TTilley

We've had our Nimbus Grey 225 TTR with Mocasin Red baseball-stitched leather for one week and we love it! We ordered in September, 1999.

Question: How wide of a tire will the 225 TTR accomodate on its stock 17" 5-spoke rims? When I picked up the car, I noticed an A6 in the showroom with what looked like the same 17" 5-spoke rims as on my TTR. My dealer said they were the same. My tire width is 225. The tire width on the showroom A6 which I believe had the same rims was 255. Could I run 255s on my TTR? Would I have to run smaller tires in front. Where can I find out what tire sizes are compatible with my car and its stock wheels?

Thanks for your help.<ul><li><a href="http://pictureposter.audiworld.com/AudiWorldPics/2000/office_lot2.jpg">http://pictureposter.audiworld.com/AudiWorldPics/2000/office_lot2.jpg</a</li></ul>

TTinGables

1) Maintain the sidewall height of your present tires, or as close as possible, or else your speedometer will be off, and braking distances will change. The stock tires are 225/45, meaning a sidewall height of 3.986". If you put on a set of 255/40, those would have sidewall heights of 4.015", so they are a good substitute. If you went with 255/35, those would be 3.513", which would lower your ride height by almost 1/2 an inch, and are almost 1" smaller in diameter, so your speedo would be off.255/45 would be too tall.

2) Aerodynamics (and as a result, mileage) suffer the fatter your tires get, and they have a tendency to follow ruts in the road more. At speed, you may notice more wandering.

3) Fitting in the front wheelwell so you can make full turns without making hideous noises and shredding tires and bodywork.

4) Acceleration is slower. Your car has to spread out it's ability to overcome inertia over a wider area, and there is less weight over the same area (tire footprint).

5) Another practical limitation is the width of the wheel. When the tire is much wider than the wheel, the sidewalls have to bend in slightly on both sides of the wheel. This reduces the stiffness of the sidewall, and results in poorer handling, and if too exaggerated, looks really stupid too (like dragster gumballs).

That said, the quickest, most profound single change you can ever make to your handling is wider tires. More of an effect than any anti-roll bar, or shock/strut combination, taken by themselves.

Good luck!

TTilley

Thanks for the info, TTinGables. I'm learning a lot. Also, I realize now I should have posted my question on the Wheel & Tire forum.

Thanks again.