PsyQ7

Don't get me wrong, it's a subtle difference, and I'm sure there are other factors like tire wall, materials, temp variations, but it does feel more comfortable and certainly quieter than the Contis I had on (To clarify, I don't have air suspension and am a V'red. fanboy).

The ride height difference hasn't been noticeable and certainly no rubbing of any kind - I compared the change in sizes against all the largest OEM options I could from the SQ7, SQ8, RSQ8 etc. and this was similar or less than some of those I recall. My eldest is 4 and can just about climb in/out herself, no change in her ability to do so w. the extra height, more just that she's fascinated by the 'new shoes' and the fact that the blue stripe on the tires to indicate new tread matches the car...

Overlaying the two setups as closely as I could in the below photo, you can see the gross height change visually (bottom plus top). Then doing the quick math...
40% of 285mm = 114mm, and 45% of 285mm = 128.25mm, so an increase of 14.25mm either side of the diameter, or 28.5mm total 'height' increase. Multiply 2.85cm by inches conversion factor of 0.393701 gives a total increase in height of 1.12". Thanks, I hadn't considered the value in inches, just cm.

Our clearance from the top of the roof bars to the retracted garage door is ~6", so of course less now (I'll measure shortly)... ...something to consider.

Q72023

Greetings

Stock on my 2022 q7 285/40 summer tires on the 21" wheel.

Was thinking running 285/45 height snow tires . If we switch to the 45 height (on the existing wheel), I know the speedo will be off a little bit. Is there anything else I need to worry about? Seems you did it no problem?

Thanks!

mhoran89

why? go with 275/40/21. I just did this and it is narrower which will be a little better in the snow and they are much less expensive. 1.22% difference from the stock 285/40/21 tires. let us know what you end up doing and best of luck.

Q72023

Thanks for your perspective. Why you ask? Bc I can buy 4 Blizzak Run flats for 60 percent off right now - end of season in the larger 285/45 size. Widlth of tire is the same. Diameter is 3.6 percent larger than OEM. 275/40 is smaller, only 1.1 % smaller as you indicted but I can't buy runflats that cheap and the tire is 10.83 (275) 11.22 (285) 0.39 (10) 3.6% narrower. Not sure if that will be an issue in seating the tire on my OEM rim - prob not. Just wanted to answer your question.

Based on other answers from other boards, looks like the 3.6 %larger tire works just fine. But hey - I'm far from a tire expert, hence my post. Thanks for your input!

mhoran89

a 275/40/20 tire fits on a 9-11" rim and the OEM 21" wheels are 9.5" wide so you are perfectly fine there.
run-flats are still really expensive, ride like trash, are very heavy, and shops won't want to repair them if you pick up a nail a lot of the times. they are not worth it for me. there is a reason porsche doesn't equip any vehicles with run-flat tires, because they prioritize the driving experience more than anything else. i stand beside them on this.

FYI the experts say you should not deviate within 3%. I am sure you will be fine though.

MarkJames

Did you put 275/40/20 tires on your 2018 Prestige? I’m looking at options for non RFT because I agree that nowadays they are rarely needed. My wife always had it in Comfort mode, so I felt it was too floaty (air suspension), but after taking over the car and putting it in Dynamic mode it’s much better. When you go non-run flat does it change the feel a lot?

mhoran89

no. 275/45/20. the non run-flat tires ride quieter, softer, and are more responsive. they are much less expensive as well. one of the first things I did to both my 2017 and 2018 when I got them was get them off run-flat tires ASAP. feel isn't really changed. what you will notice is the car will ride way better with new tires regardless. if you go to non run-flat it will be an even more pronounced improvement. I also have run snow tires on both cars in the winter. I have ran everything from a 255/60/18 to a 285/40/21 on these cars, and many sizes in between.

long story short if you are having issues with 20s go from 285/40/20 to 275/45/20. if you are sick of the 21s in a similar "unicorn size" go from 285/40/21 to 275/40/21

MarkJames

Any specific brand recommendations? I live in the Atlanta area so all seasons are needed, but snow is rare. Looking for a tire that drives well, wears well, and doesn’t cost a fortune.

keg97

Several of us have the Michelin Pilot Sport All Seasons. VERY happy with them. We had two sets of Continental All Seasons that came on the OEM 20's and we were very happy with them as well. Assuming wear is similar, a light preference to the Pilots though.

mhoran89

can never go wrong with this tire.
https://www.tirerack.com/tires/tires...omCompare1=yes

they don't make the michelin PS 4 A/S in 275/45/20. they do in the 285/40/20 but it is really expensive.