Can anyone help me with this? I spoke to a Tirerack rep yesterday cause I was looking to pick us some wheels and tires. I had asked him if I could go with a 245/45/17 instead of a 255/40/17? For better traction in the snow. He was really arrogant and basically told me if I did this, it would void my Warranty since it could cause tranny issues and engine issues because it's a different width of a tire and the 2002 A6 4.2 is only calibrated for the 255/40/17. Does anyone know what he was talking about?
thanks

 

I must say I am surprised. The folks at TireRack are usually pretty good. You, however, got an idiot. No problems with that size and his comments about the warranty are BS. Call them back and ask for Gary if you want a 2nd opion. He's the resident Audi expert there.

 

He was correct in saying the car is calibrated for the size tire on the vehicle. However the most important dimesion is the rolling radius, otherwise know as circumference. Im too lazy to plug those sizes into a tire calculator but i think they have slightly different circumferences. Which will result in your speedometer and odometer reading slighltly off. It could also cause some eradic abs and esp function but i think these tires are close enough that it wont be an issue. As long as you go with the same size tires on all four corners you shouldnt have any warranty issues. As for the slightly skinneir tire offering better snow traction, i dont think the difference would be noticable between the two tire. I would recommend a set of snow tires in the factory dimensions.