What's going to happen?

[Mudfart]

Ok, this thread is hopefully going to provide information to noob riders about what happens when you ride bikes. Its not to put people off riding, its to prevent them browning their trowsers, when it does happen.
I was always told, if you are ever going to ride, you WILL come off at some time. It hasn't happened yet, and since my rear wheel slip incident, I'm riding more cautiously.
So, my example and information is as follows: I have just done over 1000kms on my bike and just got restricted now, so I'm very noob.
I was riding to work on the waikato expressway when it started to lightly drizzle rain.
I was cranking on the speed doing about 120kph, when coming over a crest, I hit a huge patch of tar bleed and my revs shot up, loss of traction to rear wheel, and I felt the rear go from left to right. I shut off the throttle, came out of the tar bleed at 100kph, and was all good.
My question to those lifetime riders is, what other funny things can I expect to experience while riding? Also, I understand the rear wheel can move alot, especially on much more powerful bikes, but its always sweet and under control aye?

[Jantar]

.....
I was riding to work on the waikato expressway when it started to lightly drizzle rain.
I was cranking on the speed doing about 120kph, when coming over a crest, I hit a huge patch of tar bleed and my revs shot up, loss of traction to rear wheel, and I felt the rear go from left to right. I shut off the throttle, came out of the tar bleed at 100kph, and was all good......
You were very lucky in that you regained traction while the bike was lined up where you wanted to go. A frequent outcome of shutting the throttle when you lose traction on the rear wheel is a high side get off where you are thrown from the bike. This is often the result if you lose traction while cornering and shut the throttle. A steady throttle and little reaction is much safer. This loss of traction is often just momentary (unless its a long wide tar snake). Just be ready to react quickly if the bike lurches when the rear wheel grips once again.

[Slyer]

I've never had that problem with the rear tyre before. What tyres are you running?
Also remember than just when it starts raining after being fine for a few days is the time when the road is at its slipperiest.

[Eyegasm]

I'm not saying I am a godsend far from it but...

You've only done 1000kms, you were speeding, and it only just started to rain.

Mate you were very lucky. Buy me a lotto ticket will ya, Cheers!

[Ixion]

120 in early rain. Hm. All them cheesecutters there , too. Hm. Very lucky you didn't have to brake hard, wasn't it? Maybe its time to restock the Gene-O-Kleen ("Evolution you can see" - now in the giant economy bottle)

[Mudfart]

well im running the factory kwaka tyres, as the bike is brand new. I figure on that particular patch of tar, it wont matter what bike, or tyres etc you have, its a deadly piece of road. Now when I ride this area of expressway, I am constantly on the lookout for these dangerous areas, and there is a lot of them! God help the guy passing through at night that doesn't know the road. Hurry up and fix it, works infrastructure!
really dodgy, with having the cheese cutters for a barrier too. Almost as if they WANT people to die!
The reason I made this post is because I asked a guy if he has regular experiences with rear tyre slide, and he says it happens a fair bit with wet roads, paint on roads, tar etc..... and he rides like a nanna.

[mynameis]

I am surprised you shut the throttle and didn't come off Brainfart :D

[CookMySock]

I was always told, if you are ever going to ride, you WILL come off at some time. It hasn't happened yet, and since my rear wheel slip incident, I'm riding more cautiously.I am fond of the way of thinking "you will always get what you believe you will get", so I do not agree with your suggestion. Perhaps you are right, but thats not the point.



I was cranking on the speed doing about 120kph, when coming over a crest, I hit a huge patch of tar bleed and my revs shot up, loss of traction to rear wheel, and I felt the rear go from left to right. I shut off the throttle, came out of the tar bleed at 100kph, and was all good.On a 250cc bike? I'd say more like you hit a patch of diesel.



My question to those lifetime riders is, what other funny things can I expect to experience while riding? Also, I understand the rear wheel can move alot, especially on much more powerful bikes, but its always sweet and under control aye?I'm not a lifetime rider, but the exposure you have had to a slide, is a valuable lesson to do nothing and don't panic in a slide.

The more you try and contribute to fixing a slide, the more you are going to make it worse - for the foreseeable future anyway. Perhaps when you have extensive experience in the slide you might no better than your tyres.

The other thing is, most slides are over in the blink of an eye well before even your first arse clench, so it's not like you have much say in it anyway.

Also on the track, you discover that the bike wants to shimmy, slide, and headshake all the time, and pretty much you can just let it, as long as you stay on the bike and don't panic.

Steve

[breakaway]

Have had the rear let loose many times on my GSXR 1000. It's important to try to bring it back under control smoothly. Any sudden control inputs (be it brakes, throttle, lean) when the bike is upset have the potential to end very badly.

