Dynamic Traction Characteristics of Tires

Shifting weight forward in a racecar to improve turn in is a known fact. Not only NASCAR and CART crew chiefs use this phenomena but Milliken & Milliken [1]¹, Carroll Smith [2], and other authorities state this fact in books. The “classic” tire side force variation with load curve at a constant slip angle shows side force increases less than load. The “classic” tire side force/load curve, which is real data, does NOT agree with the facts known to crew chiefs AND authorities in the field of tires. A different tire model that includes slip heat generation is used to show that BOTH statements above are correct, but at different times in a corner. The reason for the change in tire traction is heat generated in the contact patch and a change in surface temperature of the tread rubber.