Reedo1

RoMan709

I would replace the one tire, use the unused (hopefully) spare tire and move both good tires to the rear and the one good used tire as your spare. This way you maintain the traction balance on each axle and get use out of the unused or slightly worn spare tire in the trunk. Also in wet weather it will be tougher for the back end to turn out or skid in a curve...even with all wheel drive. JMHO

Doc@tirerack

Assuming we have the identical tire in stock, I can shave one down to match your (remaining) tread depth on the damaged tire for $ 30

Give us a call with the tire size / brand / model and an accurate tread depth !

andrewmr

Yes.... and no....

the problem is the car needs tires with uniform diameters. If the other three have significant wear and you put a new tire on, the diameters could be off far enough to create issues. Issues that range from traction control to wear on the quattro system.

As Doc said, the solution is to replace one tire and have it shaved to the diameter of the others.

I would ask with 42 thousand miles on the car, how much tread is left? I'm assuming they are original tires.....