[george formby]

Have had the rear let loose many times on my GSXR 1000. It's important to try to bring it back under control smoothly. Any sudden control inputs (be it brakes, throttle, lean) when the bike is upset have the potential to end very badly.

Smooth & balanced. Look how many racers have been flipped off their bikes only to have the bike happily carry on upright down the track. They like being upright & will try their best to stay in that position.
I would say, Mudfart, that if you intend spending a lot of time on a bike then you will often be suprised by what is just out of sight. Always expect the unexpected. The roads are crap & nobody cares about bikes. As a rule, comic strip Super heroes don't ride bike's, they are to dangerous. Keep riding & never stop thinking & learning.

[kiwifruit]

Get yourself on a dirt bike in a paddock and have a play

[avgas]

My recommendation is to find out if you can push your limits with the rear spinning out.
I did and it was the best learning experience I have ever had. It quickly became integrated into my riding and driving

[Ender EnZed]

its a deadly piece of road. Now when I ride this area of expressway, I am constantly on the lookout for these dangerous areas, and there is a lot of them! God help the guy passing through at night that doesn't know the road.

Be very careful if you ever decide to try an actual road.

[george formby]

Get yourself on a dirt bike in a paddock and have a play:yes:

Thats how I learnt, losing the front, the back, both, over the handlebars & covered in mud. Brilliant fun & you become instinctive with balance & control

[Mudfart]

I was told the best way to learn to drive a car and control it, was to do burnouts, handbrakes, donuts etc, I found this was true.
I'm seriously thinking you guys are right, that the same applies to bikes. Perhaps I need to a burnout for starters aye?
I'm also considering doing some kind of riding course, I was hoping for hampton downs racetrack, coz i live real close, but ive been told you need full license to go on it! d'oh!
I reckon doing the stage 1 of corning at california riding school would help loads.

[R6_kid]

All them cheesecutters there , too

Yeh, lucky they didn't jump out and grab him aye!

[Cayman911]

You can expect someone to cut you off, and you brake and nothing happens because its wet, the tyres are locked and you are sliding forward at the same speed you were before you braked :)

using only one of the brakes in the wet is pretty much useless.. but then if someone does cut you off you panic and dont really think about which to use how

[slofox]

On a 250cc bike? I'd say more like you hit a patch of diesel.



Wot 'e said. I would rate it as "unusual" to lose rear wheel traction on even newly wet tar bleed unless you really had the throttle on hard. Specially on a smaller bike. I doubt the SV would do that...maybe I should try it out next time it rains...

[Mudfart]

yeah that was one thing I was thinking with being on a 250cc. It was revving at about 9000rpm in 6th gear.

[Ender EnZed]

yeah that was one thing I was thinking with being on a 250cc. It was revving at about 9000rpm in 6th gear.

That doesn't mean it's making more power than a big bike, it means the engine is working harder. The connection between the rear tyre and the road isn't affected by how hard the engine is working.

[Scorp]

Get yourself on a dirt bike in a paddock and have a play

I heard somewhere that dirtbikers have fewer and less serious crashes than roadbikers and I figured. Either that's because they aren't on the road as much, or they've learned where the limits are and how to manage things when they lose it better.

As a 43 year old noob I think I might look a bit daft starting out in dirtbiking, but I really would like to learn the limits of a bike on something more forgiving than pavement. The paddock sounds like a good idea.

[Ender EnZed]

I heard somewhere that dirtbikers have fewer and less serious crashes than roadbikers and I figured. Either that's because they aren't on the road as much, or they've learned where the limits are and how to manage things when they lose it better.

They're usually going much slower.

[kiwifruit]

As a 43 year old noob I think I might look a bit daft starting out in dirtbiking, but I really would like to learn the limits of a bike on something more forgiving than pavement. The paddock sounds like a good idea.

Nothing daft about it, its the best way to start out

[Mudfart]

That doesn't mean it's making more power than a big bike, it means the engine is working harder. The connection between the rear tyre and the road isn't affected by how hard the engine is working.

But do the revs have something to do with torque, velocity etc...? Coz surely a bigger bike revving lower, putting more torque to rear tyre will have better traction?

[Mudfart]

also, Ive talked with california superbike school, and 6R license holders can ride their 250's on the beginners course.
So im gonna start a new thread asking if any noobish riders want to book it for a day, so we are all in the same boat on the track.
This will really help to learn cornering and control i reckon.

[Ender EnZed]

But do the revs have something to do with torque, velocity etc...?

