[sanddrag]

1. The wheels ride roughly centerline with the frame rail, which is 1x2 box tubing (sitting vertically). So, that would put our ground clearance under the frame rail at 1.5". But, we have some other stuff that is a little lower. Final ground clearance will be about 1".

2. We wanted a 5" wheel, for the optimal speed and torque for our robot and strategy. We wanted it lightweight. We wanted a 1/2" bore with a 1/8" keyway. We wanted to use incline conveyor belting tread. We didn't want it to be like every other wheel out there. Find me something that meets that criteria, and we'll buy it. We couldn't, so we made it. Wasn't too difficult for an experienced machinist. Wasn't at all costly either. ~<$15 per wheel in material. These are about 0.3 lb each, not including tread or hold down ring. Pretty light.