Hey all,
What tire pressure are you running while daily driving with only you and maye another in the car? As received from the dealer it had 45 psi in front and rear, a little high.

The door jam states 42 psi front, 41 rear.
The fuel door states 35 front, 31 rear for 155 mph, lol. Then higher pressures for more people and higher speeds! Where do they think I'm going to be driving?!

Do you go by what's on the fuel door? Asking because it's so far off as received from the dealer.

Thanks, NIXDSG

The fuel door lists the correct pressures to use. The door sticker in the US only lists what's called the max load pressure, which is for when the car is fully loaded and you are going to drive over 155 mph. The door sticker is useless in the USA, but it's like this because of the Firestone incidents in the 90s. Running the door sticker pressure is the safest, but makes for the worst ride quality if you are just by yourself and likely causes uneven tire wear in the center of the tire, because the car isn't heavy enough if not loaded fully. The pressures are so different, because the forces on the tires at speeds over 155 mph are so high that the pressure needs to be significantly higher to avoid overheating of the tires. It all comes down to the tire deflection, which causes the tires to heat up.

4th MB with run flats, current is 21 GLC43, Goodyear run flats. I am running 29 psi for a better ride, even on a trip (80+mph 3 hrs) tire temp. is around 125F. If this makes them wear out faster, great! I maintained about the same pressure on my CLS 550, no tire wear problems.
\p.s. this is Tucson, AZ