The revs relate to the torque in that their product is the power. This means that if you had a perfectly flat, horizonstal torque curve (a torque "line" instead) then the power curve would also be a straight line from idle up to the rev limiter.

Velocity is the rate of change of position, dunno where you were going with that "etc...".


Coz surely a bigger bike revving lower, putting more torque to rear tyre will have better traction?:no:

Why? More torque to the rear tyre means the rear tyre would spin more. The traction/friction that exists between a your tyre and the road will be the same regardless of whether your engine is 50cc or 5000cc. The traction will be overcome by a certain amount of power. The tyre-road connection doesn't know where the power is coming from or how fast your engine is revving.

At 9000rpm you had about 22hp going through your back wheel. The same as a ZX10 makes at about 2500rpm. Alright, a ZX10 also has more grip due to being heavier, bigger tyre and such but if the tyre-road connection were the same (and it's not far off) then it would have the same chance of breaking traction on any bit of road at 2500rpm as your bike does at 9000rpm.


Ninja 250 power curve (http://ninja250r.files.wordpress.com/2009/03/dyno-ninja250r.jpg)

ZX10R power curve (http://www.akrapovic.com/typo3conf/ext/user_products/mod1/uploads/products/racing_evolution_exhaust_system_for_the_kawasaki_z x_10r_2010_/kawasaki_zx_10r_2010_complete_rac_evo_.jpg)

[Berries]

I was always told, if you are ever going to ride, you WILL come off at some time.

I'd agree if you are talking about on the track, but totally disagree for road riding. All this phrase does is allow people to make an excuse for falling off, i.e. nothing I could do, bound to happen etc etc. As Mr Bastard said, if you think that way then there is a good chance it will happen. Personally, I think that if someone feels that way it's probably best to get a car because falling off has been known to hurt.


The reason I made this post is because I asked a guy if he has regular experiences with rear tyre slide, and he says it happens a fair bit with wet roads, paint on roads, tar etc..... and he rides like a nanna.

Just take it easy as a new rider, or when you step up to a bigger bike. It's all fairly obvious, there is less grip on a wet road, even less on wet markings or manhole covers. And possums. Pick your lines to avoid them where you can, take it easy on the throttle (and brakes) where you can't. You may still get the odd unexpected slide coming out of a corner in the wet with the power on, but over time you'll learn how much and how fast you can turn the throttle. You can't beat experience, a lot of it is down to miles under the belt, under all conditions.

Never done proper MX but imagine it is a great way to learn about a bikes behaviour at slightly safer speeds with a mildly softer landing. And with luck on somebody elses bike.

[Mudfart]

ok the etc... was me not knowing physics but knowing they are involved and the natural scientific principle in keeping the rubber on the road and your skin off it.
Surely a zx10 is putting more rubber onto the road and therefore will have better traction as my tyres are pretty skinny.
however thanks for explaining the torque curve, that makes sense.
The "I was always told" line is simply that. I have two older brothers who have ridden all their lives, and have come off once or twice each. that little gem of info came from them.
I came across a possum the other morning actually and had to readjust my line, in a corner to avoid it. It was a concern that if i squashed it whilst in the corner, i might lose control, how ever I was shocked to find my new line put me over the centreline.

Im gonna save up and get me some training at hampton downs i think, the riderskills.co.nz place is too far away in te atatu.
Does anyone know any instructors in hamiltron?

[CookMySock]

Learner bikes generally have shit suspension too, and its not unknown to see daylight under their wheels with "spirited" riding. It's not really tunable either - its just that they're cheap.

Even larger, modern bikes often have shit suspension as-standard, and really that has to change if you want to cane it around the place - quality suspension is less about ride quality and more about keeping the tyre surface on the fucking road.

That leads us to consider moving to quality suspension doesn't really do anything for your riding experience, except to jar your stuffed back less often, or enable you to go faster with less sensation of speed - but is that a good thing? I like sensation of speed - I wouldn't insulate myself from it.

So what is the solution?

For me, the answer is to just quit being an arse on a bike, and just enjoy it, before I kill someone that someone near to me loves.

Steve

[Thaeos]

I've heard the 250 Ninjas have craphouse factory tires. That might also have contributed.

[Cayman911]

I've heard the 250 Ninjas have craphouse factory tires. That might also have contributed.

So have i, and it is repeatedly mentioned in most the reviews you can find too.

apparently they are too hard and beginners might find em a handfull

[R-Soul]

That doesn't mean it's making more power than a big bike, it means the engine is working harder. The connection between the rear tyre and the road isn't affected by how hard the engine is working.

A 250cc in 6th gear will not have enough torque to cause teh wheel to break traction (even on tar bleed) unless the surface is VERY slippery. Like someone said- diesel (on paint).

