How much lean angle have I got?

[Oldfulla]

Hi all,
How do you know when you are running out of lean? Please don’t say it’s when you ass off into the ditch you have run out of lean, or look at your tyres and the size of your chicken strips and you will get an idea of how much more you have.

What I want to know is how do you know when you are max lean while you are riding? Is there gradual sliding or woobing that starts, or is there sudden release of grip and you do a big power slide or what?

The reason I ask this is because I have favourite piece of road that I love to ride on. It has some very nice corners that I can go ripping through. I have worn my back tyres to the edge on this road and the bike is rock solid. The bike still feels like I like can lie it down further. Although I don’t fancy putting this to the test on a public road with lots of traffic coming in the opposite direction and end up a skid mark on the road through failed testing.

Does my bike have more lean then I have balls to find out?

Cheers

[MVnut]

Sorry mate few too many variables, but generally with todays tyres (if in good nick) you can lean at least till the bodywork/pegs touch down:cool:

[Patch]

Hi all,
How do you know when you are running out of lean? Please don’t say it’s when you ass off into the ditch you have run out of lean, or look at your tyres and the size of your chicken strips and you will get an idea of how much more you have.

What I want to know is how do you know when you are max lean while you are riding? Is there gradual sliding or woobing that starts, or is there sudden release of grip and you do a big power slide or what?

The reason I ask this is because I have favourite piece of road that I love to ride on. It has some very nice corners that I can go ripping through. I have worn my back tyres to the edge on this road and the bike is rock solid. The bike still feels like I like can lie it down further. Although I don’t fancy putting this to the test on a public road with lots of traffic coming in the opposite direction and end up a skid mark on the road through failed testing.

Does my bike have more lean then I have balls to find out?

Cheers
Depends if ya sticking out ya knee when rounding the curves plus a shitload more things that can change.
But so long as ya bike has USD's I wouldn't worry about lean angles on the road, you'll be sweet as.
Book a place at Taupo 4th April here (www.motott.co.nz/bookings.html) only safe place to learn that stuff. If ya lean to far, you ain't gonna get run over by Pop whose ambling off to the dairy.

FYI: Michelin say 51.2º lean angle in the dry and 43º in the wet for their Pilot Powers - grab a protractor, is interesting

Keep it real.

[CookMySock]

[...] generally with todays tyres (if in good nick) you can lean at least till the bodywork/pegs touch down:cool:REALLY!? Hot diggity dawg I'm gunna try it !! :headbang:

DB

[JimO]

REALLY!? Hot diggity dawg I'm gunna try it !! :headbang:

DB

you have to be moving though or else you will fall over:dodge:

[Taz]

Also remember that the contact patch of your tyre is about the size of your palm so even if you are getting to the edge of the tyre you'd still contacting the road with a good 1/4 to a 1/3rd of the tyre.

[MVnut]

you have to be moving though or else you will fall over:dodge:

Now that's a good call:banana::niceone:

[riffer]

I've always looked at the tyres for an idea of how far I can go. I tend to have a hard line about 3mm wide, with bits of roughed out wear to the edge coming off it. And my pegs have almost never touched down.

However, no matter how far I pull them in, the feet always seem to. So the bike will go further over I guess.

In the end, if you're riding comfortably and as fast as you need to, what does it matter? Worrying about chicken strips is about as important as worrying about the size of your knob.

[DEATH_INC.]

What I find is you feel the front get really vague as it reaches the end of it's grip, it feels like it isn't attached to the road, and the bars start to feel lighter. The rear is a bit harder to feel, it just sorta stops following the front and swings outwards. If ya got it nailed it'll normally start to weave a bit before it lets go completely.
Sometimes though they just go with no real warning....
At least that's what I've noticed.

[Oldfulla]

What I find is you feel the front get really vague as it reaches the end of it's grip, it feels like it isn't attached to the road, and the bars start to feel lighter. The rear is a bit harder to feel, it just sorta stops following the front and swings outwards. If ya got it nailed it'll normally start to weave a bit before it lets go completely.
Sometimes though they just go with no real warning....
At least that's what I've noticed.

sweet thanks for that answer DEATH_INC., thats what I'm wanting to know, not saying that any of the relpies weren't good as they were. I think maybe I may have worded my question slightly wrong.

Cheers
oldfulla

[Usarka]

sweet thanks for that answer DEATH_INC., thats what I'm wanting to know, not saying that any of the relpies weren't good as they were. I think maybe I may have worded my question slightly wrong.

Cheers
oldfulla

The trouble is until it actually goes for the first time then you're never sure exactly how far it's got to go...... the question is how bad do you want to find out.....

[Ocean1]

FYI: Michelin say 51.2º lean angle in the dry and 43º in the wet for their Pilot Powers - grab a protractor, is interesting

Did exactly that. :yes:

Got a cargo strap around the garage rafter and leaned it over to 45deg, scary. Then leaned it to the 55deg Mr Buell says is max. Is a good way to scare the crap outa oneself.

[beyond]

Too many variables to be definite.
Size and weight of the bike and rider.
Condition and type of tyres.
Condition and type of surface.
How smooth you ride as ham fisted riding will get you tossed in no time at all.

On most road tyres when you have gone too far you generally don't get time to correct before you are down and out.

On "most" bikes you will more than likely touch down the peg feeler bolts easily enough with room to spare. If harder bits touch down then that's a loss of downforce which is probably going to have you off pretty quick as well.

When your rear goes at speed you are stuffed 9 times out of 10. It goes so fast that if you manage to correct it it you will more than likely highside (hurts a lot) but will mainly lowside which still hurts.

[BadCompany]

I can scrape my pegs on my GPX250 and I still have small chicken strips on the front but nothing on the back, might chuck a bigger wheel on and see if I can get her lower :D

[Macstar]

As mentioned, bike chasis, attachments is usually the limit. I recently bought a new Hornet 900 and scrape the pegs often. I have also scraped away some of the rear brake lever too. Having said this, I've owned a lot of bikes and the only other bike that I got scraping action on was the KTM motard.

The tyres will reveal how much more you've got to go though.

[Grub]

might chuck a bigger wheel on and see if I can get her lower :D

Front tyre isn't your dick ... bigger isn't better. Just stick to the manufacturer's specs, that what their supercomputers and test riders have found makes your bike handle and stay planted best

[sAsLEX]

FYI: Michelin say 51.2º lean angle in the dry and 43º in the wet for their Pilot Powers - grab a protractor, is interesting



Seen that young stoner get 70 degrees at Laguna Seca, so you can go rather far!

[BadCompany]

Front tyre isn't your dick ... bigger isn't better. Just stick to the manufacturer's specs, that what their supercomputers and test riders have found makes your bike handle and stay planted best

Sorry I was referring to the back tire. I still have a little chicken stripes on the front, but nothing on the back. So I'm thinking if I get a bigger back wheel and get lower, I can find the max of the front wheel.

[Grub]

Sorry I was referring to the back tire. I still have a little chicken stripes on the front, but nothing on the back. So I'm thinking if I get a bigger back wheel and get lower, I can find the max of the front wheel.

Same applies to the back. There was a really big thread on this about 8 days ago woth lots of technical background. See if you can find it. It basically comes down to this ...

The tyre and the rim size are matched. If you put a wider tyre on the existing rim then it has to wrap around in a smaller circle to fit the narrow rim. This can make your tip-in feel really weird (either too fast or too slow) and if you really get it wrong you end up with less tyre contact patch rather than more.

Then there's the relation of the rear tyre's width to the front. Mis-matched and they don't have the same roll into the corner which means you could end up with bad understeer or oversteer, I can't remember which. The geometry of a bike is hugely complex with castor, trail, dip and all sorts of other parameters all designed by those big computers to work together - I wouldn't change a thing

[jcupit69]

Time to head to a track day :niceone:

[koba]

Sorry I was referring to the back tire. I still have a little chicken stripes on the front, but nothing on the back. So I'm thinking if I get a bigger back wheel and get lower, I can find the max of the front wheel.

