Wondering what anyones tire knowledge says about this. My wifes C300 goes through rear tires about half as fast as the fronts. So I ordered two new rear tires and took them to Costco to have them mounted up.

I was told that they couldnt do it because the front tires tread were more than 2/32nds worn over the new rears. Basically they are saying that if the new tread is more than 2/32nds than the old tires that it will mess the cars transmission up.

Ok, I could go either way on this but am wondering what anyones experiences with just replacing rear tires on an all wheel drive car. Are the tire companies just trying to make a buck or does it really matter?

I suppose my main reason for asking is: even if you put all new tires on the car at the same time. By the time you hit 30k miles, because of the way Mercedes engineered their system, the rear tires are 4/32nds less tread than the front. At this point I am probably 2/32nds different at 15k miles!