woody

I've noticed the edge blocks on my front tires, mostly on the outside, picking up towards the front. The car had this condition at 2700 miles when purchased used. I also noticed the same thing, maybe worse, on another 03 with about 2700 miles. The other car had Continentals, mine Pirellis. The dealer says "that's what they do". The car feels darty as if it has toe out. I'm afraid soon the tires will sound like knobbys. Hope someone can help.

vraa

Check your alignment.

It's not normal to cup. Check tire pressure as well.

woody

Thanks Ricky. The reason I think it goes beyond alignment as the car I mentioned had new tires and front and rear alignment 800 miles before I testdrove it. The tires were doing the same thing after only 800mi! The alignment Tech at Mercedes here said he had seen this condition many times with the cars in spec. I just have a hard time with that one.

vettdvr

I use the ride control in comfort mode. "no red led's illuminated"

I took the car to the MB dealer who told me all was right on the alignment.

I then went to an aftermarket shop that specialized in MB's. They told me there was a difference in how cars were
aligned for Germany vs. the US. Essentially the toe in was set for Germany for high speed loading to stress the front
end and reduce toe-in while driving. However in the US we can't attain those speeds (over 100 mph) legally. This results in normal
driving with too much toe-in. I also found that MB uses a preloader to simulate high speed loads to align the wheels. This is the procedure used in Germany. So when the dealer states that it is aligned,, it really is but to German highway speeds. Therefore we put the car on the alignment machine and confirmed that there was too much toe in for US driving. In order to correct the alignment I had to buy from Mercedes special suspension pins. (wonder why them make the special pins but don't tell anyone). The pins allowed the alignment with reduced toe-in. Since that time my tires are wearing normally. So the real issue is the speed you drive and the set up of the alignment. The local dealer wasn't very helpful in sorting this out, fortunately I found a MB specialty shop.

Changing to "sport ride" will affect the cupping. This will stiffen the ride which will prevent negative camber when hitting a bump. My guess is you still need to find a shop that will do the alignment. Caution though most will want to put too much toe-in, and or tell you they can't align without the special tool. The special tool is to preload to German highway specs. So don't use the tool. But if the shop is reluctant DON"T use them. Find someone who will work with you. My cost for wheel alignment after buying the 2 pins was over $350. So they do charge for their service and you will have to get technical about it. Hope this helps. Jim

MBTech21

If you search back through the archives, you should find the thread where we discussed the actual readings you should have (not the spec)- I think it was on vettdvr's car, right?

vettdvr

The biggest difference is the toe in set at 0.05 for a total toe of 0.1 degrees.

Jim

sosh

Cupping is most always caused by underinflation.

bltserv

Maybe its just the tire brands.

My 2005 SL55 had 22K when i got her. Had the Pirelli`s. Sounded like a
knobby tire under 15MPH. Sounded like bad wheel bearing.
Dealer said the Pirelli`s just wore like that on a SL and worse
on a heavier SL55.

Put new Michelin`s and got it checked for alignment.
Like butter now. Really nice. If I get 15K miles I will be happy.

Had the same issue with the Conti`s on my CL500
If you did not rotate very 2500. They cupped. And you really
noticed it on the rears. A bit of wheel hop at certain speeds and pavement types. After 2 sets of Conti`s. Went to Michelin on the CL500
Much better wear. And rotating every 4000 or so.