It will also go a wee bit faster with the right tyre on it.
Less contact, less weight = Less resistance Therefore more power to ground.

Not scientific, just reasoned in my brain.
My VFR now handles MUCH better with the standard 130 on the back instead of the 140 that had been wrapped around it.

[jcupit69]

Front tyre isn't your dick ... bigger isn't better. Just stick to the manufacturer's specs, that what their supercomputers and test riders have found makes your bike handle and stay planted best

Agree, worn my back down right to the edge and untill i get new pegs it cant go over further (even then the back isnt really able to go over any more), and iv still got lil strips on my front

[enigma51]

Sorry I was referring to the back tire. I still have a little chicken stripes on the front, but nothing on the back. So I'm thinking if I get a bigger back wheel and get lower, I can find the max of the front wheel.

Dont try and concentrate on how far you lent over if you manage to go around the corner you have the required lean angle thats realy all that counts

[scumdog]

In the end, if you're riding comfortably and as fast as you need to, what does it matter? Worrying about chicken strips is about as important as worrying about the size of your knob.

A fact that too many choose to ignore - and the younger the rider the more they ignore it. <_<

[TerminalAddict]

As mentioned, bike chasis, attachments is usually the limit. I recently bought a new Hornet 900 and scrape the pegs often. I have also scraped away some of the rear brake lever too. Having said this, I've owned a lot of bikes and the only other bike that I got scraping action on was the KTM motard.

The tyres will reveal how much more you've got to go though.

one of the many wonders of motorcycling.
I too own a hornet.
I have reached the edge of my rear tyre plenty of times.
I ain't no slow poke.... but I'm no casey stoner either, there are much faster riders I ride with.
and the wonder bit .... I've had stuff touch down , maybe 3 times in 2 years

maybe I hang off more than your something

[Mikkel]

Seen that young stoner get 70 degrees at Laguna Seca, so you can go rather far!

That's on state-of-the-art racing slicks - slightly different game :yes:

In the end it's about cornering, not leaning. The sharper you can corner at less lean the better! This is the argument for hanging off your bike. If you hang off properly your knee should touch the ground before your peg feelers. Having your knee down gives you a very good feel for how far over you're leaned and adds a bit of stability (at least psychologically).

That being said, I'd suggest practicing that black art on a track - not the public road.

[Ocean1]

In the end it's about cornering, not leaning. The sharper you can corner at less lean the better! This is the argument for hanging off your bike.

This interests me. Talk about lateral G forces at the contact patch and how hanging off the bike changes them. Or is it just a technique to stay inside the tyre's lean angle spec's?

[vifferman]

Oldfulla - if you really want to know how far you can lean, then you need to take it to and just past the very limits a few times, like Mr Rossi did. Once you've learned what it feels like when you've gone just past the limits, then you don't have to crash so often.
Seriously, if you're not prepared to crash while exploring the limits of your bike and your cornering abilities, then I suggest you stick with being contented with tyres that have no 'chicken' strips (or, as I like to call them, "margins of error").

[Mikkel]

This interests me. Talk about lateral G forces at the contact patch and how hanging off the bike changes them. Or is it just a technique to stay inside the tyre's lean angle spec's?

When you lean your bike over two things happen: You change the steering geometry of the bike (slightly, due to trail) and you move your centre of mass (COM) off the centerline of the bike.

The more you change the steering geometry (more lean, longer trail) and the more you move your COM off-center the faster you will turn. (Faster turning equals larger lateral forces.)

By hanging off your bike you move your COM off the centerline without leaning the bike. This allows you to corner faster at a lower lean angle. This is of course only important if you're pushing the bike to its (and its tyres) limits. I'd expect a tyre to loose grip rapidly if you lean it beyond what its profile is designed for.

Also, remember that a long trail makes the bike handle less sharply - but provides good stability while cruising. (Think sportsbikes that needs steering dampers vs. hogs)

[onearmedbandit]

Hence why you see racers in the wet hanging completely off the bike despite moderate lean angles.

[Ocean1]

By hanging off your bike you move your COM off the centerline without leaning the bike. This allows you to corner faster at a lower lean angle.

Yes, explain what effect it has on lateral G given the same speed.

[Macstar]

one of the many wonders of motorcycling.
I too own a hornet.
I have reached the edge of my rear tyre plenty of times.
I ain't no slow poke.... but I'm no casey stoner either, there are much faster riders I ride with.
and the wonder bit .... I've had stuff touch down , maybe 3 times in 2 years

maybe I hang off more than your something

Yeah, my riding mates tell me I should hang off the bike more but I can't really be shagged. My developed style (good or bad), is shifting my weight to the pegs and maybe scootling my ass a little to the side that I am leaning, but I don't hang off the side of the bike, hence the peg scraping.

I read in "the Pace thread" that riding this way gives the appearance that you are going slower than you really are - cause you're not dragging a knee along the ground etc. and therefore good for calming/tricking other motorists and cops.

Good suspension set up will also of course avoid a lot of peg scraping action too - which you may have BTW!!

[xwhatsit]

Yes, explain what effect it has on lateral G given the same speed.

None, of course, but I think what people are trying to say is that with a shallow lean angle your bike has a higher limit for lateral G.

[Mikkel]

Yes, explain what effect it has on lateral G given the same speed.

If you're cornering with a given acceleration the lateral forces are identical. For the same acceleration (think circular motion) you will corner with a tighter radius if you are going slower.

What changes by hanging off your bike is vectors describing the forces acting on the bike.

See the attached image. Notice the difference in displacement between contact patch and center of mass for the guy sitting upright and the guy hanging off the bike - lean angle is identical. (I apologise for my lacking drawing skills...)

[avgas]

In a perfect world the bike goes down and lightly scrapes the pegs like a dish cloth on a fry pan and we all ride away like nothing really happened (only done it once on ZX4).
But sad reality is peg grabs NZ chunky tarseal and the see-saw happens lifting the weight off the wheels.

[Mental Trousers]

Yeah, my riding mates tell me I should hang off the bike more but I can't really be shagged. My developed style (good or bad), is shifting my weight to the pegs and maybe scootling my ass a little to the side that I am leaning, but I don't hang off the side of the bike, hence the peg scraping.

I read in "the Pace thread" that riding this way gives the appearance that you are going slower than you really are - cause you're not dragging a knee along the ground etc. and therefore good for calming/tricking other motorists and cops.

Good suspension set up will also of course avoid a lot of peg scraping action too - which you may have BTW!!

That sort of style is much better suited to road riding because you don't jump around as much. On the road it's only extreme cases where you need to climb way off the bike and stick a knee out, and that's only cos you screwed up or something unexpected has happened.

As for finding the edge of the tyres, my old girl would often start to feel vague in the front end (much like Death_Inc says) and she'd start to get get a small shake through the bars. On the Michelins it was very obvious when I'd ridden off the edge of the tyres as the whole bike would gently slide sideways the further I leant over. That was 1 of the reasons why I always use matched tyres - you get to the edge of them both at the same time. The Metzelers and Super Corsa Pro's I never found the edges.

[Ocean1]

If you're cornering with a given acceleration the lateral forces are identical. For the same acceleration (think circular motion) you will corner with a tighter radius if you are going slower.

What changes by hanging off your bike is vectors describing the forces acting on the bike.

See the attached image. Notice the difference in displacement between contact patch and center of mass for the guy sitting upright and the guy hanging off the bike - lean angle is identical. (I apologise for my lacking drawing skills...)

So, in spite of the separation of body and bike mass centrelines available lateral traction is unaffected, up to the point where leaning in will prevent the tyres exceeding their design limits.

If manufacturers develop tyre profiles and compounds which optimise traction at extreme angles are you not reducing available traction by keeping the bike more vertical? Doesn’t it make more sense to attempt to keep the bike on an angle where the tyres perform best?

