Two years ago I had a nail in the rear passenger tire....The dealer has me put whole new rear set on. WInd the clock forward and now I have a nail in the rear driver side. SO my thinking is to take the two good left and right tires and use them. THe only issue is one tire has 9/32 tread and the other is 7/32 since the new tires have more miles on them. Is this something I should worry about...is the slight diameter difference going to effect anything or should I just patch the tire. Dealer is suggesting a whole new set....again.