RES4CUE

On MTs it's even more exacerbated when a tire gets out of round due to increased weight of tire.

On MTs you must religiously rotate them to keep tread wearing as evenly as possible.

As to drive shaft, probably not that. When a drive shaft is made, there are minor thinness variances in the metal and it will need to be true. You will usually see little pieces of metal welded on at certain points on drive shaft to balance them like weights on a rim.