tire moving on rim at the track

[Racer Boy]

Hopefully, none if us will experience breaking forces, only braking forces!

Here is my thoughtful and deep theory of why the rear tires move on the rims -

Braking forces are much greater than acceleration or cornering forces, but my guess is that the rears rotate on the rims when accelerating out of a slower corner (the greatest acceleration) and you go over bumps or curbs; something that is going to disrupt the grip. I'm talking about the "flat curbstones" that are often at the exits on the outside of turns.

Think about what the rear tire copes with while exiting a second gear turn - it's gripping the pavement while under (for our relatively low-powered) hard acceleration. As you exit the turn, you ride up onto to the curbing, which normally is not smooth; the curbing has a washboard design. The tire is going through a consistent grip/no grip action, experiencing a rat-a-tat-a-tat of forces to it's sidewall. The tire moves a tiny amount on the rim each time this happens. Do that enough times, and the tire ends up moving on the rim enough to notice.

[ianacole]

Originally Posted by Racer Boy

Think about what the rear tire copes with while exiting a second gear turn - it's gripping the pavement while under (for our relatively low-powered) hard acceleration. As you exit the turn, you ride up onto to the curbing, which normally is not smooth; the curbing has a washboard design. The tire is going through a consistent grip/no grip action, experiencing a rat-a-tat-a-tat of forces to it's sidewall. The tire moves a tiny amount on the rim each time this happens. Do that enough times, and the tire ends up moving on the rim enough to notice.

Hmmmm ... that's a good point. Had not considered that the vibrations could cause slipping.