[sanddrag]

Originally Posted by CyberWolf_22

This year we are using 6 in Colson wheels with aluminum hubs. They are built tough for "Battlebots" but they sure work well for our application. I can barely push our bot sideways. The only problem they are very expensive at $50 a piece and we are using six of them. We ordered them from CNCbotparts.com.

I'm not sure what sort of machining capability you have but the wheels without hubs are available for much less here http://robotcombat.com/marketplace_colsons.html

EDIT: And here are some very similar wheels with hubs for cheap, but the hubs are Delrin.

We have used the 6" ones direct on this motor before in a special project without problems, but it was not a competition robot (did not engage in pushing matches). Also, it should be noted that there were two wheels per motor, one on each side.