Eric,
That was a very thought provoking question, and you got a lot of very good answers. MB Doc was right about tires moving on the rims. This is a problem with racers. You have also reminded me of another thought provoking problem. Take any section of freeway, parkway, beltway, turnpike, or whatever you call it where you live. Millions of commuters are wearing their tires out on these roads. Shouldn't there be like piles of rubber dust lining these roads? where does it go?

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