[R-Soul]

The revs relate to the torque in that their product is the power. This means that if you had a perfectly flat, horizonstal torque curve (a torque "line" instead) then the power curve would also be a straight line from idle up to the rev limiter.

Velocity is the rate of change of position, dunno where you were going with that "etc...".

:no:

Why? More torque to the rear tyre means the rear tyre would spin more. The traction/friction that exists between a your tyre and the road will be the same regardless of whether your engine is 50cc or 5000cc. The traction will be overcome by a certain amount of power. The tyre-road connection doesn't know where the power is coming from or how fast your engine is revving.

At 9000rpm you had about 22hp going through your back wheel. The same as a ZX10 makes at about 2500rpm. Alright, a ZX10 also has more grip due to being heavier, bigger tyre and such but if the tyre-road connection were the same (and it's not far off) then it would have the same chance of breaking traction on any bit of road at 2500rpm as your bike does at 9000rpm.

Ninja 250 power curve (http://ninja250r.files.wordpress.com/2009/03/dyno-ninja250r.jpg)

ZX10R power curve (http://www.akrapovic.com/typo3conf/ext/user_products/mod1/uploads/products/racing_evolution_exhaust_system_for_the_kawasaki_z x_10r_2010_/kawasaki_zx_10r_2010_complete_rac_evo_.jpg)

Actually you would be looking atthe torque figures rather than the hp figures, since that is what is going to cause you to break traction. At almost idle, the ZX10 has about 50Nm, going up to about 100 Nm + maximum at high revs.

[For the benefit of Mudfart: This is because it has a large bastard of an explosion going on in each cylinder, and acting on a large surface area (the cylinder's cross section), making it give a big push. Large pressure acting on large area= large force. That large force is translated (by the transmission) from linear movement by the piston to rotational (also called angular) movement , acting backwards at the traction band on the road.

It is the torque figures for bikes /cars that give you an indication of their acceleration (0-100 times). Actually its more the torque to weight ratios.

Power is (mathematically) torque multiplied by angular or rotational velocity. Power is the ability of an engine to maintain high torque to high revs. A problem occurs at high revs in engines because the airflow becomes the bottleneck -you cannot get enough air into - and out of- the engine fast enough to burn with the fuel. So power is actually more of an indication of that engines ability to breathe. And more indicative of the top end speed of the bike as opposed to acceleration.

This is why engines with a small number of cylinders (eg V-twins) have high torque and low power - large capacity cylinders cause high torque, while only two cylinders create large airflow bottlenecks it high revs. And inline fours generally have lower torque but a higher capacity for breathing through four sets of valves and hence high power. And this is why the Triumph Speed Triple has a good combo of torque /power.


Note: sometimes the ignition sequence of a four cylinder can be used to make an inline four behave a bit like a V-twin, with two power pulses acting at the same time or close to each other to give good torque - like the 21010 R1]

The maximum torque for a 250cc is shown at about 12Nm. About a quarter that of the ZX10 at idle. And in 6th gear, the torque is nullified even further by long gearing. Thats why I am surprised it broke away - unless you went over a bump and got a bit airborne, reducing the traction enough to allow it to break away.

[Cayman911]

The maximum torque for a 250cc is shown at about 12Nm. About a quarter that of the ZX10 at idle. And in 6th gear, the torque is nullified even further by long gearing. Thats why I am surprised it broke away - unless you went over a bump and got a bit airborne, reducing the traction enough to allow it to break away.

gotta love the good old ninja 250's with the 24.00 Nm :).

[avgas]

Oh lord. What a bunch of noobs.
I will speak slowly now.......
LEARN TO SLIDE
once you do that it doesn't matter what bike you like - you know how to recover from a slide. Where its on a pedal bandit or 100+Nm 100+kw monster.
I used to love kicking the back out of the old FZ1 (much to carvers fearful looks that I was gonna drop her)..........was the best bike for it. But at 100+kph it got a little scary.
Now I prefer the rear solid as a rock - sliding everywhere.
YEEHAA

[george formby]

I see no reason why you the back would not spin up if you hit something slippy enough. Suffered the exact same thing in Europe where their are HUGE patches of tar seal. In the rain riding sedately at 100kmh at low revs, the bike would spin up on every single bit of tar, some stretches would be close to 70mtrs long & the width of the lane. Only really noticeable by the revs shooting up. No drama's though & kept me very focused.

[Mudfart]

im figuring that you can trust the machinery to do the work, and come out of it still upright. otherwise we would all be in the shit.

