Tire sizing tolerance

[X53Jay4.8is]

Originally Posted by jdstrickland

I do not know the answer to the question, but the issue is the difference from front to rear in the tires sizes he has selected.

The car does not care what tires are used, it only cares that they are all the same circumference. Any comments of a square fitment does not apply to the question asked.

The specific issue here is what effects the t-case will suffer when the front and rear are going different distances for long periods of time. The front and rear will always go different distances when going around a corner, but the difference is a transient conditin that will end as soon as the car is going in a straight line again. The difference in tire speeds over a long distance is the question, how different can the speeds be without killing the t-case?

The OP has already calculated the rotations per mile of his selected sizes, and he arrived at a difference of 17 rotations between front and rear. The differentials deal with the different speed/diameter/circumference from side to side, the t-case handles the differences from front to rear. He's asking about the potential harm to the t-case. On a square fitment, there is no harm. He's got a staggered fitment.

Simply put if there is a diameter difference of wheel and tire from front to rear then problems most definitely will occur. Having a staggered wheel fitment is not a problem providing the diameter is the same between front to rear. Thats the way many of them came from the factory (all IS models).