[TOPEC]

It prob wont have much of an affect if OP just drove in a straight line, its the turns that would be the cause of the wear. OP not only had to deal with mismatched tires front to rear, but also side to side as well. The difference in the width of the tires would've changed the amount of rolling resistance between side to side causing the differentials to compensate constantly. Yes one could argue that that is the whole point of a differential, is to account for the difference in rolling speeds between tires when turning, for matching sizes. This is wear that the diff shouldnt have seen in the first place if the proper sized tires were put at the right place.