[mechanicalbrain]

Has anyone considered a second set of omni wheels (or a ball) in the center of the robot so the weight is evenly distributed. They need not be powered. The other thing I'm curious about is the use of different surfaces. I see some mention of using different materials and I have seen some work done on roller surfaces (the grenade wheels come to mind though I don't think that was for traction) but has anyone really experimented with different surfaces?