Changing it only at the bottom adds complexity: Which side is at the bottom right now? How can we know this; how can we know this in a way that will survive the

Changing it only at the bottom adds complexity: Which side is at the bottom right now? How can we know this; how can we know this in a way that will survive the tough conditions we expect this to be driven in? And then we need to have three separate actuator paths to transform just one part of the wheel. We would also need to deal with the fact that just flattening one side of the wheel would make for a shorter perimeter than that of the circle; the tread is a loop of a constant length, and it needs to be kept fairly taut to function in both wheel and tread mode.