Nebuul

I am looking to switch from 20" wheels to 19" wheels. I will probably end up going with a 19x9 setup similar to default OEM wheel size. But my question is this, because I'm not real knowledgeable about tire fitment:

Why does Audi use 245mm wheels for their 19" and 255mm for their 20" wheels? I would assume they'd use the same-width wheel for both since the wheels are 19x9 and 20x9 respectively. What effects will it have on my handling, stability, and ride if I use 255/35 instead of 245/35 when I switch to a 19" wheel?

https://www.audiusa.com/models/audi-...r.MRADCP7.html
https://www.audiusa.com/models/audi-...r.MRADCN7.html

Also, please note that I plan on buying lighter-weight wheels than the OEM (so long as they have appropriate load ratings), but I need to find out this information, too.

Thank you for any information!

Huey52

First off, I applaud your decision to go with 19". I feel it's the sweet spot in performance and aesthetics on this vehicle.

btw: You'll note the OEM 20" wheels use 255x30 and not 255x35 so as to achieve a near parity of 26" diameter as it relates to maintaining similar outputs for speedometer/odometer, ABS-based TPMS etc.

Any of the online tire calculators will show you the differences in going with non-OEM profiles. The upside to the larger contact patch of the 255x35 is of course a little enhanced traction and some meatier aesthetics. The downside is a little increased "railroad tracking" (a bit less agility). Also the non-OEM profile will decrease rev's per mile by 9 which will somewhat effect speedometer readout vs. reality.

For several seasons I used 245x40 18" winter rims/tires simply because I had them available as hand me down from prior Audi's. More comfortable and pothole resistant (but not always) given taller sidewall but again less agile.

All design is compromise and there are pro's and con's to any change from OEM.

Nebuul

Thanks for the info. I was ignorant even to the existence of tire calculators! I was thinking that width was width and sidewall height was height, so I just thought a 255/35 would have a 35mm sidewall. It didn't occur to me about the wider tire contributing additional circumference to the outer diameter of the tire.

I think I'll stick to 245/35 then when I go back to 19" wheels.

Do you happen to know the tire load requirements for the tt rs coupe? I did not see the desired info in the door jam (I have not yet had a chance to see if it's in my manual)

Thank you!

Huey52

Go with the Owner's Manual chart, as the door and/or fuel door placard tends to list the maximum vehicle loading inflations which can be misleading.

https://cimg2.ibsrv.net/gimg/www.aud...696af15b5a.jpg