[Mikkel]

So, in spite of the separation of body and bike mass centrelines available lateral traction is unaffected, up to the point where leaning in will prevent the tyres exceeding their design limits.

If manufacturers develop tyre profiles and compounds which optimise traction at extreme angles are you not reducing available traction by keeping the bike more vertical? Doesn’t it make more sense to attempt to keep the bike on an angle where the tyres perform best?

I'd say no to that.

I believe some road tyres use a harder compound in very narrow lean angles and have a softer compound for wider angles. And I guess this would make sense.

However, if you look at Stoner leaning in at 70° - that is pretty extreme to me. I doubt that racing slicks will have anything but soft compound rubber on them.

The way to look at it is this: The tyre grip (compound, design) does not dictate how fast you corner - it dictates how fast you CAN corner - i.e. how much lateral force you can apply to the road for a certain normal force. As you lean over further your normal force decreases since the weight is not sitting "on top" the contact patch. There fore, the more upright you can keep your bike for a given cornering speed the less risk you have of loosing grip.

[xwhatsit]

So, in spite of the separation of body and bike mass centrelines available lateral traction is unaffected, up to the point where leaning in will prevent the tyres exceeding their design limits.

I would guess that's not quite right. Your suspension would surely be working better with a shallow lean angle -- when you're leaned over, bumps are trying to shift the suspension up and down at a different angle to what it works at. So if you're more upright, your suspension can keep the wheels in better contact with the road, right?

[Mikkel]

I would guess that's not quite right. Your suspension would surely be working better with a shallow lean angle -- when you're leaned over, bumps are trying to shift the suspension up and down at a different angle to what it works at. So if you're more upright, your suspension can keep the wheels in better contact with the road, right?

There is that as well. Hitting a significant bump while on a lean upsets the bike much more than when upright.

We're talking riding on a theoretical flat surface here I assumed... ;)

[Badjelly]

As you lean over further your normal force decreases since the weight is not sitting "on top" the contact patch. There fore, the more upright you can keep your bike for a given cornering speed the less risk you have of loosing grip.

That sounds dodgy to me, Mikkel. What do you mean by normal force? Normal to road? For a horizontal road, that's just the weight of the bike + rider.

[ipod1098]

skidmark will know. he scrapes his fairings..

[FROSTY]

One thing not mentioned (I think) is that every tyre brand and within reason model has its own way of "announcing" its about to start to slide.
For example Michellen tends to go vague fairly early and slide progressively whereas Metzlers grip longer but let go with more of a bang.
--The tyre "experts" dont knot knickers :girlfight: these are examples only

[AllanB]

Did exactly that. :yes:

Got a cargo strap around the garage rafter and leaned it over to 45deg, scary. Then leaned it to the 55deg Mr Buell says is max. Is a good way to scare the crap outa oneself.

The thing here is that when riding you have your weight etc on the bike - looks cool in the garage but differs on the road. I presume the tyre guys lean angles are actual riding ones, otherwise they are pointless.

[Mikkel]

That sounds dodgy to me, Mikkel. What do you mean by normal force? Normal to road? For a horizontal road, that's just the weight of the bike + rider.

For a vertical bike on a horizontal road... yes.

Trouble is what happens at the contact patch when you are on a lean?

Not all of your weight is pushing directly down on the tyre - some is being balanced by gyroscopic forces as well.

[Ocean1]

The way to look at it is this: The tyre grip (compound, design) does not dictate how fast you corner - it dictates how fast you CAN corner - i.e. how much lateral force you can apply to the road for a certain normal force.

Yup.


As you lean over further your normal force decreases since the weight is not sitting "on top" the contact patch. There fore, the more upright you can keep your bike for a given cornering speed the less risk you have of loosing grip.

Can’t see that, the combined “normal” (1G vertical) and centrifugal forces maintain balance exactly over the tyres contact patch, or you fall over, no matter what the angle. The normal gravitational component isn’t a variable, (“normally”) and we’ve already established that there’s no advantage in changing the angle of the tyres wrt the road surface unless it’s to avoid over-leaning. I can easily see that being useful on a track, I just don’t see how it produces any advantage up to that “max tyre angle” point.


I would guess that's not quite right. Your suspension would surely be working better with a shallow lean angle -- when you're leaned over, bumps are trying to shift the suspension up and down at a different angle to what it works at. So if you're more upright, your suspension can keep the wheels in better contact with the road, right?

Arguably one of the things that can detract from suspension performance is lateral load, which can increase friction and slow response speeds. Hanging off the bike produces exactly such loads. Bear in mind the suspension “see’s” movement perpendicular to the bike’s vert centreline, it don’t care what lean angle you’re on.


The thing here is that when riding you have your weight etc on the bike - looks cool in the garage but differs on the road. I presume the tyre guys lean angles are actual riding ones, otherwise they are pointless.

Suspension compressed or not doesn’t affect the angle, 55deg is 55deg whatever weight is on the bike. It will affect ground clearance…

[enigma51]

One thing not mentioned (I think) is that every tyre brand and within reason model has its own way of "announcing" its about to start to slide.
For example Michellen tends to go vague fairly early and slide progressively whereas Metzlers grip longer but let go with more of a bang.
--The tyre "experts" dont knot knickers :girlfight: these are examples only

Bridgestones are good that way they always slide and I like very much

[Mikkel]

Can’t see that, the combined “normal” (1G vertical) and centrifugal forces maintain balance exactly over the tyres contact patch, or you fall over, no matter what the angle. The normal gravitational component isn’t a variable, (“normally”) and we’ve already established that there’s no advantage in changing the angle of the tyres wrt the road surface unless it’s to avoid over-leaning. I can easily see that being useful on a track, I just don’t see how it produces any advantage up to that “max tyre angle” point.

I can see your argument. I am sorry but I can not provide you with an answer. There must be a reason for why you would want not to lean your bike over more in low-grip situations though.


Suspension compressed or not doesn’t affect the angle, 55deg is 55deg whatever weight is on the bike. It will affect ground clearance…

I'd dare say that it is more complicated than that. What could be treated as a 2D system (bike upright traveling straight ahead) becomes a 3D system when you introduce lean. Hitting bumps would be more likely to cause you to loose grip when you are on a lean I'd bet.

[Badjelly]

That sounds dodgy to me, Mikkel. What do you mean by normal force? Normal to road? For a horizontal road, that's just the weight of the bike + rider.


For a vertical bike on a horizontal road... yes. Trouble is what happens at the contact patch when you are on a lean?
Not all of your weight is pushing directly down on the tyre - some is being balanced by gyroscopic forces as well.

Once you're settled into the corner (and assuming there are no undulations in the road and ignoring tidal forces etc etc etc) then the COG of the bike + rider will not be accelerating up or down, therefore the weight of the bike + rider will be balanced exactly by the vertical component of the force exerted by the road at the tyre contact patch (or fairing contact patch, if you're Skidmark). Well, actually, a bike has two wheels, so I should have said the sum of the vertical components of the forces exerted by the road at the tyre contact patches.

By "gyroscopic forces" I assume you mean the forces required to change the axis of rotation of the wheels, or in other words, to change the orientation of the wheels' angular momentum vectors. These aren't accelerating the COG of the bike + rider, so they don't affect the total force at the contact patch (or the sum, see above). However they might affect the front-rear balance.

Racers clearly do lean off a bike to decrease the lean angle of the bike itself. There are various reasons this might be useful.

Use tyre nearer to centre
Avoid scraping stuff
More stable to bumps
Don't have to move the bike so far laterally on corner entry and exit
Allows contact of knee with surface, giving feedback

[Badjelly]

we’ve already established that there’s no advantage in changing the angle of the tyres wrt the road surface unless it’s to avoid over-leaning.

