

:Offtopic:
But what component/cause of the bar movements do you think they're measuring here then?

I fail to see what you mean.

But if you want to see how people countersteer you have to look at the steering input from the rider. Not the movement of handlebars.

[Hitcher]

Please refer to post #110.

[MacD]

Or perhaps my post (http://www.kiwibiker.co.nz/forums/showpost.php?p=1387072&postcount=77) in another countersteering thread.

If I was an engineer I'd be heading off to London (http://www3.imperial.ac.uk/controlandpower/research/portfoliopartnership/projects/motorcycles).

[Bass]

However, I'd have to see something more substantial than a vague claim, with no references, that someone has proven gyroscopic forces not to be a major factor in the mechanics of motorcycles before I'm willing to accept it.
Because, as you say, the theory is neat and tidy - not easily understood in a compound 3D environment - but still it is pretty much bullet proof.
..

That's entirely fair and is also the major failing of my side of the discussion so far.
However I'm on dial up in Oz this week and it's just too effing slow for me to do any serious research

[Ixion]

Or perhaps my post (http://www.kiwibiker.co.nz/forums/showpost.php?p=1387072&postcount=77) in another countersteering thread.

If I was an engineer I'd be heading off to London (http://www3.imperial.ac.uk/controlandpower/research/portfoliopartnership/projects/motorcycles).

Well, that is VERY interesting.



A comprehensive study of the effects of acceleration and braking on motorcycle stability with the use of the advanced motorcycle model is presented. The results show that the wobble mode of a motorcycle is significantly destabilised when the machine is descending an incline, or braking on a level surface. Conversely, the damping of the wobble mode is substantially increased when the machine is ascending an incline at constant speed, or accelerating on a level surface. Except at very low speeds, inclines, acceleration and deceleration appear to have little effect on the damping or frequency of the weave mode. A theoretical study of the effects of regular road undulations on the dynamics of a cornering motorcycle with the use of the same model is also presented. Frequency response plots are used to study the propagation of road forcing signals to the motorcycle steering system. It is shown that at various critical cornering conditions, regular road undulations of a particular wavelength can cause severe steering oscillations. The results and theory presented here are believed to explain many of the stability related road accidents that have been reported in the popular literature.


So it's NOT just imagination that bikes handle better on uphill corners than downhill ones. 'it's scientific like.

[Ixion]

The thesis the site links to is even mor einteresting (even if does use bloody LISP - lotsa irritating silly parentheses ). 'Twill take me a few days to wade through it, but some of the conclusions are certainly interesting.

[Hitcher]

Does countersteering work the opposite way in the northern hemisphere?

[Ocean1]

Does countersteering work the opposite way in the northern hemisphere?

Well duh!, obvious innit, they ride on the other side of the road!

[Ixion]

Yes, but the beauty of it is that it is cancelled out by the fact that they also ride upside down (being on the arse end side of the world, n all)

[GSVR]

You'd have to use force sensitive pads on the handlebars. Your handlebars don't actually move when you countersteer at speed. It's all about the applied force...


http://www.kiwibiker.co.nz/forums/showpost.php?p=1387072&postcount=77

Just picked up on the attachment on this post. Confirms what Ive been on about all along. Please read the whole paper.

[ital916]

here is the vid of the no bs bike keith codes made.

http://www.youtube.com/watch?v=3nRUeEkS644

[Mikkel]

So it's NOT just imagination that bikes handle better on uphill corners than downhill ones. 'it's scientific like.

Well, there is no substitute for emperical evidence is there? ;)


Well duh!, obvious innit, they ride on the other side of the road!

And that leaves England, Japan, etc. where exactly? :rolleyes:


here is the vid of the no bs bike keith codes made.

http://www.youtube.com/watch?v=3nRUeEkS644

Yes, that video proves quite readily that you CAN change direction on a bike without steering input to the handlebar (no active countersteer). It also very clearly shows that applying steering input at the handlebar increases the handling characteristics by "a whole lot".

Although I'd have to say he could hang a lot more off that bike when using the dummy bars.


http://www.kiwibiker.co.nz/forums/showpost.php?p=1387072&postcount=77

Just picked up on the attachment on this post. Confirms what Ive been on about all along. Please read the whole paper.

Interesting article - I'll read it properly when I find some time later.
However, from what I just read it very much illustrates the complexity of the whole system and how utterly naive it is to say "this or that is not a (major) factor in [insert appropriate bikie term]".

[hayd3n]

Not true, there's another huge difference between a stationary and moving bike when it come to possible control inputs. YOU"RE MOVING, any change in steering input is effective because it's possible to change the contact patch.

also things like g force and momentum aswell etc

[Mystic13]

You'd have to use force sensitive pads on the handlebars. Your handlebars don't actually move when you countersteer at speed. It's all about the applied force...


So you're saying if we weld the bars in place, then get up to speed and push on the bar, the bike will turn. I think the bike wouldn't turn or would barely turn but only based on the moving of body weight.

Just me thoughts.