I am sure this questions has been asked before. I am new to run flats and getting a direct answer on what the actual tire pressure should be has been interesting. The manual says use the values found on the fuel door. The service advisor says use the values found inside the driver door. The driver door has 2 tags with different information. Which value should be used? The vin sticker has 35/42 The fuel door has 32/32 and the extra sticker has 39/46 The tire pressure when the car was delivered was 42 all around. I want to get the inflation right to see it it resolves the twang in the front suspension before I return to the dealer. The car has 600 miles. I have seen the other treads on the vibration subject just want to cover the ordinary causes before I bring the car back. Meanwhile the dealer struggles to get the chatter out of new wipers.

 

One would think that a company making vehicles as long as Mercedes has, would be able to convey the correct tire inflation information on all three labels.
As many on the board have suggested, I use the inflation numbers listed on the fuel door.

 

Tire pressure isn't as simple as just one psi.
normal driving is considered driver and passenger, the best tire pressure depends on how much the vehicle and passengers' weight combined.
There are max load ratings listed inside the door. If you have 4-5 passengers and they are heavy then the max load tire pressure should be used
for best tread wear and stability. Keeping side walls in proper shape.
They also list adding 4 pounds if driving over 100mph. That doesn't mean just driving that very seldom that is for people on like the autobahn
where the driving is long distance and mostly over 100mph.
The 39 and 46 psi in the door label is the max pressure you would use if driving over 100mph with a full load 5 passenger's maybe computers or
luggage in the rear. If not driving over 100mph then best psi would be 35/42 for the tires to stay in best shape.
When cars are shipped form over seas or setting for some time on a dealers lot they will raise the tire pressure, Mercedes uses 42psi, that is
to keep the tires from developing flat spots, The dealership should have adjusted the psi to the 32/32 before delivery or 35/42 if you drive with full load all the time.

 

​​​​​​The confusing stickers are required by the Feds.
Could be a high school art class, commissioned by a committee established by a bureaucracy established by Congress.

Gas flap, as you said.

 

The best tire pressure for run flats is 0 psi. Meaning, remove them entirely and get regular all-season tires that don't ride like bricks and rattle your car's bolts out of place.

(Sorry, I still have leftover trauma from the Goodyear Eagle run-flats my GLC came with. Worst tires ever.)

 

I’m a long term 20 yrs- C, E, GLC MB owner , never leased, and have just replaced tires ar 38K with the same Pirelli RFTs. I’ve had over 150K on all my MBs when traded in and always had them dealer serviced. If you can afford a Mercedes Benz you’re supposed to be able to pay the maintenance costs, which are clearly explained by MB. That’s an expense that a person should know before they choose a vehicle anyway, unless they are just wealthy and acting on impulse or are so inexperienced and naïve that they just never thought to look into what it costs to maintain an expensive German car.
Don’t get sucked into the Run flats are horrible rhetoric. Your driving style and personal opinion of benefit/compromise is what will matter most as time rolls by, and welcome to German vehicle ownership. They over-engineer everything including the details on which tire pressure to use according to possible circumstances. 32 is, per my experience, too low. For my purposes, I keep all four tires at 38 psi. although if I were going a a long drive with luggage and 2-3 passengers I would increase to 40.

The vibration when crossing expansion joints or road ripples is due to programmable suspension tuning and it can be corrected by your dealer. Make an appointment for a warranty claim, requiring a loaner, and tell your service advisor when dropping off that you will not be scheduling a pick up until they have fixed the issue and tested the system, AND that you will expect a test drive with the SA or Service Manager before accepting your car. This may take a couple of days for them to get it corrected but it can be corrected. Btw keep the keys to your loaner until you’ve tested and accepted your car back.

One of things I was most happy about was finally having RFT tires. I knew they would have a stiffer feel, but the security of being able to keep driving instead of sitting on the usually non-existing shoulder while maniacs blaze past, possibly during a winter storm while no roadside help is available anyway, is a compromise I’m happy to accept. That and knowing that if my wife is alone and has a flat, she can continue on ( under 50mph) without destroying a wheel. I’ve changed enough tires in my life.

lastly, new wipers that chatter on a new car are possibly due to residue from the final prep before delivery. They want to wax everything in reach. Try cleaning your windshield with hot water and Dawn detergent. Clean the blades themselves. Mine quieted down after a few rainstorms.

 

Yes, but run flats ARE, in fact, horrible.

 

I generally go by what psi is stated on the fuel filler door. However, I personally find that 32 psi is too low and 42 psi is a bit on the high side. Somewhere in the range of 37 to 40 is the most comfortable for me. I too am not a fan of RFT. It is however reassuring to know that you don’t have to worry about being stuck on a dark desolate road knowing that if you don’t change your tire you will need to buy a wheel. For a MB that can get expensive. I have the optional spare tire , $200 , just to give me some additional peace of mind. Even though Mercedes will not repair a simple flat on a RFT , there are many reputable tire places that will. Having a spare call also save the RFT from being destroyed, that’s a savings of about $300. I’ve had RFT repaired and they lasted until I traded in my vehicle.
My car is quite new , and very minor wheel vibration is noticed. At this point I opted to not bother bringing it in for service to correct it, it is very minor compared to a loaner I was given when I brought my other vehicle in. There the vibration would persist for at least 10 to 15 seconds after the bump was passed. In the past my daughter had a 2017 GLC, I had a 2018, and now I have a 2022. This newest one seems to ride the best compared to our previous nearly identical cars.