I'm not sure about that. It's not like a tyre is a wooden block with some rubber of the bottom, where the maximum lateral force it can sustain depends only on the coefficient of friction of the rubber. Tyres flex. This lets them do all sorts of interesting things like (I think) creeping across the road before they let go entirely. Perhaps tyres just work better at smaller lean angles.

[Ocean1]

I can see your argument. I am sorry but I can not provide you with an answer. There must be a reason for why you would want not to lean your bike over more in low-grip situations though.

In so far as I can be said to have a position on the matter it would be that there's a particular angle where a given tyre will provide maximum grip, and that that's the angle one should try to maintain regardless of that required to navigate a corner. That may well mean hanging of the inside when you're pushing the limit. It also means hanging off the outside on slow turns, although there's no point in doing so.

I am aware that body english seems somewhat to be influenced by things other than simple physics, fashion for example. Not that long ago it was rare to see racers moving so far inboard as most currently seem to, and even now some hardly move at all, with no apparent loss of cornering speed. Moving body weight around on a dirt bike has more effect but for reasons which mostly don’t apply to road bikes… then again, look at motards, and ask yourself why they do it all backwards.


I'd dare say that it is more complicated than that. What could be treated as a 2D system (bike upright traveling straight ahead) becomes a 3D system when you introduce lean. Hitting bumps would be more likely to cause you to loose grip when you are on a lean I'd bet.

Yup, significant front wheel vert displacement through a hollow mid-corner messes up the geometry big time.

[Ocean1]

Racers clearly do lean off a bike to decrease the lean angle of the bike itself. There are various reasons this might be useful.

Use tyre nearer to centre
Avoid scraping stuff
More stable to bumps
Don't have to move the bike so far laterally on corner entry and exit
Allows contact of knee with surface, giving feedback


All entirely believable.


I'm not sure about that. It's not like a tyre is a wooden block with some rubber of the bottom, where the maximum lateral force it can sustain depends only on the coefficient of friction of the rubber. Tyres flex. This lets them do all sorts of interesting things like (I think) creeping across the road before they let go entirely. Perhaps tyres just work better at smaller lean angles.

Be nice to have an expert confirm or deny eh?

Either way we're talking minscule differences, the wide range of tyre profiles and the variation in different rider's body english suggest any advantage is small enough to be inconsequential at the speeds I ride at.

[Mikkel]

In so far as I can be said to have a position on the matter it would be that there's a particular angle where a given tyre will provide maximum grip, and that that's the angle one should try to maintain regardless of that required to navigate a corner. That may well mean hanging of the inside when you're pushing the limit. It also means hanging off the outside on slow turns, although there's no point in doing so.

Unless there is a variation of the tyres compound across the width of the tyre you should be able to gain the most amount of lateral force from that tyre, before it looses grip, in the totally upright, vertical position.


I am aware that body english seems somewhat to be influenced by things other than simple physics, fashion for example. Not that long ago it was rare to see racers moving so far inboard as most currently seem to, and even now some hardly move at all, with no apparent loss of cornering speed. Moving body weight around on a dirt bike has more effect but for reasons which mostly don’t apply to road bikes… then again, look at motards, and ask yourself why they do it all backwards.

The clearance of modern sportsbikes for lean angles are much greater than they used to be. It's fairly easy to scraped the peg on my '89 zxr250 - I would imagine it would be much more difficult on a modern fireblade or something like that.

Motards are very different. Their center of mass is much higher compared to sportsbikes - this gives more displacement between COM and contact patch for the same lean angle without hanging off.
Furthermore these bikes are much lighter with smaller wheels and they have a huge lean clearance...

[Ocean1]

Unless there is a variation of the tyres compound across the width of the tyre you should be able to gain the most amount of lateral force from that tyre, before it looses grip, in the totally upright, vertical position.

Why would you assume that?

Firstly, a lot of modern tyres do indeed have stickier compounds on the sides.
And secondly the sectional profile of most tyres is not a perfect arc, in fact some have a pronounced triangular section. So there is likely to be both a significantly larger contact patch and a higher COF at the designed optimum angle.


Motards are very different. Their center of mass is much higher compared to sportsbikes - this gives more displacement between COM and contact patch for the same lean angle without hanging off.
Furthermore these bikes are much lighter with smaller wheels and they have a huge lean clearance...

And yet they typically lean OUT. Benefit of the doubt: it’s ingrained dirt riding behaviour, still, even when not sliding it seems not to detrimentally affect their corner speeds…

[jrandom]

Worrying about chicken strips is about as important as worrying about the size of your knob.

Hey, I worry a lot about the size of my knob.

[Ocean1]

Hey, I worry a lot about the size of my knob.

And the profile... aaand the squidgy compound on the sides...

[jrandom]

And the profile... aaand the squidgy compound on the sides...

And the fast wear rate...

:laugh:

[FROSTY]

Ohh ffs--iff ya lean till ya feel enuff--aint that enuff-- if ya wanna experiment go to th track

[Ocean1]

And the fast wear rate...

:laugh:

Perilously close to that P word there dood...

[Badjelly]

Hey, I worry a lot about the size of my knob.


And the profile... aaand the squidgy compound on the sides...

And the lean angle!

[Ocean1]

And the lean angle!

Y'know, that might well explain why some of our more well endowed members report more difficulty with LH or RH corners.

You, dude, dress left or right?

[Badjelly]

You, dude, dress left or right?

I lean to the right.

[Mikkel]

Firstly, a lot of modern tyres do indeed have stickier compounds on the sides.
And secondly the sectional profile of most tyres is not a perfect arc, in fact some have a pronounced triangular section. So there is likely to be both a significantly larger contact patch and a higher COF at the designed optimum angle.

First of all - there's only two things that determine the size of the contact patch - tyre profile is not one of them.

To determine the size of your contact patches in square inches you take the weight, in pounds, carried by each tyre in any given circumstance and divide it by the tyre pressure in PSI. It is that simple.

Yes, if the compound varies across the width of the tyre, indeed the coefficient of friction (both kinetic and static) will vary with lean angle. I just said that let's consider it constant in order to determine the impact of lean up the amount of lateral force the tyre can carry.

[Ocean1]

First of all - there's only two things that determine the size of the contact patch - tyre profile is not one of them.

To determine the size of your contact patches in square inches you take the weight, in pounds, carried by each tyre in any given circumstance and divide it by the tyre pressure in PSI. It is that simple.

That would certainly be the case if tyres were completely non-rigid, a completely non-structural pressure barrier.

But they aint.

[Kickaha]

First of all - there's only two things that determine the size of the contact patch - tyre profile is not one of them.


Are you saying for a given rim size the profile of the tyre won't alter how much contact patch there is? eg from a 60 to a 70

[Oldfulla]

Oldfulla - if you really want to know how far you can lean, then you need to take it to and just past the very limits a few times, like Mr Rossi did. Once you've learned what it feels like when you've gone just past the limits, then you don't have to crash so often.
Seriously, if you're not prepared to crash while exploring the limits of your bike and your cornering abilities, then I suggest you stick with being contented with tyres that have no 'chicken' strips (or, as I like to call them, "margins of error").

thanks for the reply.
I dont mind exploring the limits of my bike and tipping off to find them out, it isnt the falling off that worries me so much. its the sudden stop or hitting something hard at the end of the fall. Also I really really dont want to damage my bike, that is the biggest factor that has held me back.
maybe with some more track time in the future and some money I can really push things.

[Mikkel]

That would certainly be the case if tyres were completely non-rigid, a completely non-structural pressure barrier.

But they aint.

Of course - that is indeed the ideal world I am describing. However, it's still a very fair approximation to what you'd see in the real world. Tyre pressure and weight are the two main factors that determine the size of the contact patch.


Are you saying for a given rim size the profile of the tyre won't alter how much contact patch there is? eg from a 60 to a 70

Ideally it wouldn't. I am not saying you wouldn't be able to see a difference between two tyres - real life is incredibly complicated if you start going into detail :yes:

If you want to go in detail you have to consider:

Softness of the tyre compound.
Softness of the surface on which the bike is situated.
Temperature.
Humidity.
Topology of the surface on which the bike is situated.
Local variations in the gravitational acceleration due to variations in the composition of the earths mantle.

