Do I really need to replace all 4 tires at one time?
 

I blew out one of my Nokian WR snow tires in a pothole. Problem is they don't make them anymore. I keep seeing you need to replace all four tires when you have all wheel drive. I believe just the front two may be OK. Here is my reasoning: While having different tires/wear levels side to side might present some issues given the nature of the quattro system, front vs back should not, precisely because of the vaunted Torsen system, which mechanically adjusts continuously for difference in traction, etc. Am I crazy or will I ruin the transmission if I put Nokian WR-G2's on the front?

Any opinions?

Having driven with different sized tires in the past I would say no, a minute difference due to new thread will not affect the system.

Depending on how worn the opposite side is, you will probably be OK with two, at the most. Put both new ones on the same "axle", of course. If the tire 'on the other side' still has a lot of tread. maybe you're OK with just the one new.

BUT....

I would be a little cautious about running tires with two different tread patterns on the same "axle" (front or rear), since their traction performance might be different enough give you handling problems.

$.02
 

I used to have a Subaru Legacy Outback Wagon with manual transmission and awd. It had a torsen center diff, similar to the Audi design. This was a hotly discussed matter on the Subaru boards. People who ran different sized tires front and rear pointed to a condition known as "torque binding" where the car would buck and jump while going around tight corners, esp in parking lots, etc. The theory was that constant work by the center differential would cause stress and overheating, which in turn led to torque binding.

There were also those who had run 200k miles, never paid attention to matching tires, and never had a probleem.

I never had the torque binding condition with my Subaru, but I always ran tires that matched. When I bought an Audi, I looked into the mfr recomendation for tire size, and Audi is more liberal when allowing a different sized tire than Subaru. Maybe Audi's system is more forgiving?

Be sure to explore all options. Sometimes you can find a discontinued tire online, tirerack.com etc. Be sure the tire is the same size, and if you are really worried, you can have a new tire shaved to match the existing.

Good luck.
John

I think two are fine. But here are the issues:

1) you need - both front to back and side to side - similar (not exact, close) rolling circumferences or else there will be constant motion in the diff. It matters not if its open or Torsen - motion is motion.

2) Similarly, both ABS and ESP (stability) operate based on relative rotational speed of the various hubs/axles. If the rolling circumferences are different enough, ABS or ESP could be confused.

3) On any car, FWD, RWD or AWD, if you have worn tires at one end and good at the other, you will either make it understeer more or oversteer more. Typically, people say "put the good ones on the front because they steerr". True. but that also means the rear end can snap out mroe easily - and most people panic when that happens. You choose.

Yes, i have even replaced ONE tire on a quattro and all was fine. The others were only worn about 3/32"

G

Also check on eBay to see what's available. You'd be amazed at the odd-ball tires and stuff that people want to sell.

Very good point here. Also check your local used tires places. They usually have thousands of misc tires lying around, you might just find the right tire for yourself.

thats what i did to pass the time till i needed 4 new tires :)

tire size doesn't matter one little bit.

Its the difference between tires that matters.

I run all 4 tires + 2.8%, which is a lot. But the sensors and the differentials don't know the difference. All they know is how fast the axle's rotate.

G

To be clear - not changing tire size just tire model
 

Still going with 235/45-17's just going with the latest generation Nokian's since the ones I have are not made anymore