heymoe

I was getting ready to same the same thing. The fronts have more weight over then, have to deal with steering the car and receive more wear when braking.

Nikon1

Hematose

If the back tires let go in a turn, then they are the ones doing the steering. If you are going straight, it doesn't matter as much. It's a question of picking understeer vs. oversteer. Generally the latter is thought to be more dangerous.

MH62

I agree, traction in rear is more important. Just take it to the extreme, a car with great traction in front and poor traction in back will lose out in a race to a car with poor traction in front and great traction in back. I've raced karts on wet tracks with slicks up front and rain tires in the back but never the opposite, it would immediately spin out.

superswiss

+1... as posted above, the main reason for putting the better tires on the rear is to make them less likely to hydroplane and cause a massive spinout. If the front tires hydroplane, the car keeps going straight and simply reducing the speed will eventually make them regain traction. Much easier to control than a spinout. On cars with the sport differential, the rear tires can steer the car to some extent if the front tires hydroplane. If the system senses that the car is not following the intended direction it will send more torque to the outer wheel to induce a steering moment, and ESP will apply the inner rear brakes to further coax the car into the intended direction. This all won't work if the rear tires don't have any traction and you are spinning out. In general you want the rear tires to lose traction last, unless you are deliberately trying to power slide and drift in a controlled environment.

future S4

This is correct - you need to check this requirement. Should be in your owners manual. I went thru this recently with my wife's TT which had one bad tire due to a road hazard. learned I needed to replace the whole set, but not recalling exactly how much variance is allowed. Check it out. If you're OK on the tread depth I agree with others that the new tires should go on the rear.

belzebutt

I would counter that braking performance is THE most important. Being unable to stop in wet conditions seems like a more likely problem than spinning the car due to slightly lower traction in the back. Most accidents happen because you were unable to stop in time.

JD15

Yes, I'm surprised no one mentioned this. I think the OP is within spec at 8-9/32, but he should verify.

jhstl

The tires were not worn very much when they blew, so the difference is only 1 or 2/32nds of tread. I would think as long as I put both new tires on the same axle I should be good to go.

From tirerack: AudiAs published in their vehicle owner's manual, "rolling radius of all 4 tires must remain the same" or within 4/32-inch of each other in remaining tread depth.

superswiss

Yes, it is, but the misconception is that more tread improves braking. It actually worsens it. Pure tire grip increases as the tire wears, believe it or not. That's why race cars use slicks. The tire tread reduces the amount of material on the ground. The only reason street tires have tread is to dispel water and trap snow. If the tread is too low and the car too fast so that not enough water can be dispelled, the tire starts floating on the water and traction is lost. Once you hydroplane, the worst you can do is to step on the brakes, so the ability to brake is the least of your worries once hydroplaning. So the most important thing is to make sure your rear tires do not hydroplane. Because if they do, you gonna spin out most likely. Hydroplaning occurs if the car is speeding up or already driving faster than the tires can get rid of the water, not when braking, and slowing down actually reduces the risk of hydroplaning because the tires have more time to get rid of the water.