Correct Tire Pressure - multiple choices from three different labels

[RaymondP]

Once again, manufacturers are doing their bit to make simple things complicated and confusing. In this case setting the correct tire pressure.

My new (2021) Merc GLC300 4Matic has no less than three tire pressure labels. On the door there is the "official" Mercedes label referencing Stuttgart. Right next to it is another label, possibly by the tire manufacturer, as suggested on the visual. The vehicle comes with Pirelli run-flats. Another conversation, so I won't go there! And finally, on the gas tank door flap is a third label. This one references the lower pressures of the three at 32psi for both front and rear.

Is this a result of conflicting regulatory requirements for different regions of the planet? I'd be happy with just the one label. I can follow directions!

I know I am being a bit flippant here, but if you have spent any track time you will know it is important.

 

[Imp4]

I know I am being a bit flippant here, but if you have spent any track time you will know it is important.

Are you tracking this car?

 

[BMWTurboDzl]

I know exactly what you're talking about. On our C300 I would go by the door card or the user manual because it referenced the actual size of the tires which were on the car. Complain to MBUSA?

 

[RooflessVW]

35psi and send it.

"Good enough" for 90% of the cars on the road.

 

[BHopkins]

I feel your pain! My E350 has a label in the driver door jamb and another on the inside of the fuel fill door. It appears as though someone has crossed out the label in the door jamb with a yellow marker. The previous owner? IDK.

I am accustomed to the tire pressure being listed on a label in the door jamb, so I tended to want to follow the information on it. But when I read the Owner's Manual, it refers to the label on the fuel fill door. So that is the one I have followed. It is reassuring that most others, on the MBWorld discussion board, refer to the tire pressures on the fuel fill door also.

Have you checked the Owner's Manual to see if it references one over the others?

 

[vavavroom]

Multiple labels are confusing but they are probably for different countries, different speed limits, load ratings, and different regulations. I'd go with the fuel door label as the most relevant one and add 4 psi to all four tires for more spirited driving and see how that feels.

 

[The Critic]

On MB vehicles, the pressures for normal load are usually on the fuel door.

Pressures listed in the driver door jamb are typically for max load.

 

[RaymondP]

Are you tracking this car?

No. Just referencing experience on a previous car!

 

[RaymondP]

Will check the manual in the morning. Could there be a fourth option....holding my breath? Seriously, you would think the dealership would remove or indicate the incorrect labels. Two differing labels is bad. Three?

The gas tank door label of 32psi results in a very bouncy ride. Also the only one that does NOT differentiate between front and rear tire pressures. Not what I would expect for an SUV/truck. Maybe I should add them all up and divide by three and use the average? OK....getting silly now!

 

[PimTac]

Why not just use the Mercedes reference?

 

[RaymondP]

As the original creator of this post, and to end the suspense I checked the owner's manual. Seems to address everything relating to correct tire pressures. but appears to go to great lengths to avoid highlighting specific tire pressures, even featuring an image of the gas tank label with the numbers blurred out. Instead, readers are directed to the gas tank flap for pressure settings, plus the door pillar label for maximum pressures and load info.

As mentioned, on the label mine recommends 32psi for normal loads and maximum settings of 35/42 for front/rear of a fully loaded vehicle (5 passengers plus luggage). With a single occupant, the driver, for 80-90% of the time, set at 32psi all around the vehicle bounces disconcertingly. As a result, I will be using settings significantly closer to the upper limits that seem to resolve this issue.

 

[Wolf359]

Your other problem is the run flats. Most people hate them and switch to regular tires but then you have the problem of trying to locate a spare or you just risk it. My 2008 E-350 also had the two labels, one on the driver's side and the fuel door. No third as it never came with run flats.

 

[The Critic]

I’m waiting for someone to say, “none of this matters, just run the sidewall maximum.”

 

[andreigbs]

No matter which brand, run-flats feel and handle poorly. There's nothing you can do about that except ditch them and get normal tires.

For reference, neither of my diesel SUVs come with a spare tire and both have non-RFT/normal tires. The difference in ride is night and day. In nearly 5 years of running these tires I have yet to experience a flat (I am prepared, with a patch kit and small compressor).

Oh, and cold tire pressure on both are set to 36 psi.