I had a flat tire on my A6 Quattro, and I'm temporarily running on a spare tire. Does anyone know what an acceptable limit for difference in tire diameter would be for the Quattro. Taking some measurements of my tires, three tires have an average of .198" remaining tread, while the spare has .267". I assume this will mean that my rear differential will be constantly turning at a slow rate. The flat tire is non-reparable, so I hate to buy 4 new tires.

On the new tire subject, anyone got any experience with the Yokohama Avid V4S tires or the Continental ContiExtremeContact tires? I'm looking for wet/dry performance, but some winters we get a few days of snow. I would like to run only one set of tires. Is it worth paying the extra $s for some Michelin Energy MXM4 or Bridgestone Potenza S03 tires?

I don't think you need to worry about such a small difference in tire diameter. The differential is designed to handle this sort of thing, i.e. limited slip. Even the left vs. right will not be an issue. (e.g. The side with the larger tire will turn faster then the other side.. same as when you turn a corner, the inner wheel always spins slower.)

On some four wheel drive vehicles, usually more the 4WD (Four Wheel Drive) variety as opposed to AWD (All Wheel Drive), the front differential runs a very slightly higher rate than the rear diff. This creates a more stable drive as the front is all ways 'pulling' the rear of the car. (Front Wheel Biased)

As far as the tires mentioned, I have no experience with them. Good tire place you trust might help, or a review on the internet. I am running Nexen 3000's. They rate around 3-4 /5 in most categories, so a good all around tire for ride, noise and performance. My tire guy told me they are made by Michelin, not sure if he is right, but he knows his stuff.

I will use the stock rims in the fall and mount up snows. I live in Canada, so its a good idea. While the quattro may give great handling and acceleration, I still want the snows for braking.

Page from an A4 manual.





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