bac2h

PSI are you running? Bought a set of used Stasis with new Falken's on them. I have no idea what PSI to run so I guessed at 40 but would love some input from someone with better info than my guess.

Thanks in advance.

Resoom

Am running 38/39. Did run 40 just trying something different after B8 and H&R install.

bac2h

Thanks for the info...might play around a little with them.

riceboy22

For wider tires, you should be running lower pressures than you would on an equivalent narrower tire. I started out running my 275/40R20 tires at 38/38 psi and ultimately dropped it to 36/36 psi. If you run the same pressure as your stock 255 tires, you're going to get a harsher ride and you're not taking advantage of the potentially larger contact patch.

MP4.2+6.0

Here's one unusual hint, since we share some overlapping car history.

So, your SQ is in the same general weight area as the prior D3. Maybe a little more for SQ actually. If you had sport package on a later D3 you were running 275/35-20s on a 9 inch wheel just like in your signature picture. What was your long term experience there? I settled on about 39 pounds there all around, even with heavier and more powerful W12 motor. I would back off a few pounds, both given the higher 40's sidewall and the lack of air ride on Q5 class to smooth things out at the margin. High center of gravity on SQ limits way before tire stick anyway. I'm running 275/40-20 on D4 S8 now FWIW and have moved to lower end of range per manual to smooth it out a bit more. Factory 21's were not the hot set up there--both unsprung weight and slightly unsorted overall feel. 36front/32 rear is the part load setting for closest 20 factory size there (a 265/40 for D4 S8 spec) and 39/38 for full load. Not enough miles yet to assess evenness of tire wear. On D3 exact pressure seemed important for even wear across tread in the 275/35's, especially in back that would tend to wear centers if pressure was a little high.

Back on my Q5 Hybrid with 20's at factory 255/45 summers, ride is already a bit rough. Probably similar weight to an SQ or even a bit more. Lack of air ride or even shock tuning shows on that set up. D3 or 4 are much smoother even with lower profiles and more width. Likewise backed off tire pressures some on the Q5 but within owners manual part load range for 20 fitment. Q5 factory wheels are also cast weight pigs as they go, while I have been using lighter factory forged choices on the A8/S8. The wheels in your D3 picture are the Fuchs forged ones--lightest factory 20's sold for Audis other than (narrower front) R8, and put many larger Audi cast wheels to shame, whatever that body or any other. Affects both ride and performance at the margin with higher unsprung rotating mass weight.

andrios

Running 275/40/20 Conti DW

36psi feels the best so far.

After install discount tire had them set way to high, I thought something was wrong. Took some air out and now they feel real good.

bac2h

I will back them down to 36 and see how it feels...Not sure what the weight of my Stasis wheels are. They are 10 inch wide and think they are cast and not forged? I think Stasis used to stamp forged somewhere but am not sure of that. Anyway...Thanks to all for the input.

Yoshimura

You should use Load Inflation Tables.

Using the table for your original tires, find the load at the recommended pressure. Then, using the table for your new tires, find the pressure required for this load.

Check this document for more information.

Barraged

That is one helluva document!!