Kawasaki Sportsbike Riders Club - Australia - Online Forum

I thought everyone who ever went through a Qride would be aware of this fact they make you ride in a straight line and push at the bars to avoid the instructer who is standing in front of you at the time.

All that leaning hang off is just to make it fall in quicker, I actually found out that pushing at the bars at the corect angle is also very important like get your arms at 90degrees to the bars not 45 degrees in the lazvy upright position.

I still havnt read a twist of the wrist but i have had a bit of a pick at the californian superbike school forum at one stage, I supose thats why you pay the bucks and do the courses so a expert can pick up on your obvious mistakes and hopefully you can corect them.

http://www.superbikeschool.com/bbs/inde ... ct=SF&f=11

Thats a great post,& top replies too
helpfull +++++

I've got the DVD version of Keith's old-school book. It's very good, and slightly humerous.

Countersteering is the most efficient way to make the bike lean over.
Once it's leaned over it turns because the front wheel is uneven on the surface (because of the fork rake) so it "falls flat" with the road and the wheel ends up turned in.

You only 'countersteer' to begin the turn, once the bike's actually turning it's not countering steering.
Obviously there's lots of other ways to make the bike lean all need to fight gyroscopic and/or traction forces so are inefficient. Gyroscopic force maintains a spinning objects position in space, since if you lean the bike over with only your body weight, the bike pivots around where the tyres touch the road, the spinning objects' (wheels, flywheel, engine, etc) position in space must be moved a lot (along the arc of the lean).

So, you counter-steer. Front wheel turns the other direction, so the bottom of the bike moves that way. The middle of the bike (where most gyroscopic forces are focused) doesn't want to move, so the bike ends up leaning.
It's easier to lean like this because the bike only needs to pivot around the center of the bike, and center most gyroscopic forces.
It's easy to rotate something that's spinning, but damn hard to actually move it.
And, it's even easier when you've got some gyroscopic force of your own (the now offset front wheel as it's counter-steering).

This is why children have so much trouble learning to ride bikes, and training wheels make it even worse.
The instant one of those training wheels touches the ground, the bike will turn like a car, as soon as the training wheel comes off the ground, it needs to counter-steer to lean and turn... that messes with kids' heads something chronic

Anyone teach a youngin' to ride a bike atm will find it heaps easier to get a bike that fits good, drop the seat right down and remove the pedals.
Let the kid push themselves around until the get the balance and can roll and turn propperly...
Then remind them about pedalling on the good 'ol 3 wheeler.
Then put the pedals back on and raise the seat a bit and it's a simple act of combining two already developed skills, which kids do easily.
Different on a moto though because of the weight, but trainers on the moto should only be there to catch the bike when they drop it. If they touch the ground during a turn it's just delaying the learning process.

Articles like those are pretty good, and Keith is awesome, but they rarely explain the whole thing coz they don't need to.

There's soooo much to bike physics it will blow your mind.
I've played with my fair share of nerdy RC bikes and robot bikes at uni. Sometimes it's hillarious the crashes that can happen.

Now someone just needs to bring up rear-wheel steering .

Might add too; there's barely any focus on this sort of stuff at the SBS courses, surprisingly little. It's such raw stuff that you just need do it correctly otherwise you're not riding a bike.
The courses focus on plausable 'things' that you can feel and think about easily, and recognise results easily.

I forgot about leaning off the bike too.
Leaning off lets the bike sit more upright and lowers the center of gravity.

I know I don't need my body weight to get it leaned over faster but maybe racers do? Surely it can't make much difference though, at most they'll only get 9ms/s extra 'boost' over. Lower center of gravity would make most the difference.
Also as Sam pointed out in an MSN convo once, hardcore racers use the brakes to lower the bike down a tiny little bit so it can tip in faster. That's so cool

JamesLaugesen wrote:I forgot about leaning off the bike too.
Leaning off lets the bike sit more upright and lowers the center of gravity.

At maximum lean angles, if you are hanging off the side of the bike, the bike is more upright. This ensures that there is a larger contact patch between the rubber and the road. As we all know, more rubber on the road = more grip.

scotty37 wrote:Glen,
he is winding you up m8..

Got me. I'm a knob

aardvark wrote:

JamesLaugesen wrote:I forgot about leaning off the bike too.
Leaning off lets the bike sit more upright and lowers the center of gravity.

