Originally Posted by Chris is me

I would call 3" wheels "really that small". On a 2x1 frame, that leaves you with a large span to high center on, as well as at most .625 inches of ground clearance right at the center wheel. We've run 4" wheels on 3" tube in 2011 and while it did clear the bumps in the field, anything other than almost perfectly flat would not have worked for that drive.

Basically - there's a reason they aren't a super viable product. The teams that can handle and wish to use sub 4 inch wheels on their robots are the teams already making their own wheels. I wouldn't assume they'll work in the general FRC case just because it looks nice in CAD.