I bought a 2004 A-6, 2.7T, S-Line in May. On my drive home (40 miles) noticed a tire balancing problem. Returned to the dealer and they determined that the original Pirelli's were defective. Installed new Pirelli's a week later. Then drove to St. Louis from NC and had the same problem. At my request new Michelin's were installed. Seemed OK except for a slight wobble at 45-50 mph that passed quickly. Then it got worse. Took the car to a local Michelin dealer (damn the cost) and they determined that two of the tires were out of round. Put them on the rear but still feel the vibration. Told the dealer and they immediately ordered two new tires to be installed this week. The dealer (Deal MotorCars of Asheville, NC) has been very helpful. Have been using them without complaint for 9 years.

Question. Is it really possible to have so many defective tires??? Could it be the wheels? The dealer tells me the wheels are OK, but now I'm wondering.

 

i do not think it is tire trouble. once maybe.
does anything happen while breaking, turning, accellorateing?
any niose?
are the rims scraped etc, from a curb, pot hole?

i would start to look at rotors, drive train etc.

 

it could easily be tire trouble. try a different brand, perhaps high-end performance. also drive another audi - same specs - see if it just feels a certain way. just a thought.