6 pneumatic wheel (AndyMark tires and hubs), drop center, dead axle, #35 chain driven.
Our biggest issue this year is that we went wide instead of long. It made navigating the defenses more difficult than it needed to be. We thought we were being clever by designing our drivetrain so that the wheels would be closer together, but what we didn't factor into our design in our engineer lizardbrains is that we'd be hitting the defenses at high speed. Having some span between the wheels wouldn't have hurt us TOO much and we would have had an easier time of driving quickly. Good thing our driver is pretty flexible
https://drive.google.com/open?id=0B4...TgwWEl5ZzlFZ28
Early picture.
EDIT: Definitely used way too many bearings per axle. Next time, not so many.