Tire pressure
I have the 20 inch AMG wheels with Michelin tires and my fuel cap says to do 31 PSI front and back. Last fill up I did was 34 PSI and I noticed the ride was a tad stiffer so I just stick to 31 PSI like my fuel door says. This usually helps with tire wear, fuel efficiency, ride comfort etc.
With that said, I'm running 33psi rear and 35psi front, car is always loaded with 3 toddlers weighing total of 100lbs and most driving is city where lots of intersection and turns, hence the 35psi on the front to compensate for the caster angle turning. Wear has been very uniform across the entire tread, both front and back. There were road trip occasions where we loaded up the car and ran 38psi all around.
And this is on the non run flat 21" Pirelli's




With that said, I'm running 33psi rear and 35psi front, car is always loaded with 3 toddlers weighing total of 100lbs and most driving is city where lots of intersection and turns, hence the 35psi on the front to compensate for the caster angle turning. Wear has been very uniform across the entire tread, both front and back. There were road trip occasions where we loaded up the car and ran 38psi all around.
And this is on the non run flat 21" Pirelli's








Use the gas flap pressures, plus or minus a pound or two to suit your preferences.
Then spend 15 minutes at a Discount Tire store every 3 months, and have them check / set the pressure you have chosen. This should be done seasonally at least.
If you want to be ready for weekend loads, and are willing to make the trade offs, have Discount Tire use that pressure when you do your periodic check.
Someday, when you're fiddling around with displays, find your TPMS and set it to the pressures you have chosen. That takes care of your "natural air pressure loss."
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Last edited by abcdef; Jul 30, 2022 at 03:21 PM.








The protocol is for the manufacturer to put their findings on the filler cap.
If your Audi and BMW don't have that info on the filler door, read the owners manual. Odds are their info is different from max pressure.




Not really, maybe because I have the extra weight on the back for the seats, now that I thought of it? I feel like higher psi rides more stable when going above 70mph.
Perhaps the higher max pressures on the fuel door flap for the 7-seater with 21" wheels is because those are run-flat tires? My 5-seater with 21" wheels has the non-run flat tires and the fuel door sticker notes max 31F and 39R.




Perhaps the higher max pressures on the fuel door flap for the 7-seater with 21" wheels is because those are run-flat tires? My 5-seater with 21" wheels has the non-run flat tires and the fuel door sticker notes max 31F and 39R.




I believe the feds require this reset capability, but I wouldn't swear to it.
Last edited by mikapen; Aug 1, 2022 at 04:12 PM.




If you do choose to not use max pressure, be sure to measure and fill when the car is completely “cold.” If you drive to the gas station and fill it up there, in all likelihood, the measured pressure will be artificially high as tires can increase in pressure quite a bit after it’s driven, which means it will be low the next morning.
Best time to check and fill your tire pressure is early morning in the garage after it’s been sitting overnight.




It's a good safety skill to master, no matter what Brand you drive.
I believe with the 3rd row option, no spare tire option is available, but as far as installed tires:
- If equipped with 19" or 20", it'll be run-flats and I'm not sure if they give you TIREFIT (I wouldn't think so since it already have runflats)
- With 21", non-run-flat with TIREFIT
The protocol is for the manufacturer to put their findings on the filler cap.
If your Audi and BMW don't have that info on the filler door, read the owners manual. Odds are their info is different from max pressure.









