Sir,
I should have checked with a straight edge, but I did not. After your post, I checked both wheels against an edge, and found that they were both flat, but with a slightly uneven pattern of wear; The top wheel has a depressed area of about .015" x approx. 1.0" on the right side, the bottom has a similar dip on the left. Curious. Also, the wheels (drums actually) are grooved in shallow spirals which run in both left/right and right/left, sort of like a right handed and left handed thread cut into the same bar. It looks intentional, though I can't guess what the OEM might have had in mind.
Thank you for your advise; I was looking mainly at the belts, now I think I should consider what may be wrong with the machine also.
Tom