B7Quattro Pete

A friend told me that using different brand tires on a quattro can be a problem. For example, I just wanted to buy two new fronts, Fulken 115's, and leave the good Pirelli P7000's on the rear. I don't see an issue. Am I missing something by installing very similar type tires though differnt brands? Thanks.

A6qwDenver

...different manufacterers have slightly different definitions of what a mm is . As long as they are substantially identical in design and size, you should be ok.

QCRAZY

...tires on any car with a *tuned* suspension. It can create quirky handling issues.

A6qwDenver

..and more on the sizing issue: hen you have different sized tires on a Quattro (even slightly) or any 4 wheel drive vehicle, it's almost like running different sized tires on the right side and left side of a 2wd vehicle. The radius of the tires is different, therefore the rotating circumfrence is different...i.e., you end up with different distances for the tire to travel one exact rotation. This inherently causes different torques on either side of the driveline, causing irregular wear on the driveline parts which = a very long weekend on your back looking at driveshaft parts.. doh!!

Malcolm100CSq

I agree - not a good idea, may affect handling & circumference HAS to be same

B7Quattro Pete

Thanks.

Both tires have very similar tread patterns (uni. also) and perhaps the Fulken is a mm wider than the P7000's (both are 235/40-17's)? I didn't see any bigger issue than having pretty worn tires on the back and new ones on the front and all the same tire brand and spec.

Ultimately I want to get away from the Pirellis but have many miles left on the rears and prefer not to dish out another $300.

samm

You can not use different size/brand tires from side to side on a Quattro because of the Torsen Differentials. You can use different size (same size different brand) front to rear. This is talked about in the owners manual.

Your friend is thinking of a car like a Subaru that uses a Viscous center differential, in which case you can not use different size/brand tires front to rear.

And of course as the others mentioned it is always best to use 4 of the same tires. If you rotate your tires regularly you won't end up with two worn out tires and two good ones.

QCRAZY

Side to side has NO bearing on the Torsen differential. (There's only one in these cars) Front to back would make more since but side to side does not.

If the owners manual does state what you say it would not be becasue of the Torsen diff.

Anyway, it's just a bad idea. Don't be so cheap :-)