And the list goes on...

To retain the KISS principle I postulate that tyre pressure and weight supported by the tyre are the two only important factors when determining the size of the contact patch. (But ultimately it doesn't matter - calculating the size and shape of the contact patches for a bike in motion is not currently doable... and let's face it, if the bike isn't moving who gives a fuck anyway?)

[Mental Trousers]

thanks for the reply.
I dont mind exploring the limits of my bike and tipping off to find them out, it isnt the falling off that worries me so much. its the sudden stop or hitting something hard at the end of the fall. Also I really really dont want to damage my bike, that is the biggest factor that has held me back.
maybe with some more track time in the future and some money I can really push things.
Best way to explore the limits of your tyres is to either take it to a track or go find a carpark and start going around in circles. You'll either scrape shit on the ground or find the limits of the tyres.

I think you've guessed by now that you can safely ignore the engineering geeks cos even if you can figure out what they're saying they have conflicting views anyway.

And for the engineering geeks, suspension is less efficient at larger lean angles, a bike can only lean so far so getting the riders weight inside the line of the bike lets you go around corners quicker and the more upright a bike is the less likely a momentary loss of traction is going to spit the rider off.

[90s]

Best way to explore the limits of your tyres is to either take it to a track or go find a carpark and start going around in circles. You'll either scrape shit on the ground or find the limits of the tyres.

+1 Yep. I don't want to remember a big "thump" after someone sliding towards me as I come around a corner because they have been playing skidmark on the public roads trying to find the limits of tyre grip thanks.

There is only one way to find the ultimate limit and that is to push until you crash. But whilst you learn on a track what it feels like, on lumpy tarmac on a public road you might find it is not quite the same at all.


Best way to explore the limits of your tyres is to either take it to a track or go find a carpark and start going around in circles. You'll either scrape shit on the ground or find the limits of the tyres.

I did do that as a teenager (as teenagers do) in a closed school roadway with a roundabout (a nice little track set-up really) at a weekend. The result after leaning and leaning was BANG with me on my bum and the rear wheel of the bike spinning madly and oil & petrol leaking out of it having scraped the mint red plastic work.
Obviously there was some red damage on me too.
I wouldn't recommend it really, esp. as it was Dad's bike. :mad:

[Ocean1]

That would certainly be the case if tyres were completely non-rigid, a completely non-structural pressure barrier.

But they aint.


Of course - that is indeed the ideal world I am describing. However, it's still a very fair approximation to what you'd see in the real world. Tyre pressure and weight are the two main factors that determine the size of the contact patch.

Some in the industry seem to have discovered another factor...

"The Storm ST is the first tire to include Avon’s new "Reactive Footprint" technology. This technology marries Avon’s unique variable belt density carcass with Lifetime Profile Engineering to produce a footprint which changes size and shape, depending on the bike’s lean angle, for the full life of the tire.

The result is a contact patch that grows as the bike leans, giving more grip in corners while minimizing wear rates when travelling in a straight line."

Interesting... http://books.google.co.nz/books?id=akcdioKmRk8C&pg=PA14&lpg=PA14&dq=motorcycle+tire+contact+patch+photography&source=web&ots=CzCKwnxmZt&sig=itx2PhkZo_1xy45ekEsUggWwIGI&hl=en#PPP1,M1

[Ocean1]

Best way to explore the limits of your tyres is to either take it to a track or go find a carpark and start going around in circles. You'll either scrape shit on the ground or find the limits of the tyres.

I agree, in fact I believe the only way is to repeatedly crash on a range of surfaces, at different speeds, pressures etc etc.

Not keen eh.


I think you've guessed by now that you can safely ignore the engineering geeks cos even if you can figure out what they're saying they have conflicting views anyway.

And for the engineering geeks, suspension is less efficient at larger lean angles, a bike can only lean so far so getting the riders weight inside the line of the bike lets you go around corners quicker and the more upright a bike is the less likely a momentary loss of traction is going to spit the rider off.

Ignore away dude. The function of discussions like this have little to do with actual riding, it’s about better understanding our wee bit of the world, and sometimes a new way of doing things transpires which really does make a difference in the real world.

Edit: and thanks for the last bit there.

[Mikkel]

Some in the industry seem to have discovered another factor...

"The Storm ST is the first tire to include Avon’s new "Reactive Footprint" technology. This technology marries Avon’s unique variable belt density carcass with Lifetime Profile Engineering to produce a footprint which changes size and shape, depending on the bike’s lean angle, for the full life of the tire.

The result is a contact patch that grows as the bike leans, giving more grip in corners while minimizing wear rates when travelling in a straight line."

Interesting... http://books.google.co.nz/books?id=akcdioKmRk8C&pg=PA14&lpg=PA14&dq=motorcycle+tire+contact+patch+photography&source=web&ots=CzCKwnxmZt&sig=itx2PhkZo_1xy45ekEsUggWwIGI&hl=en#PPP1,M1

Very interesting.

However, it is not the size of the contact patch that determines what friction you have available! That depends only on the normal force and the coefficient of friction.

Generally the size contact patch - but not the shape - is proportional to the amount of normal force (weight on the tyre) and inversely proportional to the tyre pressure.

As the attached image illustrates, the contact patch will change with lean angle - but whether it just changes shape or it actually changes size is a bit hard to tell. As we have established above the softness of the tyre compound may have *some* influence upon the size of the contact patch - so yes if you change the compound across the tyre profile you may observe slight variations of the size of the contact patch depending upon the lean angle.

I won't question that you can design a tyre that will have more grip at lean than in the upright position. However I would argue that it is a matter of variations in the coefficient of friction - not because the contact patch changes.

Also, I'd always be rather skeptic of marketing hype if you want to understand basic principles.


Ignore away dude. The function of discussions like this have little to do with actual riding, it’s about better understanding our wee bit of the world, and sometimes a new way of doing things transpires which really does make a difference in the real world.

Indeed - this discussion doesn't make any difference in how well we ride our bikes. It probably won't have any effect whatsoever - I still find it interesting to discuss such matters though.

Thinking is hard though and some people generally frown upon it. That's ok, we don't force anyone to participate.

[Badjelly]

However, it is not the size of the contact patch that determines what friction you have available! That depends only on the normal force and the coefficient of friction.

So that's it, then. All those wide tyres that people cram onto bikes (and cars) don't make a damn bit of difference. Someone better tell the MotoGP tyre designers. <_<

Rubber tyres are complicated beasts, and their performance is not adequately described by a single number called "coefficient of friction". Having said that, I must admit I don't understand why wider tyres seem to be better, especially since (as you've pointed) they don't necessarily result in a large contact patch than narrow tyres. But it does seem to be true that wider tyres give better performance than narrow ones, within limits.

[Badjelly]

Ignore away dude. The function of discussions like this have little to do with actual riding, it’s about better understanding our wee bit of the world, and sometimes a new way of doing things transpires which really does make a difference in the real world.


Indeed - this discussion doesn't make any difference in how well we ride our bikes. It probably won't have any effect whatsoever - I still find it interesting to discuss such matters though.
Thinking is hard though and some people generally frown upon it. That's ok, we don't force anyone to participate.

Hear hear.

[Mikkel]

So that's it, then. All those wide tyres that people cram onto bikes (and cars) don't make a damn bit of difference. Someone better tell the MotoGP tyre designers. <_<

Rubber tyres are complicated beasts, and their performance is not adequately described by a single number called "coefficient of friction". Having said that, I must admit I don't understand why wider tyres seem to be better, especially since (as you've pointed) they don't necessarily result in a large contact patch than narrow tyres. But it does seem to be true that wider tyres give better performance than narrow ones, within limits.

