jaramd

On my EQS SUV 580, I just noticed that all of the tires are at 41 psi (from the dealer). And the recommended tire pressures on driver door pillar is Front 47, Rear 43. FYI, the tires are Scorpion Zero, All Season, 275/45 R21.

I called the EQ Premier Line and my local dealer to confirm the recommended pressures; neither gave me any feeling of confidence that they knew when they both said to refer to the "inside door of the gasoline flap".

I am wondering about ride quality and tire wear if I increase to the recommended pressures.

Please let me know of your experience and the pressures that you use.

Thanks in advance.

hlothery

My door has two stickers. One is for the maximum recommended pressures for a heavy load (can't remember exactly, but 47/43 psi, or something). The other is for everyday use with normal loads, and recommends 41 psi all around. I follow that one, and try to keep my tires inflated to 41 psi. Ride quality is great, and I have over 21K on my tires with lots of tread left (Goodyear F1 Asymmetric 5).

jaramd

When I first looked at the tire pressure label, I only saw the colored one (see first photo).. I just didn't see the black and white second label above that details both normal and max load (see second photo).... and no one at the Mercedes 800 line or the dealer made reference to either the second label or the normal vs max load values...

Thanks so much for your guiding response...!!

jadatis

Best is to determine needed tirepressure from start.
The carmakers determines recomended pressures using GAWR's and max technical carspeed. But nowadays often higher then calculated for reasons of energy saving, especially electric cars.
Now 98% normal use, with 2 persons and a little load, axleloads lower then GAWR's, and not max tech carspeed used of mayby 150 mph /240kmph.

So if you are able to determine the axleloads in your use 99% acurate, the most tricky part, and your responcibility, you can look back in my made list for your loadindex 110 XL/reinforced/extraload tire. Maxload 1060 kg/ 2337 lbs AT 42 psi upto 160kmph/99mph.

Made my list for axleload and maximum reserve with still acceptable comfort and gripp.
For that I gave 90% of calculated axleload for reference-speed of 99mph. Determined this to give a deflection, that gives still acceptable comfort and gripp. Then no pre or after-calculations needed, like deviding by 2 or adding a reserve in load in front, or pressure afterward.
That easy, that it gets dull.

You could also look back GAWR's in my list, to see if they recomended that extra high pressures, for energysaving.

Here it is, in front of cold psi axleload in kg and behind in lbs.
Axleload/cold psi/ Axleload
984 kg/ 20 psi / 2170 lbs
1027 kg/ 21 psi / 2264 lbs
1069 kg/ 22 psi / 2358 lbs
1112 kg/ 23 psi / 2452 lbs
1154 kg/ 24 psi / 2546 lbs
1197 kg/ 25 psi / 2639 lbs
1239 kg/ 26 psi / 2733 lbs
1281 kg/ 27 psi / 2826 lbs
1324 kg/ 28 psi / 2919 lbs
1366 kg/ 29 psi / 3012 lbs
1408 kg/ 30 psi / 3105 lbs
1450 kg/ 31 psi / 3197 lbs
1492 kg/ 32 psi / 3289 lbs
1534 kg/ 33 psi / 3382 lbs
1575 kg/ 34 psi / 3474 lbs
1617 kg/ 35 psi / 3566 lbs
1659 kg/ 36 psi / 3658 lbs
1700 kg/ 37 psi / 3749 lbs
1742 kg/ 38 psi / 3841 lbs
1783 kg/ 39 psi / 3932 lbs
1825 kg/ 40 psi / 4024 lbs
1866 kg/ 41 psi / 4115 lbs
1908 kg/ 42 psi / 4206 lbs/ reference-pressure
1949 kg/ 43 psi / 4297 lbs
1990 kg/ 44 psi / 4388 lbs
2031 kg/ 45 psi / 4479 lbs
2072 kg/ 46 psi / 4570 lbs
2113 kg/ 47 psi / 4660 lbs
2155 kg/ 48 psi / 4751 lbs
2196 kg/ 49 psi / 4841 lbs
2236 kg/ 50 psi / 4931 lbs
2277 kg/ 51 psi / 5022 lbs/maxcold often given on sidewall

c4004matic

With air suspension, the optimal pressure is the highest one. It offers the best handling, braking, range, AND comfort. It seems conterintutive but a firmer tire allows the best dampening profile from an air suspesion. It also protects your rims in pot holes. The only drawback is harsher impacts on very broken pavement. On any other situation a firmer tire is better, particularly with an air suspension. With steel springs higher pressures make the ride more nervous.

QuadBenz

Hmmm… I may have to test this theory

QuadBenz

Also, if MB recommends 41 psi all around for normal load & 47F 43R for max load, which do you recommend? 47 and 43?

c4004matic

Again, I always use the highest allowable pressure. This is my 4th MB air suspension vehicle, and in all, the highest pressure has always been the best setting. The only negative has been slightly harsher impacts in very jagged broken pavement. But unlike many others owners, I have never bent a rim even after hitting road craters in Chicago. I also don't have to worry about supralegal speeds.

QuadBenz

I dunno... I tried it out and went for a drive. I'm getting better efficiency but overall I'm not sure that my takeaway was more comfort. I think it's slightly less comfortable, especially being on run-flats. It was a firmer experience and I felt more road texture than I usually do at 41 all around. And yes larger bumps were definitely a little harsher.

I'd love it if others could weigh in on this as well. The more thoughts the merrier

QuadBenz

I went down to 43 all around and the improvement to ride comfort is appreciable. I’ll try this out for a bit

jadatis

Read my post #4, and try to dermine the data for it. Mayby even 30 psi is still safe for the tires upto 160kmph/99mph (or do you use higher speeds) and then comfort and gripp much better and no nervous steering.
The more energy-consumption is a choice for you to make then, but still will be acceptable.
List is only for XL tire with loadindex 110.
​​​​​​EDIT:
Googled the EQS SUV 580, and found 7seater of gvwr 3375 kg/?? Lbs, for wich gawr's must be about 1700 kg, wich would need about 37 psi, a bit higher then I expected, but still for fully loaded completely safe upto 160kmph/99 mph.
The specifications gave max speed of 210 kmph/ 130mph.