cbanka

I have a 2008 C300 4matic and the inside of the rear tires are cupping. The dealer said it happens with this model and just buy new tires. I find this unacceptable. Cupping occurs when the tire leaves the ground typically during breaking. Often cupping is a result of a bad suspension. Has anyone had this cupping issue fixed? I know I will need to buy new tires, but I want to fix the problem first.
Thanks!

noka

Alignment perhaps?

kowyzg0moo

Definitely alignment issues - that means the sidewall of your car is being rubbed against the tire constantly. u should be able to hear that! get that fixed asap.

noka

Sidewall of the car? I think maybe just alignment (caster/camber angles). Unless maybe something wrong with suspension on both sides.

cbanka

I think alignment is only half the issue. If it was just alignment, I would have wear only. Since cupping is occurring, I am thinking shock in addition to alignment. The car makes a slight rumbling when going down the road which is from the cupped tires. There is no contact between the tire and the physical car (is that what you meant kowyzg0moo?). The car is a 2008 C300 4-matic with about 38,000 miles. Have any of you with this car looked to see if you are having the same issue? Thanks for the replies!

noka

Could be. A quick Google search listed both as possible causes, among others.

Carsy

I have the same issue at 38,000 Km. On smooth tar the car sounds like an out of tune orchestra . My tyres are French made Bridgestone Turanzas. I am looking forward to changing them out when worn out to Michelin Primacy HP as suggested by Glyn.

I think that the car is prone to this issue because of the suspension design & settings. I have had no problems with my Peugeots in the past.

I also think that by rotating the tyres correctly during their life will minimise the cupping & noise.

Good luck.

noka

The "Sport" has staggered width tires (at least in the US).

Glyn M Ruck

Increase rear toe.

Carsy

Hello Glyn,

Excuse my ignorance but how do I go about adjusting the rear wheel toe in ?

Thanks,

JC

cbanka

Wouldn't I need to adjust my rear camber (currently too negative) and not toe? Or will the toe make a difference? I would also like to know how it is adjusted. I was told once by a mechanic that he could not change the alignment of my rear wheels. I responded by asking why he then charged me for a "4 wheel alignment"

JimPap

What did he say?

Is this something that only the MB dealer could adjust due to special tools?

cbanka

sorry for the possible confusion, I was talking about when I took my camaro to get aligned, not the mercedes.

Glyn M Ruck

JC - just hang in there - I don't have my WIS loaded at present. Computer rebuild underway. My alignment shop has it's own trick like they do for the front by setting castor one degree more positive on the passenger side of the car than the drivers side to stop it pulling with the camber of the road. Typically 10.6 & 9.6

I know Benz has different thickness washers to get the diff nose angle correct. They show no shims in the EPC but I'm fairly sure that my alignment shop shims it from memory.

Let me get one of our 203 guys to pull up the MB recommended method of toe correction. Will revert. Good refresher for me. I should know this but don't. A friend had it sorted on his AMG. There is no camber adjustment without going for an aftermarket camber arm. They exist for the 203 - not sure about the 204.

Excuse my ignorance

noka

Wouldn't too much negative camber cause inside edge wear without cupping? My guess is that a toe-in problem could cause cupping. I'm no alignment expert and could be wrong.

Glyn M Ruck

Cupping is very tyre dependent & how the tread blocks deform with different alignment. Benz requires toe-in on the rear. Our 203 & 204 have rear toe set at max spec & both cars wear their PS2's perfectly on the rear.

Glyn M Ruck

JC & others - Toe adjustment kindly provided by johnand from the 203 forum.

They use cam bolts, same as W203 although the set up is slightly different - now we know. Older models used shims.

Thanks John

EDIT - just to link the two threads.

https://mbworld.org/forums/c-class-w...djustment.html

Carsy

Glyn,

Many thanks. Great info that has been printed & filed away !!

JC

Glyn M Ruck

John - we are all a bunch of talented amateurs at best that help one another. What staggers me is the number of shops including dealers that tell customers that there is no adjustment & it's their professed area of competence

cbanka

Update. I took the car in prepared with what I learned here and with Glyns .pdf (many thanks). I told the service tech I had wear, he reached under and said that I had cupping as well and that he recommends realignment. Side note, the other dealership said they could NOT do anything with it which is why I started this post. Anyway, Mercedes will not cover an alignment after 1 year or 12,000 miles. So, I am going to get new tires, pay for a alignment and be on my merry way. Thanks again for all the help!

Glyn M Ruck

Wish you well sorting out the problem. The car should not destroy tyres like that.

boom132

I am having the exact same issue with my 2010 C300 4Matic... Conti DWS destroyed within 10 months with less than 20K miles on them... yes, I know they are staggered, and wear differently with the fronts (which show very little wear), but geez... these shoes are not cheap.


Thank you Glynn for providing the toe-in procedure... I will be taking this to the dealer for review and alignment...

JPc300

This does not look like cupping. From what I can see from the picture it looks like a combination of negative camber (needs alignment) and a one time slam on the brakes could possibly explain that section with more wear.. lol! (I'm serious though) check all 4 tires for similar wear. Another possibility would be worn out/broken chassis part which would cause an alignment issue. Most of the time my experience with Mercedes and BMW, from factory , they come with a neg camber already. But as the control arm bushing and other suspension bushings sag/wear, they camber in more and more. (FYI this is why camber kits are used. They make the proper corrections necessary to correct camber with out needing to replace costly suspension and steering parts) Hope this sheds some light.

Can you post more pictures of the tires in question? I would like to see the other side not shown in the picture for a ID.

hhbenz2014

I have a 2014 C300 Benz and I had to replace three tires already in 14 months of driving, I have never had so many issues with tires and wonder if there are other people having similar issues, the tires seem to get bubbles very easy. Any normal holes that other tires would manage normally create bubbles on this car tires. If anyone has replaced the original equipment with tires that are performing better please let me know

Thank you
Oscar

black lavender

Funny this thread was bumped.

When I purchased my 2008 C300, it came with cupped tires. I thought something was wrong with the engine. Took it to the dealership, they said it was because of not using premium gas. Said they took care of it, still made noise.

Bought aftermarket wheels and tires, and poof, the sound was gone. Took the wheels to a tire shop, said the tires were badly cupped.

They "looked" brand new though