[Aren Siekmeier]

You will want to take another look at your gearing.

Also, going along with Akash's remark, with the C-channel it looks like you are only supporting your wheel axles at one point. You will want at least two. For this and other structural reasons I would suggest box tube in place of the c-channel. It comes in various sizes (1"x2", 1"x1", etc.) and wall thicknesses (no less than 1/8" for a drive base usually) and can be found at (perhaps donated by) your local metal shop. Quite a few teams (including my own) use it structurally, and you can either weld or rivet (with gusset plates) the joints.