Tire question- can I replace just two tires on my quattro?
 

I have a 06 a6 quattro 3.2 that i bought 1 year ago. When I bought it I was told that the front tires were recently changed, but rear ones would need to be changed soon. I took the car in for service today and they told me That I need to change the rears cause they are bald. Dealer quoted me for two tires, but I asked another shop in town and they said cause its awd I need to replace all 4 otherwise I run the risk of messing up the diff. Is this true? The tires are the Pirelli 245/45/17

The Quattro system is rather sensitive when it comes to tires. You need to use the same model and size tire all the way around. In addition, the circumference of the tires need to be within 3% of each other. As a result, you can keep the older tires if they have very little wear, perhaps 10,000 miles or less. If the older tires have more than 10,000 miles you will need to replace all four.

If that was an Audi dealer I would take my business elsewhere for service. They should never have sold a Quattro with only two replaced tires in the first place. Go with the other installer and buy 4 new tires.

You'll find varying opinions regarding quattro sensitivity to this situation; I don't think "always change all 4 or doom your car" rule I've heard from tire shops should be taken as law.

A front-alignment issue had me in a similar situation recently, in talking to my SA he said that as long as I kept the similarly-worn tires on the same axle - but otherwise had matching tires (eg make/type) on the car - it would be fine.

My overall tire set had only 11k miles on it, and rears not only still have tons of thread, but have almost identical amounts left.

But I will admit that I haven't done anything about it yet ;) - instead of buying two summer tires in September, I decided to do an early switch to my winter set...I've aggressively postponed action until the spring.

Hope this helps, at least a bit...

all tires must be within 4/32" of each other.ive replaced single tires.

I've also heard 3% tolerance between all four tires. In addition, I have been told that it's the center differential, not axel differentials, that could wear out prematurely. Hence, keeping similarly worn tires on the same axel won't help you. This is one of the reasons why Audi provides Quattro vehicles with a full size spare tire.

Something tells me that you didn't purchase your car CPO from a dealer. If you did, I'd demand that they replace the tires. They should of never have sold you a car with two different sets of tread wear.

If your spare has a new tire, and you want to keep the same brand, get three new tires and use your best tread wheel as a new spare. At least you will save some $$.

Thanks everyone, after weighing the options and price difference, I think its best to replace all 4's, and just sell the two OEM pirellis that are fairly new.

You made the right decision.