Wilboy

Why are there two different recommended tire pressure stickers? I have a 2012 c250 with AMG wheels 225/40/18 front and 255/35/18 rear. The sticker in the door jamb identifies my tire sizes correctly and says cold tire pressure 36 front 41 rear. The sticker at the gas cap, however, says the recommended pressure is 33 front and 38 rear (does not identify the specific tire size).

Which of the two would you follow? I live in a warm climate 70-85 degrees all year. Any thoughts?

kevink2

My 1st thought is where are you, MBUSA does not list your tire spec, but 17" wheels only.

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The spec on the gas cap is likely for 17" tire set. In US, laws state the door plackard must specify tires sold with car, and pressures for diving with max capacity car weight.

If you solo most of the time, I'd suggest 36 psi F&R. You do want the same rear load capacity as the front's, so be sure both F & R have same load rating, like 91 of 93, etc.

.

mr inkredibul

I've never seen a rear wheel drive car with a staggered setup with the same tire pressure front and rear? Why would you recommend this?

Wilboy

Thank you for the info - makes sense now. I purchased the vehicle in California. It has the 18 in AMG wheel option.

I'll go by the tire pressure on the door. I was just surprised that the gas cap shows a different recommended pressure -- Mercedes and all car makers should have this kind of basic sticker information accurately reflected based on the specific vehicle, as equipped. Especially when applying the correct tire pressure is one of the few things owners are responsible for maintaining without driving into the service department.

I also wonder whether the sticker on the door is accurate based on the vehicle weight of the 2012 c250. I understand that the 18 in AMG are also an option for the c350 (a heavier vehicle) and standard on the C63. I'm curious whether the recommended tire pressure on the door sticker is the same for those vehicles with different weights.

acr2001

This is incorrect.

warren2024

Check on tyre pressure chart on door, I think you will find the different pressures are based on how many people are in the car (you should see solohetes of people on pressure chart)

jimmythegreek

u usually always want ur fronts a little softer than the rears. I run most of my wheels at 39/40 F and 42/43 R. Mind u I use aftermarket wheels tires on everything but I like it stiff. U want flex up front for cornering and potholes road bumps, and stiffer out back where its more straight line tracking for rear tires

B16RacerN2NR

This isn't always true. During a couple services, i've gotten CLS' (staggered wheels, RWD) with fuel door stickers that recommended the same psi all the way around. But you are correct, most staggered wheel set ups recommend different psi front and rear.

During a service, I just check the fuel door sticker. I'll go by the recommended "normal load" spec and add 2 psi to it. If it only gives me specs for "maximum load" I set it to that and nothing more.

I was told to use this method by my instructor while going through the MB STARt program and once I got hired into a dealership my Lead Tech told me the same thing. So I just stuck with that method unless a client tells my Service Writer otherwise.

Oh, I also stick with this method even with aftermarket wheels, different size wheels and/or tires. No client has complained about tire wear due to under or over inflation so far...

venchka

Based on several threads like this, the door pillar chart is useless unless you carpool with at least 3 NFL linemen. To date, the most accurate information across multiple brands of vehicles is the information on the inside of the gas filler door. My wife knows. She uses the gas filler door information.

If your tires aren't listed on the gas filler door, all bets are off. Which seems odd. Are your staggered AMG wheels a dealer installed, not exactly stock, item? If so, YMMV.

Good luck!

Wayne

wireless200

I'm wondering the same thing. Gas door pressures are different from door frame pressures. Gas door is a little less. I have a c-350 with the same wheels as you. I haven't seen a good answer yet.

kevink2

I recomended it for improved tire wear and comfort for the driver, based on the plackard max-load pressures, and assuming as I said, that the rears have the same load rating sidewall marking as the fronts, and that the driver goes solo most of the time.

The door plackard, by federal law, must show pressures that, when combined with tire load rating (91, 93, etc) , provide the correct load capacity at each tire (based on the max load calculation provided by the federal statute, where the maximum number of 175 lb occupants are seated and the trunk is filled to rated lbs). The mfg'r has the option of increasing these pressures, at their discression.

When the car is at the max-load condition, the rear tire sees a higher
load than the front tire. But when going solo, car nearly empty, the rears will be at much lower loads that the specified maximum condition, but not less than the max federal rating for the fronts. I therefore suggested running the rears at the same load capactiy as the fronts, meaning the same pressure if both front and rear have the same load rating ( 91, 93, etc.)

