MOTOGP » Rossi red hot at Sepang

When Cornering you might notice some riders "hanging off" this is the rider altering the C-G with his body weight, A rider can weigh as much or more of the heavy'est component on a bike,the motor. When at lean, the riders body will shift the C-G to the outside of the bike by hanging off, this effects the way the tyres and suspension work. The energy involved with this is channeled closer to 90' of the road, where as if a rider is perpendicular to the bike whilst learning the energy is channeled to the road at the true angle of the lean encouraging lateral movment.

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Gyro effect, the lighter the weight the less G-effect= more performance, simple.
The weight of the front wheel is crucial. In MotoGp weight is no issue, they use weights to keep the bike at the legal limit, remove the weights and the bikes are too lite for the regs.
So teams use heavy or correctly weighted wheels to take advantage of the gyro effect, you can buy ultra lite CF, alloy, magnesuim wheels that are lighter than the wheel that motgp teams use for road bikes, The diff is road bike weigh 200kg and gp bikes weigh 148kg so they offer top performance for road bike.
A strong gyro effect for a light gp bike offers stabillity.
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The front wheel may "tuck" at speed when exiting a turn under power, a week gyro effect will encourage the "tuck" while a strong gyro effect will counter the force trying to push the tyre under the bike, keeping the front wheel straight and the bike upright and racing.

George Shuttleworth never had a problem with gyro he always had a job

Thanks George. At last a sensible comment.

Morgue..Your analogy is a good one. With arms outstretched spin the bicycle wheel enough to generate the gyro effect then apply a force like leaning your weight to the right on a bike by raising your left arm. What happens(other than the wheel resisting you movement)? Well the wheel does attempt to move depending on how much force you are applying with your arms but the movement is at 90 degrees in the direction of rotation(precession)and it will try to turn right. Spin the wheel in the opposite direction and the wheel will try and turn left but if you ever get into this situation on a bike you are in real trouble. With this rule of physics is why you steer a bike by moving your weight.

Thanks Ace27 for your comments. If you don't ask you don't learn. Morgue's comments re the gyro effect were to help explain chatter.
Your comment re the front wheel of a MotoGP bikes is interesting. Do they change the weight or weight distribution of the front wheel as a tuning aid depending on what type of corners there are on a circuit(ie; one with many changes of direction as opposed to one with long sweeping corners where early throttle application is needed for quick lap times)?

Ace, interesting on the heavy wheels bit... I can honestly say I'd never heard that before as it goes against every reason I can think of for using lighter wheels, better acceleration, braking, handling, better ratio of sprung to unsprung weight.

And could you describe what you term as "tuck" as it must be completely different to what I know as "tuck" as the only way to tuck the front as I know it is off the throttle, or a neutral throttle.. caused either by trail braking, falling off the side of the tire or bumps (and the tuck is where, as you loose the front, the inner handlebar comes back towards you so you basically understeer.... always a fun one to catch... by applying throttle)

Thanks Morgue / thanks CA / thanks Ace - interesting read..

Still more confused would a heavy front wheel or anything heavy between the ground and the spring become unsprung weight which I believe is bad for handling???? Thanks CA your explanation made me come up with the reverse gyro wheel or two as nobody said it wouldn't work do you think I should take out a patent???or was it tooooo stupid to answer???
JH bad post,,,,What are you doing answering the Johnny come lately idiots and ignoring the regulars