NickTH

My wife's 2015 E400 door plaque say tire pressure should be max psi 35 front & 45 rear, & gas cap says normal 33 & 36, max 35 & 45.

We always had 36 psi cold for all tires.
Today dash shows: correct tire pressure & had 3 tires in orange color at 36 & one ok at 37 (tires a little warm).
I refilled all tires back at 36 cold.
My wife reset tire warning on dash.
Looks like everything OK now.

So what's the correct/proper cold tire pressure ya'll using?

Thanks,

belarus27

i do 32 front and 34 rear e550 2010.
18s amg wheels

SEC1939

does it have the fine print on gas cap door stating -3 psi at speeds under 100 mph? Mine does. I have factory 17" on mine. All were under inflated so I went up to 35/45 the backed off when I saw this.

fosterelli

I think (could be wrong) that the gas cap is generic for your make/model...the sticker in the door is specific to your exactly built vehicle (with the size of tires it is equipped with...some have different sizes and some are also staggered). I'd use the door sticker as your guide.

I use my door sticker recommendations and never have an issue. I also run the staggered tires w/ OEM Continentals.

The G Man

I always wonder why there is a such a big difference in tire pressure from front to rear. With such a difference, the tires will never wear evenly. It seems to me that the front should have the higher pressure since it bears more weight. BMW recommend the same set up, rear tires pump to a higher pressure than the front, for improve handling. On a RWD, that would make some sense, but in an AWD car, its pretty hard to fish tail the rear end. I usually just set the rear tires the same or about 1 or 2 PSI higher than the front.

KEY08

The manufacturer believes it is safer if the car maintains its understeer tendencies, and the lower pressures up front do just that. I like to run my Contis at 35f and 38r.

The G Man

That theory is all fine and well on the track, but on the streets, it is not needed in my opinion. I cannot remember the last the time my rear end fish tail. I think it is more important to me that the tires wear evenly. Do you really think a tire with 45 PSI has better grip than the same tire at 35 PSI?

KEY08

Understeer really is safer on the road. We are not talking racetrack here, where understeer is not necessarily desired. Lots of reasons for it, but I don't need to write a novel. Fill your tires with air any way that works for you, I was just trying to provide an answer to your question.

BenzMan369

The explanation for the difference in the gas cap pressures and the door plaque pressures should be explained in your manual. It is, in my coupe's manual.

Basically, the gas cap pressures are for "normal" driving conditions with "normal" loads. The door plaque pressures are the maximum safe pressures and will cover the car's rated performance limits and the maximum load the car is rated for.

That said, folks tend to set the tire pressures where they are most comfortable and/or provide the type of handling the driver wants.

SEC1939

Thanks for the help. Not sure anything can make mine with run-flats ride better. Once worn I'll go to traditional tires.

BenzMan369

I hope your kidneys hold out longer than those run-flats. This coming from a guy who's been enduring an E Coupe's sport suspension and AMG sport trim package for 5 years - without the run-flats.

I can't complain; I knew exactly what the ride would be like before I ordered it. And the doggone little car makes up for it in so many other ways. Nevertheless, next one will more than likely be a sedan - and no run-flats.

Happy motoring.

The G Man

The Bridgestone drive guard runflat has been rated very high for ride comfort.

SEC1939

Good to know. Figure I have a good 40k miles left on what I have. I'll either grow used to them or work hard to wear them out faster then decide next step.

thefisch

I set mine at the midpoint between normal and max. That way I don't have to worry about what I eat for lunch that day.

El Cid

I run my tires at 2# over the recommended normal. My car calls for 30F/35R, so I run them at 32/37. I monitor the tread wear to make sure wearing evenly.
I have an old plastic label maker and I make tapes with 32F/37R on them and put one on door pillar and one inside gas flap. Do something similar with my other vehicles,
I also have a small note hanging next to my tire pressure gauge with the TP's for each vehicle. That way I can check and adjust TP's without even having to unlock the vehicles.

jonUF02

No one mentioned that the dash computer warning thing can be set to any baseline number that you desire.

Airmousam

I run 35 all around

Edward993

E350 with stock-sized 245/40-18s: I run 34F/35R, seems fine WRT nothing feeling strange and getting decent road compliance.


However, I will drop the fronts to 32 and see what I think, again in terms of road feel and ride compliance.


Edward

netdvn

E350 with stock sized 245/40/18 front and 265/35/18 rear. I run 34F and 43R. The life of my original tires was 50K miles. I check tires pressure monthly.

ElisTwoCents

That's about where I run mine as well - Im installing 19s tomorrow so I'll see how those pressures feel

Tump43

I run my E350 w/ 18 inch rims at 38" psi at all four corners. Being an all wheel drive vehicle, the car just feels better to me with equal pressure in all tires . I used to run 35 psi, but the car feels better to me with 38-40 psi (meaning that it runs at 40 to 43 psi depending on temperature). At my last service the dealer set the pressure at 43 psi rear and 36 psi front. That felt horrible. I don't like the understeer.

The gas flap calls for 35 psi for regular driving/loads and 40 psi for high-speed/full load pressure.

MB recommends that 18 inch rims run higher pressure than 17 inch rims.

dbldpr

mine are at 32psi in all 4. I think I get a more comfortable ride but then I only put about 800 miles a year on the car.

cc16177

800 miles a year?! I drive 800 miles a week easy... lol


I am equally jealous and sad for you :P

dbldpr

Last car we got rid of was 15 years old and had 28,000. When we bought this car dealer said I had to bring it in at 12,000 for oil change. I told him I would see him in about 10 years. He said no. I had to bring car in at least once a year. I said Ok. I will be putting about 3,000 miles on the car this year because we will be going on vacation for a month or so. Last trip we got 30 mpg. Best I ever got on a vacation car. Very impressed.

jahquan3

I have a staggered set and run 33F 40R.

I've had STS set them all the same at 35 before and Benz set them at 30F 35R. So I kind of just go with what I feel most comfortable with. The weather is so inconsistent up here so I often have to put more air in it every few months.

Anyone try nitrogen?