OOOOya

I was changing oil on the S6 this morning when I glanced over and saw this. I've only had this car for 3 months and so far have put a little over 3000 miles on it. The first 1700 were in less than 2 weeks to get it home, where I immediately rotated the tires front to rear.

There is a distinct groove worn into the tread and in places (the worst pictured) has gone through to the inner structure. The groove is not consistent around the tire - there are sections where I can still faintly make out the root of the tread pattern.

This is only happening on the left side. I got ALL records with the car and there was an alignment done ~12,000 miles (one year) before I got it.

Everything about this car is tight and I have no reason to even think about questioning the previous owner (a long time AW member).

I know this tire did not look like this when I rotated them, and I had vaguely remembered something odd when I did the rotation - sure enough today I took a look at the drivers rear and it has the same groove worn into it - not nearly as bad though.

Everything about the car is stock - suspension, brakes, wheels, tires are stock size 255/40-17 Kumho Ecsta inflated to 36psi (yes, I checked)

After a bit of thinking, I can only guess that during spirited driving (who can resist?) the tire is squirming enough in right hand turns that the groove is being machined into the tire by the prominate boss sticking out of the alu. upright just under the upper control arms. However, there is no obvious shiny, rubber polished look to support my theory. With the car flat and the suspension settled, the area between that boss and the tire has the least clearance(less than 15mm). The next likely candidate for contact would be the tie rod end (which were changed right before the alignment with Lemfoerder "S4 style" 4D0-422-821-A)

The tires do not exhibit any other abnormal wear at all.

Any AW BTDT?

Get wheel spacers, or grind the offending boss off & problem solved?

<img src="http://pictureposter.audiworld.com/74843/img_5542.jpg">

<img src="http://pictureposter.audiworld.com/74843/img_5540.jpg">

<img src="http://pictureposter.audiworld.com/74843/img_5544.jpg">

BernieBenz

Is that a crack in the Al retaining the front CA ball joint rod? Excessive negative camber would bring the tire closer to the vertical upright. You need an alignment check. Any tell tail wheel bearing noise? A sloppy, failing wheel bearing could also be a cause.

4Driver4

Unpossible.

TXurS6

BTDT

OOOOya

...no suspension slop. I pushed &amp; pulled in every direction.

I agree that there appears to be no contact, but if the camber or toe was out, the tread would be scrubbed away in a wider, more flat area, and it would be uniform all the way around the tire. The worn groove just doesn't look at all like road wear.

OOOOya

I don't disagree, &amp; I briefly considered the same, but why only the left front?

Kris Hansen

or at least, many do.. Mine does. I've seen others that do too.

TXurS6

The only other explanations are that it's out of alignment (hit something since the last alignment?) or a defective tire. The wear looks like classic underinflation although I would expect to see the same wear on both sides of the tire.

OOOOya

the regional trusted source for an alignment check &amp; to swap the tire.

TXurS6

Any slight misalignment or worn control arms will make it worse.