2012MLBlue

There is a discrepancy on what tire pressures I should be running with these 20" AMG rims and Continental Cross Contact LX Sport tires. The inside of the fuel filler lid says 35 psi regular, 41 psi for max load. The 2 labels inside the drivers door both say 45 front, 48 rear. It does NOT say max pressure anywhere on those two labels.

Thoughts?

Right now I am running 41 front, 43 rear but don't want to prematurely wear out these very expensive tires.

venchka

A legible photo of the label on the fuel filler door might help us shed light on the question. My huntch: the lower number is light load. The high number is max load. That is the way all of my cars since 1999 have been labeled.

Wayne

2012MLBlue

As stated previously, the fuel filler door conflicts with the labels inside the drivers door. I will post some pictures later.

jadatis

If you have 20 inch rimms, you probably have low aspect ratio tires, example 255/35 R 20. The 35 stands for hight is 35% of the wide of the tire.
For those tires you have to keep high pressures to make shure your sidewalls dont deflect ,and by that dont bend, to much, and so wont get damaged by driving at speed. Thoug the pressure at wich the maximum load may be carried for normal car tires/P-tires/SL load is 35psi for american tires, and for Extraload/XL/Reinforced 42 psi , I have my doubts if the maximum load is calculated right for those tires by the tire-makers.
So for savety you have to add mayby even 25% to that pressure.
Did not totally work that out, but there are about 4,5 reason that I think the calculation of the tire-makers comes to to high maximum load, and so to much deflection of the tire.

For your tires this means, that you have to keep the high pressures, though it is bad for comfort and gripp, but a blewing tire gives more damage.
Also for longer tire live, what you want, it is important.
Not for the treath but for the sidewalls. Because the treath stays over a large range of pressure with its total wide on the ground, centre wear wont happen that fast. But if your sidewalls get damaged you can trow the tires away verry soon.

venchka

ps: Also include tire size. Pressure varies all over the map based on tire size vehicle weight. I'm running 20" tires on my GLK. Normal pressure is 33 all around. Loaded is 35 front/39 rear.

The door pillar numbers came from the USGummermint. Treat the information accordingly. M-B placed the fuel door label based on the tire+wheel combination on the car/truck when it was built. If that combination has been changed, the label doesn't apply.

Wayne

GregW / Oregon

Fuel filler door is correct, no doubt. Over 40 is extremely high. Lower it to 35 and see how much better it feels. Maximum pressure is on the tire sidewall, but don't use that as a guide.

jon2002

2011 w164 ML550 here with the oem AMG 20s...265/45-20s, here's my advice.

Use a tire depth and tire pressure gauge and keep a close eye on the tread wear. From my experiance, the vehicle wears the outsides of the tires alot more than the centers from using the light load recommendation at 32-35psi even though my wife and I are the only ones in the car.

This car is heavy and seems to require a lot more than 35psi to wear the tires evenly across.

41f/43r is probably good if you can handle the harsh ride.