Tire circumference and the center Diff
 

I know that all 4 tires need to be basically the same circumference to avoid damaging the center diff. My question is how much difference is too much? I want to play around with staggering tire size front to rear, but the sizes I have picked out are 2/10ths of an inch different front to rear. Is that enough to screw up the diff? This setup would be used for track days and auto-x only.

I would not recommend it. From my own personal experiance, if you forget to rotate your tires, the difference in diameter is enough to stress the center diff.

The tires won't get rotated, they will be dedicated fronts and dedicated rears with different section widths. The fronts are 24.8" and the rears are 24.6".

Greg-
You should be OK. I know of a few DSMers doing this not only at the track, but daily driving as well. I don't recall the exact size differences at the moment, but your .2" seems reasonable. <Insert disclaimer here.> :)

Our Tech Center has as great page on matching tires on 4WD vehicles. Heres a part from that page that might answer your question:

"As an example of different tire diameters resulting from tires worn to different tread depths, we'll compare two 225/45R17-sized tires, a new tire with its original tread depth of 10/32-inch and a second tire worn to 8/32-inch of remaining tread depth. The new 225/45R17-sized tire has a calculated diameter of 24.97", a circumference of 78.44" and will roll 835 times each mile. The same tire worn to 8/32-inch of remaining tread depth is calculated to be 1/8" shorter with a diameter of 24.84", have a circumference of 78.04" and will roll 839 times per mile. While the difference of 1/8" in overall diameter doesn't seem excessive, the resulting 4 revolutions per mile difference can place a continuous strain on the tires and vehicle's driveline. Obviously, the greater the difference in the tires' circumferences, the greater the resulting strain."

Awesome info Neal, thanks!

no prob :thumbup:

How long does shaving add to the delivery time of an in-stock v700?

On average it adds about a day to delivery time.

Placing order now... {thumbup}