[JesseK]

I really like this approach to bumpers and mounting. For a pre-season prototype the most significant advantage of it I see is the ability to change wheel size without re-designing things for ground clearance or field obstacles. This should allow for some fast Day 0 answers.

Personally I'd adjust only one thing about the bumper system, and that would be to add a "wall" (like half of a 3"x1.5" C-channel, probably only 1" length) at the very center of the front & rear rails in order to give the upper part of the bumper some support against hard collisions. As it stands, it seems like the bumper would flex a lot if hit in the middle by a team whose bumpers were not at the lowest possible point of the bumper zone.