Okay so Audi says 4/32" which means a diameter difference of 8/32". So my question still remains, if new tires of different brands are .1" different why is that not recommended when in normal wear Audi says up to .25" is okay?
The reason for my persistence is that I just bought my S4 and it has almost new tires on it but the fronts and rears are different brands. I had not expected to need to buy new tires right away but of course do not want to damage the car.
I have a follow-on question. Last time I visited the dealer, the dealer stated that I needed 3 new tires since 1 was at 9/32" and the other three were at 6/32". From what was posted here earlier, it seems like all four tires are within the acceptable range from Audi AND within 4/32" of each other.
The reason for buying three was given due to tread depth. There were no uneven wear patterns at all.
So was this merely an attempt for the dealership to sell tires (at their markup) or do y'all tend to replace them when they reach 6/32"?
I'm trying to do right by this A6 but am just also trying not to be snookered.
Thanks Reggie, I recognize that handling will be affected and that either end of the car may come loose before the other unexpectedly. As long as I will not ruin the center diff or other parts I am okay with this. Here in New Zealand most of the tyres are Chinese or Asian imports of lesser quality than tyres I would buy in the US and are not major brands (unless you spend a LOT of money for the Pirelli, Bridgestone, etc).
So both pairs of my tyres are strange name imports and both sets are probably equally as bad. The handling so far has at least been balanced with no loose end showing up in normal wet and dry driving conditions and a few spirited moments on the nice curvy roads we have here. Until I replace all four tyres with something good I will just be more careful and not drive at 10/10ths.
Yes, they spell tyres like that here, and no, the toilets do not flush backwards.