gta1216

I don't know if it a coincidence or what, but every time my tires deflate, all 4 of them deflate and around the same amount of pressure is lost. My tires are usually inflated to 45 psi. Whenever the low pressure light comes in, it's always for all 4 of them, and pressure is usually around 35 psi.

plat27265

How many days does it take to deflate from 45 psi to 35 psi?

gta1216

It was a month ago that I last inflated the tires. I'm not sure if this is normal or not, but I'm more surprised that all 4 tires list the same amount of pressure at the same time. And every time when the light come on, it's always all 4 tires.

greasykid

My dealer & owners manual specify 33psi all around. I know that the drivers door says 45psi. I believe that 45 psi is max tire pressure.
As for tire psi going down on all 4 tires. Sounds like ambient temp change . An up or down change of ambient temp of every 10 degrees will raise or lower tire psi 1lb. Example: A drop of 30 degrees in temp will lower each of your tires 3 psi .Sames goes for hot or cold tires. ALWAYS take tire pressure readings when tires are cold. Also set TPM when tires are cold.

plat27265

45 psi on the door jamb sticker is the tire pressure when the car is fully loaded. For up to 3 passengers, the Owners Manual specifies a tire pressure of 32 psi all around (for 17- and 18-inch wheels) and 33 psi all around (for 19-inch wheels).

For a full load:

17" and 18" wheels: 33 Front / 36 rear
19" wheels: 44 front / 46 rear

greasykid

Correct. As I have 19" wheels & not a full load 33psi works for me.

PNW Etron

I'm happy with the simpler indirect measurement employed by Audi. It's much easier to swap out snow tires/wheels and much less to go wrong!

Tccox

Odd, my 2020 Q3 with 19” wheels states 38 psi