[IKE]

We did a larger wheel (8") for less intrusion into the chassis when going over the bump. The cost of this was not being able (initially) to do the style of collector we wanted. We then found a work around for this. The larger wheels do have larger wheel torques for the same tractive effort and thus could actually cause you to flip over easier. Do the free body diagrams, and you will find many compelling reasons to go small. We did large to have a smoother motion over the bump.