Variable Diameter Wheels

[greencactus3]

well offtopic but square wheels would keep the axle movement linear if the ground it were rolling upon was half circles... theres plenty of articles onthat all over the place if you're interested.. like square wheeled bicycles.

waaaaaaaay offtopic but with all the ways people have done and attempted multispeed robots, anyone try a variable wheel diameter? not in the transmission but like the wheel(or w/ tire) that touches the ground... it expands, and itll basically be like a higher gear. and also give more ground clearance... so little junk wont be in the way when its going fast but when it pushes, the center of gravity goes lower andmore torque is applied via smaller diameter wheels.
if you're tricky, you can probably pull that off automatically with some sort of centrifugal system.