ok to replace just 2 tires on quattro?

[avantnoob]

Lost a left rear tire to nail in sidewall on an A4 avant 1.8t quattro, now at 15K miles. Much to my surprise, since I bought this certified from dealer at 10K miles, when I took out the spare it was undriveable with massive sidewall damage from being driven flat.

So, my dealer agreed to replace the spare with a new tire at no charge (since they should have done so when inspecting / certifying the car a few months ago), and I'm buying a 2d new tire to replace the old left rear tire with damaged sidewall. I asked dealer to put the two new tires on front; rotate the old tires from front back to rear; and use the old right rear tire for the spare.

Questions:

OK to put on just 2 new tires, or should I be replacing all 4 at same time?

Was it correct to assume the 2 new tires should be on the front, not the rear?

For what it's worth, the tires are Michelin Pilot HX - MXM4. 16" wheels.

[Oscar@tirerack]

Two vs Four. That will depend on the tread depth of the two remaining tires. And those two tires should be moved to the front axle. And the new ones mounted in the rear until the 1st rotation.

[avantnoob]

thanks oscar. how important is it to have the new tires on rear instead of front?

i had thought from replacing tires on front wheel drive cars the new ones should go on front; when i asked dealer to do this instead of on rear, they agreed and put the new ones on front (and waived charged for rotating tires).

i picked it up this a.m. with the two new ones on front and it seemed to drive OK both on freeway and surface streets, rainy day. not pushing it too hard but i don't usually.

so, is this so important that i should have my local shop rotate? is this a safety risk?

[SF944]

I think everyone (myself included) has assumed FOREVER that new tires should go on the front axle. Last month MotorTrend magazine did a piece on dispelling that myth.
Aparently, Michelin (I think) did some testing with full-depth and half-depth tires run on front vs. rear, and ran the car over a glass panel to take pics from beneath. They did an extensive write up on understeer vs. oversteer generated due to either setup -- I won't go into the specifics here, but for MOST DRIVERS, it seems the SAFER setup is to put the new ones in back.
Now, if you tend to like the car to rotate and you have the skill to bring it back, you may prefer the other setup.
The article stresses that if the older set of tires doesn't have a safe amount of tread left, then they ALL should be replaced. Good advice.

[Oscar@tirerack]

Originally posted by avantnoob
thanks oscar. how important is it to have the new tires on rear instead of front?

i had thought from replacing tires on front wheel drive cars the new ones should go on front; when i asked dealer to do this instead of on rear, they agreed and put the new ones on front (and waived charged for rotating tires).

i picked it up this a.m. with the two new ones on front and it seemed to drive OK both on freeway and surface streets, rainy day. not pushing it too hard but i don't usually.

so, is this so important that i should have my local shop rotate? is this a safety risk?

The Tire Rack always states to put the new set of tires into service on the rear axle till the next tire rotation is done.

[DRA4]

You have quattro, so you have to replace all 4 of them, or a least shave the new ones to the level of the old ones.

[Diesel'S4]

new tires on the rear, but i would replace all 4 without even thinking about it...