4 ms·

http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics has all you need to know on the subjec

by aston 15y ago

http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics has all you need to know on the subject.

lutorm 15y ago
I'm not sure I agree with the section on countersteering. It says that "out-tracking", the fact that you steer the wheel out from under the bike, is more important than than gyroscopic precession. For motorcycles on highway speeds, I think this is incorrect. If you've ridden a motorcycle at high speed, you know that the handlebars are basically like buried in solid concrete. With normal steering force, I don't think I deflect the handlebars by anything noticeable. The key is that at high speed, the mere application of torque on a spinning wheel, will make it precess, ie turn around the orthogonal axis. I'm convinced this is far more important (but I'm too lazy to do the numbers now).
- sliverstorm 15y ago
  A motorcycle can be turned at speed two ways. Out-tracking is only one of those ways. (Leaning is the other) However, it is the way that lets you take a deep set most quickly, and can help a lot with tight lines. You may think that you are not out-tracking when you turn at freeway speeds, but remember the amount of necessary out-track decreases as speed increases.
  - lutorm 15y ago
    You may think that you are not out-tracking when you turn at freeway speeds, but remember the amount of necessary out-track decreases as speed increases. If you think that out-tracking is responsible for entering turns at speed, there's an experiment to test this: If the bike leaned by moving the wheels out from under it, the bike should pivot around the center of mass. If you actually look at a bunch of road racers in the twisties, it's abundantly clear that the bikes pivot almost completely around the contact point, not around the center of mass. (Unlike bicycle racers which really do out-track.) Moving the COM without moving the contact point can not be done through wheel forces on the pavement, because they act at the contact point. It's impossible for those forces to lean the bike and move the COM is the same direction. The only thing that can accomplish such a motion is the precession resulting from applying the handlebar torque to the front wheel.

by aston 15y ago

http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics has all you need to know on the subject.

lutorm 15y ago

I'm not sure I agree with the section on countersteering. It says that "out-tracking", the fact that you steer the wheel out from under the bike, is more important than than gyroscopic precession. For motorcycles on highway speeds, I think this is incorrect. If you've ridden a motorcycle at high speed, you know that the handlebars are basically like buried in solid concrete. With normal steering force, I don't think I deflect the handlebars by anything noticeable. The key is that at high speed, the mere application of torque on a spinning wheel, will make it precess, ie turn around the orthogonal axis. I'm convinced this is far more important (but I'm too lazy to do the numbers now).

sliverstorm 15y ago
A motorcycle can be turned at speed two ways. Out-tracking is only one of those ways. (Leaning is the other) However, it is the way that lets you take a deep set most quickly, and can help a lot with tight lines. You may think that you are not out-tracking when you turn at freeway speeds, but remember the amount of necessary out-track decreases as speed increases.
- lutorm 15y ago
  You may think that you are not out-tracking when you turn at freeway speeds, but remember the amount of necessary out-track decreases as speed increases. If you think that out-tracking is responsible for entering turns at speed, there's an experiment to test this: If the bike leaned by moving the wheels out from under it, the bike should pivot around the center of mass. If you actually look at a bunch of road racers in the twisties, it's abundantly clear that the bikes pivot almost completely around the contact point, not around the center of mass. (Unlike bicycle racers which really do out-track.) Moving the COM without moving the contact point can not be done through wheel forces on the pavement, because they act at the contact point. It's impossible for those forces to lean the bike and move the COM is the same direction. The only thing that can accomplish such a motion is the precession resulting from applying the handlebar torque to the front wheel.