There are heaps of advantages from using wider tyres. One of the main things is heat dissipation - the same bit of rubber doesn't get "used as much".

Also, stability during high lateral forces.

A wider contact patch also means that you use more of the road surface...

This is especially true for cars. Motorcycles are slightly different of course, but some of the same things are applicable.

[Mental Trousers]

It's interesting that people think that doing low speed circles in a car park in more likely to result in a bin and therefore is scary. Carparks and similar areas (the odd disused runway, closed roads etc) are where the majority of rider training takes place. The object of doing circles is not to get your knee down etc. It's to get used to having a bike leaning over and knowing what it feels like. If you lean over far enough you'll find out what it's like to get near the limits of your tyres. Don't know how exploring the limits at 30kph is dangerous or scary.

[Ocean1]

However, it is not the size of the contact patch that determines what friction you have available! That depends only on the normal force and the coefficient of friction.

So you’d expect to see little or no difference in traction over a wide range of tyre pressures?

COF varies not only with the tyre compound characteristics but with the road surface, there’s a compromise between local compound deformation and contact area to be optimised, that’s why realfastdudes mess with the pressure depending on which surface they’re on. In fact the compromise is way more complicated than simple COF considerations, tyre deflection is much less controled than the suspension so it's likely that running higher pressures than those required for optimum static friction pays dividends.



I won't question that you can design a tyre that will have more grip at lean than in the upright position. However I would argue that it is a matter of variations in the coefficient of friction - not because the contact patch changes.

Wonder if there’s any benefit to be had by compartmentalising carcases to allow different pressures across the tyre width… Doubt it, progressive compounds probably already provide whatever advantages can be had there. Think there’s still way more to be had from compound development though, and real-time reactive suspension.

[Ocean1]

It's interesting that people think that doing low speed circles in a car park in more likely to result in a bin and therefore is scary. Carparks and similar areas (the odd disused runway, closed roads etc) are where the majority of rider training takes place. The object of doing circles is not to get your knee down etc. It's to get used to having a bike leaning over and knowing what it feels like. If you lean over far enough you'll find out what it's like to get near the limits of your tyres. Don't know how exploring the limits at 30kph is dangerous or scary.

But I don’t think that. And I agree that such practice, (with expert advice) is good for finding that “near the limit” point. I think such post-novice, non-racing focused training would be great, is it available?

[Mikkel]

So you’d expect to see little or no difference in traction over a wide range of tyre pressures?

COF varies not only with the tyre compound characteristics but with the road surface, there’s a compromise between local compound deformation and contact area to be optimised, that’s why realfastdudes(TM) mess with the pressure depending on which surface they’re on. In fact the compromise is way more complicated than simple COF considerations, tyre deflection is much less controled than the suspension so it's likely that running higher pressures than those required for optimum static friction pays dividends.

I never argued that the COF was a constant. :nono:
Indeed COFs are bloody complicated. It is however quite possible to establish a rough estimate if you know the surface materials and temperature of the two relevant surfaces. If you want detail you have to consider micrometer-scale geometry which for all intents and purposes are beyond the scope of any real considerations.

Again, if we include too many variables it quickly becomes extremely difficult to discuss even the most simple scenarios.

But yes, tyre pressure is very important too. Some people don't even think of tyres as being part of the suspension setup - although they play a crucial part.

[90s]

If you lean over far enough you'll find out what it's like to get near the limits of your tyres. Don't know how exploring the limits at 30kph is dangerous or scary.

Because the discussion has been to find the limit by going too far and crashing, which is often the only true way to establish where the real let-go point is. Which is dangerous and scary, even in controlled conditions. And I don't recall any posts mentioning that this should be at 30kph. When I leaned to bin it was at about 60kph that I found how far I could lean on a tight mini-roundabout before the bike went down.
And worse than dangerous and scary, exspensive. And pointless to, unless you are a funded track-racer to be honnest.

[Mental Trousers]

But I don’t think that. And I agree that such practice, (with expert advice) is good for finding that “near the limit” point. I think such post-novice, non-racing focused training would be great, is it available?
Most post-learners courses cover that sort of thing if people request it, with many others doing that or something similar as standard. Learning what the bike feels like near it's limits is very important for safe riding. The courses I've done in the past (both for riders and for instructors) have covered this sort of thing.

[Oldfulla]

Mental-Trousers,
what are the courses that you have done in the past that addresses what a bike feels like when it is pushed to its limits? I would be interested in something like this. Who runs them?

btw, this thread is getting to be a long read, but a good discusion. Interesting to see all the different and varying views out there, thanks to all who have contributed


Cheers

[onearmedbandit]

+1.

This thread is a good example of motorcycling discussion still very active on KB. Notice how those that say KB is only full of crap now are noticeable by their absence.

Back to your normal program.

[Brett]

AS already noted, how long is a piece of string? Too many variables to give a definitive answer.

[Mikkel]

AS already noted, how long is a piece of string? Too many variables to give a definitive answer.

Nah, there's a pretty big difference...

With the string question there is one unknown variable - which could easily be calculated if you knew e.g. the mass, the material and the thickness of said string.


However, with regards to the discussion in this thread there are too many, interconnected variables that will change dynamically as the bike moves.

And yes, this is irrelevant, you are right - I'm just being a contrary bastard ;)

[onearmedbandit]

AS already noted, how long is a piece of string?


Nah, there's a pretty big difference...

With the string question there is one unknown variable - which could easily be calculated if you knew e.g. the mass, the material and the thickness of said string.




See, that's the thing with you engineer type guys, too complicated. That one unknown variable could easily be found with a ruler. Or tape measure.

[Ocean1]

See, that's the thing with you engineer type guys, too complicated. That one unknown variable could easily be found with a ruler. Or tape measure.

:Oi: I is simple.

Besides, if at any stage questions are being asked about the length of a bit of string you don't need a tape, it's not long enough. Murphy's law y'know.

[CookMySock]

If you lean over far enough you'll find out what it's like to get near the limits of your tyres. Don't know how exploring the limits at 30kph is dangerous or scary.Its just that everything happens much more quickly at low speed. At 100clicks in a sweeper, lines can be adjusted with a tiny bar push and they feel very controllable - and I guess they can be at 30clicks too, but the bars feel lighter it seems to be less stable.

That is all unfortunate, coz 100clicks in a sweeper is not exactly the place for a noob to have a brain fart. Though, the same brain fart at 30k will drop your bike - it just won't kill you as well.

DB

[Mikkel]

See, that's the thing with you engineer type guys, too complicated. That one unknown variable could easily be found with a ruler. Or tape measure.

Troll! :p

And of course Ocean1 is correct about Murphy's law - it's the 0th law of thermodynamics! :yes:

And I'll just keep quite about the fact that you just reapply the ruler/tape measure the necessary number of times to complete the measurement...

[90s]

:Oi: I is simple.

Besides, if at any stage questions are being asked about the length of a bit of string you don't need a tape, it's not long enough. Murphy's law y'know.

Now Murphy knew all about testing the limits until meltdown. He was a rocket-sled tester. They were probably less safe than they sound.

Unless you are Murphy, play it safe.

But as I am on that tip, I have to post my favourite Murphy story. One of his teams tested 'plane cockpits for birdstrike. Thy developed a cannon that fired a chicken at the glass. They leant it to a well-known 'plane manufacturer who phoned up totally furious - "your damn cannon nearly killed someone - the chicken smashed through the cockpit, ripped through the lenght of the plane and lodged in the rear bulkhead".

"Well, next time defrost the chicken ..." :rolleyes:

[Ocean1]

And of course Ocean1 is correct about Murphy's law - it's the 0th law of thermodynamics! :yes:

And I'll just keep quite about the fact that you just reapply the ruler/tape measure the necessary number of times to complete the measurement...

One thing generally little understood about Murphy's Law is that it was not actually coined by Murphy, was another dude with the same name.

O'flanagan's corollary (to Murphy's Law): "Murphy was an Optimist."



