I have a 2000 Audi A6 4.2 and just had a new set of tires installed — but purchased the same Continental tires. However, two days after the new tires were installed, I started getting a shimmy when I brake. Would replacing the tires impact the rotors and lead to this shimmy or is it just a coincidence?
The only impact that could possibly bring on a warped rotor is if the wheel studs were over torqued. In order to prove it you could go back to the tire shop and ask them politely to grab a torque wrench and set it to 85ftlbs (i believe this is roughly the spec for the Audi wheels). Once he grabbed the tool and placed it on the wheel stud and attempted to tighten the stud it would click. A bit more effort and the lug should turn. If the lug is impossible to move unless you put some real effort into it after the "click" from the torque wrench is heard. Then this would indicate that the wheel is over torqued.
Mechanics, especially flat rate mechanics, tend to rush drops since their pay is directly related to amount of work that they get out the door.
If you were to do this and show the wheel studs were in fact over torqued. You could bring Audi Documentation to them stating that if wheels are over tightened it will cause the rotors to warp.
The only other cause could be that the wheel was left loose. But you would have suspension type noises in the front end with this and a rather loose feel to the steering wheel.