MjkE350

Hi All -

I picked up a new E-Class a little over a week ago and I have a tire pressure question. The tires were WAY over inflated when I picked up the car. ( I didn't know until I left the dealer after delivery)

I have the twin spoke 19 inch AMG wheels and in the door it reads:

Fronts MAX 37 PSI
Rears MAX 45 PSI

In the gas cap (which the person at the dealer said they are instructed to follow the PSI settings in the gas cap)

It says all 4 tires should be at 32 PSI.

Now the sticker inside the drivers the door has the right height/ width of the tires on my car but the PSI settings are very different.

Which settings do you guys follow?

As a side note, even at 32 PSI all the way around, where I am at right now, I notice a little vibration in the car, seems like it is coming from the left front. Could be not a smooth road but I am noticing it often. Does anyone else with the 19's notice this?

thefisch

I follow the gas cap ranges. What does you door placard say?

MjkE350

Door placard says:

Fronts MAX 37 PSI
Rears MAX 45 PSI

Gas cap says 32 PSI all the way around.

thefisch

Sorry, I misread your first post and thought those were the current pressures. The placard gives you the max which is if the car is fully loaded with max cargo. The gas cap is giving the pressure for a normal load. I would just run it at the gas cap levels.

It will be interesting to see what others post what their door placard and gas cap sticker read.

MjkE350

Thanks! I am interested to see as well given the large difference between the door placard and the gas cap.

larrypmyers

The pressures indicated on the drivers door jamb are with the vehicle at max load.

Pressures on the inside of the gas filler door reflect several different size tires to include normal and max load.

Normal tire pressure for vehicles with 18, 19 and 20 inch tires is front 32 rear 32.

Optimally tire pressure should be checked first thing in the morning before the vehicle is driven.

The above is from a 2016 GLC.

joshg1001

All dealers will have over inflated tires because then they leave the factory, they are preparing the cars for being stationary for long periods of time, either on the boat or at the dealer lot. 32 seems rather low to me, it can't be wrong if its on the label.

shortspark

The psi recommendations found at the gas cap door and the drivers door jamb have been different forever on German cars and are due to agreements reached between German auto makers and tire manufacturers. There are qualifying factors involved such as speed, temps, loads, etc. but the general rule is you go by the gas cap recommendations for "normal" driving and the door jamb recommendations for "spirited" driving or driving with a heavy load.

Mercedes cars spend their life on the Autobahn where high, sustained speeds put tremendous stress on tires. To minimize tire deflection under these conditions requires an increase in tire pressures and those are what you find on the door jamb recommendations. Americans seldom need such high tire pressures because there are few places in the US where that kind of sustained, high speed driving is permitted.

I own a 2017 CLS 550 with that potent 278 V8 twin turbo and it goes like the wind but I don't drive it that way for more than a minute or two on isolated stretches of highway. Accordingly, I follow the gas cap door recommendations plus a pound or two. Prior to this car, I owned an ML350 SUV which was a completely different kind of vehicle. I also went by the gas cap door recommendations plus a pound or two (unless I had a very heavy load in the back end). If I owned an E class I would inflate my tires this same way as I have done with my other Mercedes cars.

Here is a good article from Tire Rack that addresses this subject:

http://www.tirerack.com/tires/tirete....jsp?techid=72

MjkE350

Thank you everyone for the helpful responses.