02-11-2008, 12:05 AM
The rule is 15% slip angle is optimal on dry pavement.
As I'm heading for some ice racing (but not with the 968 and its summer tires), I've been thinking and wondering why slip angles are some much larger in dirt, snow and ice. I'm also guessing the slip angles on ice must be less than snow or dirt. Does anyone here have a good explanation?
My vague theory is that it's related to the ratio of the coefficients of static and dynamic friction. The lower the ratio the greater the slip angle. There's also the effect of the spinning of the driving wheels which can forward force. BTW, if 15% slippage is optimal on dry pavement what is the optimal slippage on snow or ice?
On snow I can expect sideway (perpendicular) tire movement to build up a snow mound that will eventually give some control. On ice once the car starts to rotate there will be very little friction available to stop the angular momentum.
I guess I can wait to get on the ice and figure things out...
As I'm heading for some ice racing (but not with the 968 and its summer tires), I've been thinking and wondering why slip angles are some much larger in dirt, snow and ice. I'm also guessing the slip angles on ice must be less than snow or dirt. Does anyone here have a good explanation?
My vague theory is that it's related to the ratio of the coefficients of static and dynamic friction. The lower the ratio the greater the slip angle. There's also the effect of the spinning of the driving wheels which can forward force. BTW, if 15% slippage is optimal on dry pavement what is the optimal slippage on snow or ice?
On snow I can expect sideway (perpendicular) tire movement to build up a snow mound that will eventually give some control. On ice once the car starts to rotate there will be very little friction available to stop the angular momentum.
I guess I can wait to get on the ice and figure things out...