Actually what you said reinforces my theory on what is happening. I told some of the students last night that needle bearings might work better than ball bearings for the loads on the front and rear pulleys. We have a couple of backup options, one being to create an outer plate to take out the cantilever factor; the other being to run wheels instead of the treads. We will discuss our options today. Thanks for the advice, I wish we'd known then what we know now.