[Chris is me]

Originally Posted by thefro526

Larger wheels in a 4WD configuration do help with ramp climbing, specifically due to their increased ground clearance, but they may also cause issues with your COG because they're raising your drivetrain up so much.

Personally, We're leading towards using 6" wheels in an 8WD because it allows us to build a much lower base in addition to having excellent maneuverability. Also, due to the wheel placement and geometry of the frame, the 8WD should have no problems with climbing the bump.

I'd Imagine with proper wheel configuration one could use as small as 4" wheels and still be able to climb the ramp successfully.

I think there are a few prevailing drivetrain ideas, one being a four wheel where one wheel "falls" over the bump, then the high frame prevents the robot from high centering before the second wheel negotiates the ramp, and the more than four wheel approach that lowers the CoG in exchange for putting more of the robot in the air at any one time. I'm suspecting this debate will rage on into the competition season; is the decreased turning (or decreased traction) worth the increased stability of high 4 wheel drive?