4" vs. 6" vs. 8" wheels. Advantages?

[Kevin Sevcik]

Originally Posted by billbo911

So now for an odd addition to the question(s):

Since wider wheels do seem to improve traction so much, and smaller diameter wheels seem to have a decent advantage over larger diameter wheels, what happens if we go to extremes a bit? Say, a 3" wide X 3.5" dia. wheel with rough-top. Would there be enough variation in the speed of the wheel, from it's inner edge to it's outer edge, while turning the robot, to be a problem?

That's going to depend on the width of your wheelbase, but at first glance, I'm doubting it will matter. The narrower your wheelbase the worse it will be, but the narrower your wheel base, the worse problem you'll have simply scrubbing the wheels sideways when turning. So I think if you had things narrow enough for that differential velocity to matter, it'd still be dominated by the much larger force required to scrub your wheels. It's certainly an interesting problem to consider though. I might try throwing some physics at it tonight to help me sleep before kickoff.