[Scorp]

[For the benefit of Mudfart: This is because it has a large bastard of an explosion going on in each cylinder, and acting on a large surface area (the cylinder's cross section), making it give a big push. Lagre pressure acting on large area= large force. That large force is translated from linear movement by teh piston to rotational movement -acting sideways at the traction band on the road. It is the torque figures for bikes that give you an indication of their acceleration. Power is mathmatically torque multiplied by angular velocity. it is teh ability of an angine t maintain high torque to high revs. A problem occurs at high revs in engines because the auirflow becomes the bottleneck -you cannot get enough air into - and out of- the engine fast enough to burn with the fuel. So power is actually more of an indication of that engines ability to breathe. And moreindicative of the top end speed of the bike as opposed to acceleration

For the benefit of me too. Thanks for a great explanation of what torque actually is. :niceone:


The maximum torque for a 250cc is shown at about 12Nm. About a quarter that of the ZX10 at idle. And in 6th gear, the torque is nullified even further by long gearing. Thats why I am surprised it broke away - unless you went over a bump and got a bit airborne, reducing the traction enough to allow it to break away.
Hypothetically, if the rider was 'trying' to induce the slide, as a result of a "wonder what'll happen if I do this" moment of madness, could he get the result Mudfart did?

[R-Soul]

For the benefit of me too. Thanks for a great explanation of what torque actually is. :niceone:

Thanks man - just passing on what my lecturers told me in uni. Albeit with crappy typing...


Hypothetically, if the rider was 'trying' to induce the slide, as a result of a "wonder what'll happen if I do this" moment of madness, could he get the result Mudfart did?

Rriders can do stuff to increase the effective force acting against the traction by lowering the gearing - which is why its easier to break traction in first than 6th.

Or the rider can reduce the traction at the wheel. Traction or friction force is the product of weight and a friction factor (F =W x mu) attributable to the nature of the surface. (Strangely enough, in applied mathematics theory, the size of the tyre has nothing to do with traction. However, in practice, micro effects of the tyre "bonding" to and engaging with more microscpically small formations on the road cause the bigger tyres to offer better traction. )

By reducing the weight on the tyre, the traction can be reduced. Like by going over a bump. This is why braking on the back wheel is largely ineffective when braking heavily - because all the weight moves forward onto the front wheel. The maximum traction on teh back wheel is reduced, and it will start sliding pretty easily when you brake on it because the traction is pretty low.

Traction can also be reduced by having a different friction factor (eg. caused by diesel) , so that the same effective torque at the back wheel overcomes the traction and causes the wheel to break away .

Going with the microscopic effects of bonding and engaging by sticky tires, traction can be reduced by having cold tyres.

[avgas]

im figuring that you can trust the machinery to do the work, and come out of it still upright. otherwise we would all be in the shit.
You should have that kind of faith in the machine - otherwise what happens when it rains. Do you leave the bike at home.
OOHHHH NOESSSS THE WATER HAS DECREASE MY TRaction by 5%.....

[R-Soul]

You should have that kind of faith in the machine - otherwise what happens when it rains. Do you leave the bike at home.
OOHHHH NOESSSS THE WATER HAS DECREASE MY TRaction by 5%.....

I dunno about you , but I subdue my driving by about 50% when it rains fo rexactly that reason.

[R-Soul]

You wanted to know what other hairy situations you can find yourself in. Check out my thread:

http://www.kiwibiker.co.nz/forums/showthread.php/120220-Scary-situation-request-for-advice-and-warning-to-newbies?p=1129681211#post1129681211

Hope it helps.

[Lurch]

OOHHHH NOESSSS THE WATER HAS DECREASE MY TRaction by 5%.....

This man has never ridden a sub 250 in the rain before.

And seriously if you were cresting a hill at 120kph in fresh rain on a learner bike your fucken asking for it.

[R-Soul]

This man has never ridden a sub 250 in the rain before.

And seriously if you were cresting a hill at 120kph in fresh rain on a learner bike your fucken asking for it.

And seriously how do you expect any responses making any sense if you have an avatar like that!? I have come out of my daze and found an entire afternoon missing!

[Lurch]

And seriously how do you expect any responses making any sense if you have an avatar like that!? I have come out of my daze and found an entire afternoon missing!

huh? did you say something? :drool:

Actually i find it funny I have about 7 +vely repped posts almost exclusively due to my Avatar

[Scorp]

Actually i find it funny I have about 7 +vely repped posts almost exclusively due to my Avatar
Here's another one... and I'll keep on kidding myself that.....

(Sorry driffted back to the cheeks again)

..... that I always read your posts cos of their intellectual content

:yes: