What should be the tire pressure for the 18” wheels and all season run flat tires for 2020. 38 psi all around?

 

It's on your fuel door

 

I think fuel door will say 36, 38 is fine too.

 

36 is for winter tires on 18" wheels, as I understand it.

Someone explained to me that the pressures associated with the M+S symbol on the fuel door are for proper snow tires, not all-season tires.

When I took delivery, the dealer had my tires at 41 psi all around (18" all-season RFTs). I can't remember what is on the fuel door.

 

http://mercedes-benz.custhelp.com/ci...0pressures.pdf

 

Thats a generic fuel door info. page.

Not sure what you were trying to share there.

To clarify, I was just stating that I couldn’t remember what the various values were on my ‘20 C43. Only that they were different than my ‘18 C43, and also different from the values on the fuel door of a family member’s ‘17 C300 that has the same exact size and model of 18-inch RFTs.

 

I think he’s showing us where the tire pressures are shown on the car.

 

c300 doesn't have a v6 upfront - weight/load change necessary pressures.

this car seems pretty forgiving on specific pressures. I ran anywhere from 36 - 43 up front and tire wear was more or less the same. I always keep the rear 2 - 4 psi shy of what the front is set to.

 

Whats the reason for less in the rear?

 

Front of the car is heavier because of the engine and the fat driver.

 

I will give this try. Thanks.

 

41 Front 33 Rear

 

41 Front 33 Rear?? is this for a sedan , coupe or cab? Either way seems like quite a spread? Where did you get these recommendations?

 

The M-B recommended pressures are for the runflat tires. Many, including myself, have dumped the runflats for conventional tires. I suspect there'd be a different recommendation for this different tire type, but I don't know what it would be. (And that's not really the OP's question - a minor hijack).

 

That's for the sedan, with the 18 inch run flats. Those recommendations come right off the fuel door, for two occupants and normal cargo load. Rear pressure recommendations go up for more passengers or more cargo weight. Ran that with the run-flats, and tire wear seems normal. On non-runflats, I ran 37 front, 36 rear, and had no issues.

 

My OCD got better of me and put 36 psi on all 4 this summer on 19s. Will probably do same for winter 18s and see how it works out this year. If not going back to 37 front 35 rear.

 

What year is your sedan? I have a 2020 and it shows 36 for front and 35 for rear, for 2 with normal load.

 

yes I checked also, so pretty much 36-37 all around is fine. Mine is 38 right now.

 

Mine is a 2019. That 36f 35r that you are seeing...is that next to the M+S rating. That rating isn't for the 18" runflats, but for snow tires (though just fine for any non-runflats really). The ratings for 18" and 19" runflats are different on my fuel door, and I'd be really surprised if that drastically different for the 2020 models.

 

Tire pressure can change drastically depending on outside temperature. For the 2020 C43 specifically on stock tires, I run 35 rear and 37 front. In 90 degrees+ weather in California right now, the pressure goes up to 38 rear and 40 front after about 15-20 minutes of driving, which is where I want it to be at. Depending on the driving characteristics that you want, I believe these numbers can be flexible anywhere between 1-2psi and it shouldn't be an issue. In winter, I assume I will do 37 rear and 39 front since I don't expect the tires to heat up as much.

 

haha Im adding a pic as proof. 36F 35R for the most soft setting on 18s.

 

Ha! Well then, I'm certainly surprised. Not a single psi recommendation on yours matches up to what's on my fuel door. I'm left to wonder why there would be such a drastic difference between 2019 and 2020 model years and what precipitated the change.



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hmmm,...wondering if your sticker was applied as a mistake? I do recall the coupe having quite a spread between the front and rear tires - but I do not have a picture of it. Anyone else can share/check on this post already?

 

the last 4 digits on your sticker is 66 11 mine is 65 11. It's the numbers that start after the "A", its like a parts SKU number for Benz.

 

The C43 tire pressure question is one of the greatest mysteries of the universe.

My 2018 sedan’s fuel door had entirely different pressure recommendations than my ‘20 does. Not surprising for some reasons. And my ‘20 has the same 18” Conti all-season RFTs.

May go through my photos to see if I can post a comparison.

Some people say that the R18 values on the fuel door apply to cars with the all-season (AS) runflat tires (RFTs).

But my AS RFTs have the M+S symbol. Some have said that the M+S symbol on the door only applies to “true” winter tires.

If that’s the case, that’s a confusing decision by Merc to not distinguish as such, as on my ‘18, I assumed that the M+S values were what I should follow. So I ran 36 all around and got good wear.

Dealer pumped me up to 41 PSI all around when I took delivery of the ‘20 in February. I’m letting that come down now (only have 500 miles).

And I want to know whether I should stay at 39 all around or lower to 36 F, 35 R.