Imdomina

We see this on RS5s and I think a few other models. Guessing the reason is the slight additional bulge from a 9" rim helps absorb a little impact that the skinny 30 series sidewall otherwise doesn't, but that is a guess.

Considering upgrading from S5 stock 19" cavos to a 20" wheel. Concerned with road imperfections and the skinnier sidewall. It's typically recommended to go with a 20 X 10 rim for 275/30/20s. Wondering if a skinnier 9" rim would help.

ShiftyWolf

I read a lot about recommending a 10" wheel for a 275 tire but I've always thought it looked great on the stock 9".

Michelin PS4S on the stock 20" wheel

There is a little bulge but not much, and I far prefer this over the stretched tire look I saw on some of the BO optioned S5s when I was purchasing.

Just my opinion

superswiss

The rim width range for a 275 is 9-10". 9" gives you a square setup and 10" provides a slight stretch. I think it has to do with practical reasons. Audis are more about utility than performance and keeping the tire square allows things like snow chains in the winter. Other performance brands like AMG for example put the tires on the widest possible rim, which gives it a slight stretch for better sidewall strength and reduces the likelihood of the tire rolling over its sidewall during hard cornering. Below is a pic of the 285 PS4S on my stock 10.5" wheel for reference. The PS4S is actually slightly wider than the OE PSS the car came with. The PSS had an even more pronounced stretch. You can see how the sidewall has a slight angle. The stretch also allows for a more aggressive wheel offset. Audis have fairly conservative offsets, again it leaves room for snow chains. When I bought my C63 they made me sign a waver not to put snow chains on it. Not that I ever would, living in the climate I do, but it does tell you that the car is not meant to be a winter beater like the RS5. Personally I like the look of a stretched tire on a wider wheel. Just looks much more aggressive and gives it a much better stance combined with the more aggressive offsets.

BK_AudiFan

I have a 2023 S5 SB on order and cannot find the wheel width of the 20" 5-twin-spoke polygon design, bi-color wheels that come with the Black Optic Package. Anyone know the wheel width of these wheels?

Liquid Smoke

275 on 9" is fine, it just doesn't have the stretched/aggressive look but you get a more cushioned/square look. i think it looks fine too, doesn't look bulky or anything, fitment looks just right, and on those 20s with 30 sidewalls you want to have some extra cushion for comfort and rim protection, wheel bends and damage can happen easily.

those are 9" wide also, the S5 wheels just have a higher offset than the RS

s5_937

Helps a bit with ride quality but helps the most when it comes to stability at speed. A wider tire will be less prone to crosswinds and trailing on certain pavements at highway speeds. Drive a Prius with a 40 mph crosswind with factory 185 width tires, not a fun time.

superswiss

I'm not sure what you are getting at exactly. A Prius gets blown around more in crosswinds, because it weighs about 1000 lbs less, not because of the narrower tires. Wider tires are actually more prone to tramlining if that's what you are getting at, they are are also more prone to aquaplaning. Less weight per square inch. This is why for winter driving narrower tires are recommended as they are more likely to dig through the snow. OP is primarily asking about wheel width. A wider wheel does not widen the contact patch of the tires, so they are not asking to put on wider tires, they're asking about the width of the rim that the tires are mounted on.

BK_AudiFan

Thanks for that.

s5_937

This is not true about wheel. An Ariel Atom will be steady as can be due to wide tires and being lower to the ground. My old 300c ran on 225 width tires and would get blown all over the place at 80mph. My SRT 300 with 275s was as planted as an oak. Maybe 200 pound difference in the car, it came down to the tires.

You're accurate in saying wider tires are more prone to hydroplaning and are worse in snowy conditions. However, a wider wheel does, passively, widen the contact patch of the tire. Any given inch size tire has about 30 mm of play to be considered safe. The lower side of the 30 mm would give a bit of stretch and the higher side of 30 mm would give a bit of bulge.

Dan99

The 9" wheels position the side wall to provide more protection against curbing the wheel. It's still possible to curb the wheel, but it's not as automatic as it is with a wider wheel.