At maximum lean angles, if you are hanging off the side of the bike, the bike is more upright. This ensures that there is a larger contact patch between the rubber and the road. As we all know, more rubber on the road = more grip.

It's not really the contact patch.
Because the tyre is curved, when it's leaned over, the inside circumference of the tyre is less than the outside. Like rolling a paper cup along a table, the tyre wants to circle inwards.
That's what gives bike's the "twisting" look when viewed from above powering through corners, combined with the rear wheel sliding out sometimes
Obviously the wheel can't be free to circle inwards as much as the differential wants to, otherwise the rear wheel would sping around in the swingarm. So there is a battle between the inside and outside parts of the tyre & the road, just like a 4 wheeler with no differential.
That's called 'scuffing', it wastes traction and -go figure- scuffs the tyres.
The closer to upright you are, less differential; less scuffing = more available grip.
Maybe more contact patch but that depends on your setup.

Scuffing is why bikes don't lose traction violently when leaned, technically they've already lost traction once leaned, so it's a gradual progresssion. Unless the surface changes or whatever, but that's a different matter.

That's the basis of the "leaning uses some of your available grip" concept, not contact patch.
It's also why downhill mountain bike tyres have almost square-edges; they need to dig in for grip. No matter how many big spikes you have on the side of a curved tyre it will always have crap grip because they fight each other, but, it is a lot more predictable to ride.

This is gotta be the best post on the forum so far.

wow so much info to learn and apply.

great stuff crew

Body lean must work at least a bit....

If you sit upright on your bike, at 100kph.... and let go of the handle bars... then lean left.... you go left... No hesitation, no steering... no loading the pegs... you simple go left...

Ofcourse at that point the bike [b]automatically[b] countersteers... so it gives the perception that you are not countersteering..

If you force a countersteer (which will feel really un-natural) your bike will go in the oposite direction... It is also essential if you want to avoid potholes that you saw at the last moment... You will find a quick countersteer will swing you away and back again in a second (try it, but start small!!!)

Yeah you'll still turn because your body weight makes the bike lean over, it wont/doesn't counter-steer automaticly.

If you wanna conciously use counter-steering in your riding you probably should break up all the parts logically.

"Counter-steering" refers to turning the wheel left, to pull the bottom of the bike left, making the top of the bike go right, so the bike is leaning to the right, then the wheel points right and the bike turns right.

If you imagine the lines of each wheel, you'll see the front wheel actually moves to the left, then 'swings' back around and goes right.
So if you try to dodge something on the road, but aren't quick enough, the front wheel might run directly into the object, or even go around the other side of it.

You also counter-steer to bring the bike upright again, it's the exact same motion, but you end up going straight... so the focus on the topic shouldn't be steering, it should be "countering".

If you need your front wheel to avoid something very, very very quickly, you should turn the bars in the direction you want go to avoid it, not counter-steer. The front wheel will zip away ultra fast, but unfortunatly it will take the bottom of the bike with it, so the bike will lean and need to move back in the direction you didn't want to go, otherwise it will fall over.
OR, if you're a trials bike / acrobat bike freak, you could lean right over in the same direction as the front well and do a crazy front wheel drift kind of thing until it's upright again.

Most people who rode pushies as kids are pretty natural with reactions like that even without knowing.
I'm sure everyone can recall times they've dodged a rock or something very quickly on a pushy and thought "YES! I RULE!" only to smack the rear wheel straight into it a few milliseconds later.
Because, not-coicidentally, if you steer the bike Xcm one way and it leans over, it needs to move Xcm the other way to be upright.

Just watch a kid who sucks at riding a pushy, they wobble a lot, but usually end up directly ahead of where they started.

I pinched this from another site and reproduced it (legally). It's a bit technical in places, but steering a bike is technical

Steering a bike

Jesus, you can tell when it's cold outside

Wooohoo, an official document to support my rambling
Good stuff Steve.

For a really simple example of how body-weight can and does affect your steering , then just bung your girlfriend on the back, and get her to lean the *wrong* way when you go around a corner

This simple demonstration will convince you immediately about the benefits of using your body weight correctly when cornering.

This is a great thread Jonno

cheers
AntiGravityDave

I steer by weighting my foot-pegs (as do most other riders on this site)

Actually, when riding a dirt bike through sand or mud, thats exactly what I do. Keep the front wheel pointed where I want to go, and use presure on the pegs to either slide the rear wheel in behind it, or straighten up after its sliped out on a particluarily soft patch. Road Riding is a tad diferent though