In the Federal Statute, "staggered" is never mentioned.

That's why I recomended this.

.

schvamf

I have a 2011 with the 18" AMG wheels and my door sticker says 39/39

venchka

Look closer. There are conditions associated with those numbers. Like load & # of passengers, etc. Possibly in graphic format. Those numbers are for the max. load associated with your vehicle and the tires installed during manufacture. You know, when you have the car full of pro football players or the trunk full of bricks.

Wayne

Stevedotmil

Speeds driven are also a factor. I have to check mine again but the other day I looked at it and could swear that it said if driven over 80MPH then fill front to "this" and rear to "that". Otherwise fill front to "this (which was lower)" and "that (also lower)". 2010 C300 Sport w/17's staggered.

kevink2

The door plackard is Federally controlled for just the maximum load condition.

I think alternative pressures for other conditions can be included at the gas cap sticker. Check owners manual about this. This would include 100 mph+ driving (higher psi), and possibly driving at less than max loading (lower psi).

.

venchka

"Only the Shadow knows."

Wayne

Kaewen

this is what i have on my gas cap.. but there isn;t any on the door, expect for my VIN number..
ooo i do not stay in the US

schvamf

You are correct it does say max load. On my gas door it says 36/36 so I assume that should be the normal amount to use.

Also since I have the 18" AMG wheels, is it better to have more or less pressure to minimize the risks from potholes?

Thanks in advance!
Frank

Ben'sBenz

My SA told me yesterday to follow what is on the fuel door.

venchka

He learned from my wife.

It ain't rocket science or brain surgery folks.

Wayne

Sportstick

When all else fails, read the directions....here is what the Owner's Manual shows:


Your vehicle is equipped with the Tire and
Loading Information placard located on the
driver’s door B-pillar (Y page 262).
The tire inflation pressure should be checked
regularly and should only be adjusted on cold
tires. The tires can be considered cold if the
vehicle has been parked for at least 3 hours
or driven less than 1 mile (1.6 km).
Follow recommended cold tire inflation
pressures listed on Tire and Loading
Information placard on the driver’s door
B-pillar.
Keeping the tires properly inflated provides
the best handling, tread life and riding
comfort.
In addition to the Tire and Loading
Information placard on the driver’s door
B-pillar, also consult the tire inflation
pressure label (if available) on the inside of
the filler flap for any additional information
pertaining to special driving situations. For
more information, see “Important notes on
tire inflation pressure” (Y page 267).



I've added color and bolding emphasis to the MB wording to make the point. Driver door label info is for normal ongoing use. Fuel door info, if different, is for special situations as described.

Jim K

Our new 2012 C350 has the same tire sizes as our 2008 C350. The gas flap shows 30 front 38 (!) rear. I've never owned a car with that differential or one with 38 psi for the rear. The car rides like a buckboard, very hard, not at all like the 2008. I've inquired about this situation and wonder what the combined wisdom of this group is. My belief is M-B has jacked up the recommended tire pressures to improve gas mileage. I'd give up some gas mileage to keep my teeth from breaking. P.S. The car rarely has more than 2 people in it and we don't carry heavy items in the trunk. Any of you had a similar experience with the 2012 C350?

Sportstick

If you read the owner's manual, you will find that the recommended pressure for typical usage is on the label on the driver's door jamb, along with the car's VIN and point of final assembly. The manual explains that the gas door values are for special situations. Read my post #21 above.

Jim K

Actually, it's the reverse. The door jamb is for higher speeds (e.g., Autobahn). The manual is wrong (again). (It's also wrong about the homelink for garage door opener) For U.S. cars it's the inside of gas flap that is the source. But that's not the issue I'm asking about. I guess no one has experienced the especially hard ride the 2012 higher pressures (especially in the rear) induce. I'll just experiment.

Sportstick

Your information is incorrect. The tire pressure for normal usage is required to be posted on the B-pillar per Federal Motor Vehicle Safety Standards (FMVSS), as regulated by NHTSA. Open the door on any vehicle sold in the US and find the same, but few have any information on the fuel filler flap. The fuel flap is an additional optional opportunity for the manufacturer. The fact that the fuel door provides a higher pressure is the direct evidence that it is for prolonged higher speed usage, as that environment is the type which requires higher psi.

If you adjust your tire pressures to the B-pillar values, you should find a more comfortable ride.