[asid61]

As far as general drive trains go, I would recommend designing a WCD (cantaleivered wheels, drop center, 6 wheels, shifting gearboxes). We made a nice one in the offseason. For this year's bot, however, we simply applied the concepts learned from WCD (slots, tensioning, bearing blocks) and made a standard 4WD that has independently controllable wheels for switching to mecanum or "regular". The WCD gave us a lot of experience for the effort.