Now Murphy knew all about testing the limits until meltdown. He was a rocket-sled tester. They were probably less safe than they sound.

Unless you are Murphy, play it safe.

Nichols' Fourth Law: "Avoid any action with an unacceptable outcome."


I have to post my favourite Murphy story. One of his teams tested 'plane cockpits for birdstrike. Thy developed a cannon that fired a chicken at the glass. They leant it to a well-known 'plane manufacturer who phoned up totally furious - "your damn cannon nearly killed someone - the chicken smashed through the cockpit, ripped through the lenght of the plane and lodged in the rear bulkhead".

"Well, next time defrost the chicken ..." :rolleyes:


Stapp's Paradox: "The universal aptitude for ineptitude makes any human accomplishment an incredible miracle."

<>

[onearmedbandit]

"Well, next time defrost the chicken ..." :rolleyes:

Well I saw a mythbusters episode where they tested both frozen and unfrozen chickens and found no difference. They were expecting a difference.

[Mikkel]

Anyway, I think we have to bring this thing back on-topic...

I dare say that trying to establish your maximum lean angle before loosing grip would most likely only provide proof for Murphy's Law. :yes:

[90s]

Anyway, I think we have to bring this thing back on-topic..

So that's the way this internet is meant to work?

In the real world finding the absolute limit of your tyres, and trying to 'feel' for the edge of the grip envelope is totally species anyway, because what today in the sun = grippy melting tarmac tomorrow = early dew on cold metal. If there are too many variables to factor in for the theorectical max lean for tyres, imagine factoring in the total number of pertinent external environmental factors - after all the contact patch connects to something ...

[Mental Trousers]

what are the courses that you have done in the past that addresses what a bike feels like when it is pushed to its limits? I would be interested in something like this. Who runs them?

Most of the training courses I did were 12-15 years ago so I'm not sure who or which courses you'd need to take. However, check what your local rider training school offers and ask questions. Usually that sort of stuff is part of the advanced road rider training.

[discotex]

Well I saw a mythbusters episode where they tested both frozen and unfrozen chickens and found no difference. They were expecting a difference.

I thought they re-tested that in one of their "viewers complained we didn't test it fairly so we're doing it again" episodes and found that indeed frozen packed more punch.

[henry]

On my Hyosung I could scrape the foot pegs and the side stand bracket without running out of grip, as long as the road was smooth.

[Skyryder]

When sparks come off the rims you know that you have gone too far. :bye:

Skyryder

[Kendog]

Did exactly that. :yes:

Got a cargo strap around the garage rafter and leaned it over to 45deg, scary. Then leaned it to the 55deg Mr Buell says is max. Is a good way to scare the crap outa oneself.

Did you take a picture of that?

[Ocean1]

Did you take a picture of that?

No.

Easy enough to do though.

Why?

[Kendog]

No.

Easy enough to do though.

Why?

I am really curious to see what a road bike looks like at that angle.

[Ocean1]

I am really curious to see what a road bike looks like at that angle.

Looks... improbable.

Will acquire pic when I've got a bit of spare time eh? and workshop space, bit tight at the mo.

[Kendog]

Looks... improbable.

Will acquire pic when I've got a bit of spare time eh? and workshop space, bit tight at the mo.

Sweet thanks, or next time you go for a ride let me know and I can take a picture of you.

[Ocean1]

Sweet thanks, or next time you go for a ride let me know and I can take a picture of you.

Dude, 55 deg on the Buell is grazing the wee feeler thingies on the footrests.

Considering Mr Michelin's limit is well short of that and that there's a discernable chicken sliver on the rear I doubt I've ever been within half a foot of that.

But if you promise to hold the cargo strap I'll give it a go eh?

[xgnr]

I was told I went faster (than my mate) round twisties cos I had skinnier tyres... just goes to show that it ain't that simple. :eek5:

[Mikkel]

I was told I went faster (than my mate) round twisties cos I had skinnier tyres... just goes to show that it ain't that simple. :eek5:

Ususally you only go faster around the corners than your mates because either a) you have bigger balls and/or b) you have less appreciation for the unexpected.

[CookMySock]

On my Hyosung I could scrape the foot pegs and the side stand bracket without running out of grip, as long as the road was smooth.

Which Hyosung ? What tyres on it ?

TIA,
DB

[henry]

Which Hyosung ? What tyres on it ?


GT250R with the stock tyres. I found the biggest problem with loosing grip was the front suspension not being able to keep the tyre on the road over bumps.

[CookMySock]

GT250R with the stock tyres. I found the biggest problem with loosing grip was the front suspension not being able to keep the tyre on the road over bumps.Well done for exploring those 'limits'. It seems their effort in lightening the front with USD forks is undone by the heavy brakes, wheel, and shocks.. or else the shocks need a serious rethink. Still, an awesome bike.

I have my GT650R suspension set on the softest settings possible, yet it is still too firm, and jittery as over rough ground. Maybe a lighter oil in it..

Also my rear shock seems stuck on a middle setting - to tight to move it with the included tool.

Is it possible to completely revalve or replace these shocks with quality aftermarket gear without breaking the bank ?


cheers,
DB

[henry]

Well done for exploring those 'limits'. It seems their effort in lightening the front with USD forks is undone by the heavy brakes, wheel, and shocks.. or else the shocks need a serious rethink.


I didn't find the handling too bad on the 250. Apart from the aforementioned front end problem. The rear was pretty firm which was annoying but didn't cause any problems in the corners.

The suspension copes ok with the power output of the bike, which is bugger all, hence me trading up yesterday.



Is it possible to completely revalve or replace these shocks with quality aftermarket gear without breaking the bank ?


Dunno. Just buy new bike :)

[discotex]

Well done for exploring those 'limits'. It seems their effort in lightening the front with USD forks is undone by the heavy brakes, wheel, and shocks.. or else the shocks need a serious rethink. Still, an awesome bike.

I have my GT650R suspension set on the softest settings possible, yet it is still too firm, and jittery as over rough ground. Maybe a lighter oil in it..

Based on my limited understanding of the black art of suspension.....

If you have rebound damping set to minimum and compression damping to minimum you should have a pretty plush ride. At least until you hit a big bump at which point the suspension will fully compress then rebound hard. Wonder if that's what you're feeling.

I'd strongly suggest going back to stock settings unless you weigh like 50kg. Doesn't seem a good idea to be right at the extreme soft end to me.

The GT650R doesn't have preload on the front does it? Depending on your weight you might need a different spring-rate or oil.



Also my rear shock seems stuck on a middle setting - to tight to move it with the included tool.

Is it possible to completely revalve or replace these shocks with quality aftermarket gear without breaking the bank ?


Try a hammer/wood mallet.. Should get it moving :)

Pretty sure it's $$ for anything other than changing oil and spring in the front (if that's even possible). Try PM Robert Taylor or catch him in the suspension section. He knows his shit.

[aff-man]

Lean angle depends on tyres used, body position (weight distribution through tyres), suspensions set up and balls.

My first crash (that was more than 1 km from my house) although was a slow one was because I got to the edge of the front tyre under load and well then wen't a little passed it... woops.

That was a while ago on my zxr250 and i's get that thing pretty far over and never bottomed out anything, couple of other guys were talking about scraping pegs and after following them I saw that thier suspension was basically bottoming out hence thier pegs eing a lot lower and scaping.

on the bigger bikes i've rolled off the front, which jamming a slider into the ground corrected and slid around on the edge of the rear, always exciting and quite scarey the first time I saw a pic of myself with the bike cranked over

[speights_bud]

What I find is you feel the front get really vague as it reaches the end of it's grip, it feels like it isn't attached to the road, and the bars start to feel lighter. The rear is a bit harder to feel, it just sorta stops following the front and swings outwards. If ya got it nailed it'll normally start to weave a bit before it lets go completely.
Sometimes though they just go with no real warning....
At least that's what I've noticed.


yea, i've had that experience, Took dads Gixxer 750 out for a play at Frosty's last track day, and i didnt take the time to settle into the bike, just tried to 'muscle it around', which never turns out well. :stupid:

Death, do you remember me near high-siding right infront of you coming through turn 3 in the Infield? The bike actually threw me almost off, i didnt let go of the bars, my ankle was on the seat and i put my other foot down (rooting my back) to get back on it.

