[evolution]

I'm having trouble locating the " urethane roughtop" on the McMaster-Carr website, that Mr. Andy Baker reffered to above. I checked page 1091 of the online catalog, where the other two are located, but couldn't find this material. Anyone know where to find it?

Also, last year, our team found that our 4 outer wheels, which had SBR wedge-top material, had two much lateral traction (this was really evident when we turned, the robot would wobble and hop). So:

1)Would it seem logical to drop down to urethane roughtop on the outer wheels to reduce lateral traction?
2)Would SBR roughtop perhaps have less lateral traction than SBR wedgetop, although it has greater in-line traction?