Antony15828

I have a serious problem. My mom just recently got an used 2011 gl550 and the tire rims (the AMG ones) are breaking basically every week, resulting in the tires leaking air. We have Pirelli r21 wheels, and we are desperate. What is the correct tire pressure for these wheels? We cannot afford having to repair these rims every week!

BlownV8

What do you mean by tire rings?

Antony15828

Tire Rims. Sorry

DennisG01

The rims are breaking? One would think that after 4 weeks (and four new rims), the problem would be solved?

What exactly do you mean by "breaking" Do you mean the "bead" is breaking? Meaning the tire is coming unseated from the rim? Hitting a lot of potholes? Corrosion on the rim? Since you (you're mom) just recently bought it, I would first take it up with the place you bought it from.

Follow the tire pressure label on the inside of the driver's door jamb.

FYI, you have Pirelli r21 TIRES, not wheels. Wheels are the metal things.

BlownV8

Are they chromed? Are the rims cracking from potholes? 45 PSI should help protect the rims.

Antony15828

Dude.. so sorry haha.. english is not my first language and I was in a hurre then. We are getting what appears to be little cracks on the inside part of the wheels. These appear at least once a month. We had already fixed them at least four times.

I live in a country were the roads are not in the best condition, but they are not that terrible. These wheels are supposed to be strong.. We never had these problems with our previous cars.

Antony15828

Isn't 45 psi a little too much..? I don't know dude..

BlownV8

I run at least that in my 22's and have never had issues with bent or cracked rims. If you have bad roads, you need the extra pressure to keep the impact from the potholes away from your rims.

Antony15828

You got a gl too? Sigh... Still a little uncertain but I'll try anything that could work

DennisG01

No worries

Can you post a picture of what's happening? Yes, definitely check the pressure to make sure you have enough in there. As the wheel/rim size (diameter) increases, the aspect ratio of the tire (the size of the sidewall) goes down and you end up with less "margin for error" of your tire pressure. On top of that, the outside edge of the rim is effectively closer to the ground and more likely to strike the inside edge of a pothole, too.

alx

you got stress fractures. those wheels were beaten to death in their previous lifetime and now (probably in a new climate) the fatigued metal is expanding/ contracting and is cracking.

my feeling is that you will end up ditching those wheels altogether. btw, i wouldn't be surprised if those are some cheap replicas.

also make sure your tires are xl- rated and inflated to 40-42 psi when cold.

EWT

I've cracked two on my 550 and never bent/cracked a wheel in my life prior to the GL. They're not very strong. They crack where the spoke joins the rim which causes a slow leak. The price on a used wheel doubled from wheel #1 to #2, and there weren't many available the last time it happened (couple of years ago).