[sanddrag]

Originally Posted by JVN

Some people believe larger wheels increase robot traction, but I still haven't seen any logical reason why this is true. I'm not convinced.

I've heard that too and I wasn't able to figure out any possible reason why someone might think that until just the other day. I won't be convinced until someone throws the scientific method at it but here's why larger wheels might have the potential of increasing traction.

Neither the tread surface nor the carpet is a rigid surface; they are both quite deformable and interlock with each other. If the tread was a rigid surface, and the carpet was a rigid surface, the place where the two meet would be a line. However, this is not the case. Since each can deform, the interface between then is actually something like a small plane, allowing for more bite. Now, take a wheel. Take a very narrow slice out of it, like a slice of pie or pizza. Look at the curvature of the "crust" (tread surface). A larger diameter pizza/pie/wheel will have less curvature than a smaller diameter pizza/pie/wheel. You could say that the slice with less curvature is "flatter" on the crust/tread and that this "flatness" gives it a larger interface plane with which to interlock with the carpet. See, as diameter approaches infinity, curvature approaches zero (flatness).

I have no idea if any of the above is true, but it sounds probable.