i recently had a shop tell me that i need to replace my front tires because their circumference was significantly less than the rears, and that could screw up my differential. now i know that the fronts will wear more but does anyone know what the actual maximum difference should be...or even heard of this? thanks

 

If you have quattro this can screw it up. Based on the fact that if your circumference is smaller the wheel must spin faster to go the same speed as a wheel with larger circumference. That being said, your quattro senses different wheel speeds and it Mooks up....

Thats the bottom line. I dont know what the maximum difference is though.... 1/4" ?

 

BS!!! There is not enough tread on a tire to make a difference. No one can concince me that if you have new tires in the rear and bald tires in the front that it'll matter. There is more of a difference caused by the weight biass in our cars than you'd ever tell from treadwear or if a tire has less pressure than another. He justs wants your money.

 

This is true, there is not that much tread to screw your differential.

But tire circumference does matter.

 

thanks, that's good to know seeing as i didn't wanna half to spend another $300 or so on 2 new tires...

 

As long as the tires have close diameters, same tread depth, left and right you're OK. You should use the same model and size tire all around. Front to rear wear is not important.