Rich9300

I have a 2019 E53 AMG Sedan. Best car I ever had, bar none. I run Michelin Pilot Sport 4 S tires in the summer and Michelin Pilot Alpin 5 winter tires (Chicago area). The summer sizes are standard, 245/40R19 in front and 275/35R19 rear. The winter sizes are 245/40R19 all around.

Recently I was out of town in Minnesota and one of the winter tires was destroyed (totally bald spot in the middle). I had been running with the gas cap cover pressures, 41 psi in front and 42 psi in rear. Since the tires were old by this time I ordered a whole new set of Alpin 5's from the out-of-town Mercedes dealer. When I drove away I saw that the pressures were only 36 psi all around. I went back to ask about it, and was told that this dealer believed in using 36 psi because the official pressures were too high and the tires wore badly. I then did some online research and found that the european spec for my car with my size tires are 36F/36R for the winter sizes and 36F/39R for the summer sizes.

I tend to believe the european specs are better, since I think Mercedes might have been stretching the pressures in the USA for better gas mileage. Thoughts?

Keith66

Your out-of-town dealer was right IMO. I run mine 36psi (cold) all around and I've found it to be more compliant (better ride) and handles better compared to 40psi+ (cold).

Running 40psi+ (cold) is primarily the suggested pressures if you spend the majority of your driving with 5 people and their luggage in the car (max load).

Keith66

You may want to check out this thread also:

https://mbworld.org/forums/w213-amg/...y-driving.html

Rich9300

Thanks for the feedback!

YYC53

I'm amazed at how different your pressures are vs my '20 E53. I am running 36-37 all around on PZ4 run-flats, it's better but I still hate these tires more than I thought possible.

Rich9300

The pressures I have quoted from my gas cap cover are for light loads, that is, summer 41 psi front and rear, winter tires 41 front and 42 rear. The pressures for heavy loads are 44 front, 45 rear for summer, and 44-49 for winter tires. Did Mercedes realize their mistake on 2019 models, and correct for 2020?

The standard tires were run-flats. Mine are not. I changed them out to conventional performance tires.

YYC53

Here's the '20 pressures, E53 as well. Same same.

49 psi on winters...I dunno what the max is but it's 50 on most summer tires.

Keith66

I'd like to add that my input here is just my opinion based upon my experiences with this car. It doesn't necessarily mean I'm right.

Manufacturers' specifications are never guesswork and they are determined through extensive engineering and testing for all common scenarios so it's difficult to say they are wrong, but end users like myself like to tweak things for my particular situation.

Just something to keep in mind that variances from manufacturers' specs may involve a certain amount of uncertainty.

Rich9300

I would like to think so, but I can't understand why european specs are different from USA's for the same car, and not just by a little - 5 psi in my case for the fronts. At least according to what I've found on wheel-size.com.

Keith66

Agreed, I don't know either. I guess they have better air over there, lol.

YYC53

Inevitably a different formula for the pressure is being dictated by the EU, US DOT or whoever. The obvious difference is that we don't have roads with unlimited speeds in North America. Average temp probably plays into it, perhaps seasonal range in temps. I'd guess European market tires have differences to NA tires depending on manufacturer and whatever rules apply.

For example Calgary has a real range in excess of 60 deg C through a year, max possible is closer to 80 deg C. Florida so far as I can guess has a 10 deg range! Just making the point.

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Ed99

I run between 42-46psi on both winter tires and summer's and I think that is a sweet spot.

YYC53

Which tires?

Ed99

Pirellis for my winter set up and Michelin PS4S for summers

SerottaD

On the racetrack, proper cold tire pressure is determined by going out for a few laps and rechecking the tire pressure immediately after pulling into the pits. If memory serves from my time pitting for a friend racing AFM (motorcycles), I believe 3-4 psi increase corresponds to the desired tire temperature. (measuring tire temperature is obviously more direct, although I don't know where you find out what Michelin, for example, says is proper tire operating temperature.)

In road use, the same approach applies... drive a twisty road where grip is important and measure tire pressure.

In this way, you're not relying on "feel" but rather a metric correlated to tire temperature (and grip).

Just a thought. I'm not tire expert, but wanted to toss in the idea of measuring pressure before/after.

Darrel

YYC53

The TPMS includes temp and pressure in my '20 E53. That alone provides a calibration point.

But you're certainly right, the reference temp of when the pressure was set and when the performance observation is made is the entire point.