Originally Posted by
jonathanb715
And, by definition, circumference equals rollout unless there is slippage going on.
Which circumference? At the center of the tread, or the side of the center, closer to the sidewall, where the circumference is slightly lower? On a partially-squished tire, both the center of the tread and the side tread are contacting the ground. But these have two different circumferences, so slippage must occur.