[EricH]

Originally Posted by Chris is me

If you're going to assert reality contradicts physics, please at least cite a source of test results or other evidence. Statements of fact without backing like this are how misconceptions are made.

There is a team working on testing this. As such, there are no definitive results yet. It's quite possible that theory and reality agree. But there have been some CD discussions on this topic over the years, which taken together indicate that there is some disparity, due mostly to rubber interacting closely with carpet to give a slight but noticeable increase in traction on a wider wheel.

Remember: Ideal physics tend to take place on a surface with uniform friction (possibly no friction) and in a vacuum unless otherwise specified. There are very few places that have both. Because that sort of place is rare, especially when Murphy is around (or at a robotics competition), reality tends to win over physics by emphasizing those slight differences.