David P

Good day - I have a tire question and thought I would get some input. I have a 2011 S4 with 17,450 miles. I have a tire problem on the rear tire that is not repairable. I ordered two replacement tires for the rear and planning the leave the front tires alone. My question is this: with the quattro system will there be any performance/drivetrain issues with replacing just the rear tires, or should I replace all four. They are rather pricey, so it's worth the investigation.
Thank you for any input you may have regarding this problem.

motorsport_mike

Don't do it!

The Quattro system will immediately stop functioning, your warranty will be voided (TD1), and the wheels may fall off if you exceed 55 mph.

I would advise replacing all five tires to avoid any performance/drivetrain issues.

DrGP

The spare is a donut! So he only needs 4(just continuing your line of thought) Nod,Nod, Wink, Wink. Just buy 1 tire from Tire Rack. Have them shave the tread to match that of your current tires and be done with it. It will save you money and no worries about different diameter tires.

snagitseven

Probably not the type of advice that a newcomer that came here for help was hoping for.

The tire shave is a good inexpensive solution assuming the other three tires have enough tread life remaining. If not, the OP will be tossing the shaved one along with the other three pretty quickly.

As published in their vehicle owner's manual, Audi states "rolling radius of all 4 tires must remain the same" or within 4/32-inch of each other in remaining tread depth. If that's the case, no shaving of the new tire would be necessary.

eric strauss

... the question is the degree to which the fronts are worn. 18K is pretty good for performance rubber. We get about 10K from our S4/S5/RS5. If you rotate the tires, you can better distribute the wear. Audi's are nose heavy and understeer - they are brutal on front tires. Also, when you replace all four, you can negotiate for the best tire deal. I recently did all four on both cars and there were huge differences in the discount, depending on brand. I put Continental Sport Contact Extreme on the S4, but went with a harder compound then the original. On the S5, I put Michelin Super Sports as I like the dry weather handling and the progressive way the tires give up traction.

Happy Motoring

Eric'

David P

Thank you for the helpful comments, what my question should have asked was if you have a (one) tire of a different diameter on long term - either front or back - would it effect either the handling or long term wear on the Haldex differential. I replaced both rear tires with the Dunlops, I will switch to Michelin's in the future. Thank you again for the thoughts.

snagitseven

My previous post would still apply. The variance shouldn't be more than 4/10th of an inch difference between all four wheels. If the difference exceeds that, Audi states that driving for an extended length of time could cause damage to the Quattro system.