[speights_bud]

The trouble is until it actually goes for the first time then you're never sure exactly how far it's got to go...... the question is how bad do you want to find out.....

my first experience with Front end sliding out was at the hairpin at manfield extended track, i ended up loading up weight on my knee to keep just enough weight on the front wheel to keep it down, and have since while Racing Meekey_mouses RG150 buggered a kneeslider coz the tyres melted and it kept letting go at higgens (im just a fatty i guess:whistle:)


There's a graph thingy i was shown once, where it shows leanangle and speed relative to Friction (grip) and yerp, the more you lean the less speed you are able to carry through a corner, so leaning off the bike allow's the two big gyro's (wheels) to maintain a 'straighter' or more upright/faster line through a corner.

I may be wrong, im a reaction rider, i just move about constantly to keep everything feeling nice and balanced :)

[CookMySock]

If you have rebound damping set to minimum and compression damping to minimum you should have a pretty plush ride. At least until you hit a big bump at which point the suspension will fully compress then rebound hard. Wonder if that's what you're feeling. Greetings discotex. Sorry I didn't see your reply earlier - dunno how I missed that.

Yes, everything set at minimum should be way too soft, but it isn't at all - its rather firm.


I'd strongly suggest going back to stock settings unless you weigh like 50kg. Doesn't seem a good idea to be right at the extreme soft end to me.I wish. If were indeed too soft I would do this.


The GT650R doesn't have preload on the front does it? Depending on your weight you might need a different spring-rate or oil.So it seems. Yours is the first suggestion that ACTUALLY named a part that could be swapped out. :pinch: So I will look into this.


Try a hammer/wood mallet.. Should get it moving :)The bike shop removed it put it in the vise and STILL couldn't move the adjustment. He put the spring compressor on it and moved it to its' lowest setting. Actually, its a lot better than it was - particularly two-up.


Pretty sure it's $$ for anything other than changing oil and spring in the front (if that's even possible). Try PM Robert Taylor or catch him in the suspension section. He knows his shit.Ok. Yes I am looking at changing the springs on the rear - the shop says this should be doable. The front springs - we will get to those next. Yes, I started a thread elsewhere and he participated. Unfortunately there were no solutions offered except to replace the lot with ohlins. Not in my price-range.

Many thanks for your observations. Will keep everyone informed.
Steve

[discotex]

Greetings discotex. Sorry I didn't see your reply earlier - dunno how I missed that.

No worries.


Many thanks for your observations. Will keep everyone informed.
Steve

Looking forward to the updates. Sounds like you're just making the best of what you have eh. Good luck!

[Ocean1]

I am really curious to see what a road bike looks like at that angle.

Been spring cleaning, I can finally see the floor of the gargre.

And I was bored.

1. Mr Buell's recommended limit, 55deg, (note the peg's still 40mm odd clear).
2. Mr Michelin's recommended limit, 53deg.
3. Which looks about right...
4. My normal "laundry-safe" limit, 47-48deg, (according to tyre wear).

[discotex]

Been spring cleaning, I can finally see the floor of the gagre.

And I was bored.


That is cool. Got to be pretty committed to get to 53 degrees!

Guess the peg clearance is ok because the suspension isn't compressed.

[RantyDave]

4. My normal "laundry-safe" limit, 47-48deg, (according to tyre wear).
And, also, some lathe porn in the background.

Dave

[Ocean1]

And, also, some lathe porn in the background.

Dave

It's crap.

That's not quite fair, it's one of the better quality chinese products, and it'll do 95% of what I need to do at home.

It's not in the same class as the big Colchester I sold when I had to condense the workshop to somewhat more domestic dimensions though.

[WRT]

Been spring cleaning, I can finally see the floor of the gargre.

And I was bored.

1. Mr Buell's recommended limit, 55deg, (note the peg's still 40mm odd clear).


The peg may be 40mm clear with no rider attached or cornering G's in force, but I bet it's a different story when you've got it cranked over through a high speed sweeper!

[Ocean1]

The peg may be 40mm clear with no rider attached or cornering G's in force, but I bet it's a different story when you've got it cranked over through a high speed sweeper!

I assume the wee feelers do, in fact represent hard contact at Mr Buell's limit, looks about right eh?

I've certainly never scraped the feelers though, flicked the odd stone with 'em, and that scared me quite enough ta very bloody much.

[racefactory]

This is a great thread but only 2 useful replies as far as i have seen that describe the feeling.

I would very much like to know something more realistic: lean angle in wet. Obviously in the dry, it is pretty much known as long as the bike is not accelerating or slowing down in the turn and therefore using up more traction, modern day tyres will easilly support peg scraping, fairing scraping lean angles.

However, in the wet we (at least i do) pull lean angles closer to the lean limits that are still by miles short of peg scraping and knee downs. In wet racing, you can see they are often going round the bends at same lean as we would on the roads! I would very much like to know how you can feel when you are at maximum lean in the wet as it is far more usual for us to get closer to these ''maximum lean angles'' during wet, than dry. What are the symptons that you are getting close?

Racers use the knee scraping to tell how far they are to the limits but in the wet they seldom get their knee down- therefore how can they tell they are on the edge??

Anyone done any peg scraping in the wet?

Last thing to confuse things further more!!! http://www.youtube.com/watch?v=7OOpE7fBw28 insane....

[boomer]

This is a great thread but only 2 useful replies as far as i have seen that describe the feeling.

I would very much like to know something more realistic: lean angle in wet. Obviously in the dry, it is pretty much known as long as the bike is not accelerating or slowing down in the turn and therefore using up more traction, modern day tyres will easilly support peg scraping, fairing scraping lean angles.

However, in the wet we (at least i do) pull lean angles closer to the lean limits that are still by miles short of peg scraping and knee downs. In wet racing, you can see they are often going round the bends at same lean as we would on the roads! I would very much like to know how you can feel when you are at maximum lean in the wet as it is far more usual for us to get closer to these ''maximum lean angles'' during wet, than dry. What are the symptons that you are getting close?

Racers use the knee scraping to tell how far they are to the limits but in the wet they seldom get their knee down- therefore how can they tell they are on the edge??

the rear or front starts to slip.. it pushs out or lets go, but keeps you upright! :stupid:call it what you will. lean teh fooker just teh same as in the dry.. you soon realise when you've lost or about to lose traction.

Then again, i cannot be held responsible for you not having wets, intermediates or the ability to feel what teh tyres/suspension are doing... thats something you need to learn and something the bike can be tuned to help tell you !


ps.. i rode like a nana in teh wet because the 'let go and not come back' limit/time is a lot quicker than in the dry..!

[racerhead]

When Im getting near the limits of lean and grip in the wet I feel the bike gets alot twitchier or sensitive and then closer to the limit you can start to feel the front or rear and sometimes both tyres starting to slide a little. With most good quality modern tyres they allow you to feel things alot better and rarely just "let go" with no warning unless your being hamfisted with the throttle or body movements. The main thing when riding near the limits is to relax so if the bike does start to slide you wont just freeze which will magnify the problems. Hope this helps

[racefactory]

That really does help man- thanks. Some people have said the bars start weaving/shaking, do you find that also happens?

If only i had some crash knobs i'd love to go out and try this in a car park...

[bungbung]

Mental-Trousers,
what are the courses that you have done in the past that addresses what a bike feels like when it is pushed to its limits? I would be interested in something like this. Who runs them?

Come along to a bucket meet. I'm sure you will be made welcome, and am certain you will find an answer.