jtalbert

ok, I am going to ask a stupid question. I have a a 4Matic and notice the front tires wearing on the outside as well. Since my car is a 4Matic should tires be rotated on a 4Matic as well?

Icebreaker

Actually my tires only lasts 16k with the Michelins, I have a 2005 C230. I have 80k on the car right now and I'm on my 4th set and will need to replace them soon again. Since they don't last long I've switched to Falkens which is really cheap and lasts longer. Since I don't drive agressively I don't noticed any handling issues.
The tire wear is due to an aligment term called "Camber roll". What happens is that Mercedes has a really high positive caster (9 degree positive) that when it turns the wheel will "lean" (inside wheel leaning out and outside wheel leaning in) and that'll cause the wear every time you make a turn but at the same time this geometry give great straight line stability.

Glyn M Ruck

Nah! the Benz system is such that when cornering the inside wheel leans on it's outer shoulder & the outside wheel leans in it's inside shoulder. Thus reducing wear on the outside wheel tyre shoulder when cornering.

Icebreaker

Isn't that what I said???.........

Glyn M Ruck

I did not read it that way. Maybe just a misunderstanding.

Anyway. Outer shoulder wear on a Benz front end is reduced by it's geometry. If alignment is correct outer shoulder wear is created by aggressive driving & dialled in understeer which is inherent in these cars.

EDIT. I only run Michelin PS2's ot Pilot Exalto PE2's on my cars. I've sold my C240 a year ago. I've never suffered shoulder wear.

Icebreaker

Yes I've used the Michelin Pilot, lasted me 16k, 2nd set lasted 15k, then I used Riken Raptor and it lasted 20k, I'm now on Kumho Ecsta at 72k and will be going in to my tire dealer. I think I'm going to go with a set of Falkens ZE-612 this time and see if I'll have better luck. Maybe my last set before moving on to the new E-Class, wonder if repair stats is better or worse than the C-Class?

hanknum

I agree that with a lot of caster, the inside tire will "lean" out from the car and the outside will lean into the car. But, the outside tire is the one that will be taking the bulk of the load due to the weight transfer...the one that is running on the inside of the tire.

ncmudbug

Glyn, does South Africa drive on the left like in England or on the right? Would that make a difference for us in the US where we drive on the right? Since, as you say, the caster affects the camber, would there be a camber adjustment if you staggered the caster as you recommend?

Glyn M Ruck

Same as the UK. Staggered castor does help with shoulder wear.

Glyn M Ruck

Yes~ the Michelin PS range are high grip superb handling tyres with soft compounding. They are not a long life tyre. You can't have it both ways. The New E Class has similar reliability to the W204 Class. Better than early W203 or W211.

Yes ~ I would have said lean in top or bottom of wheel but I think we all understand one another. Thus the outer wheel which takes max loading in a corner has it's outer shoulder somewhat protected by Benz geometry

ncmudbug

Thanks Glyn, but I wasn't clear.

Should the caster be increased on the LHS in the US to accommodate the difference in weight, road crown, etc.?

Should there be an associated camber adjustment if you alter the caster as you suggest?

Glyn M Ruck

NMB ~ Castor must be increased on the RHS on US cars or always passenger side wherever you are in the world. Camber should stay in spec.

ncmudbug

Thanks for the clarification, Glyn!

sammydragon3

just to add in my alignment guy did what u said glen where the caster was different and the steering felt too tight and didnt track striaght (when u let go of the wheel) and yes it was on a flat surface

i brought it to another guy and he put the caster the same and my car finally tracked striaght (when i let the wheel go)

make sure the toe is at .07 (toe in) camber is at -.07 caster is at 10

by far the best alignment i ever had

Glyn M Ruck

The one or (Max two) degree increase in castor on the passenger side of the car is to stop pulling with the camber of the road.

The bulletin is in the Wiki.

hanknum

Thanks Glyn. I'm still a little befuddled that I"m still getting the outside wear. The standard high caster should, as you say, "protect" the outer edge of the outside tire. The lowering of the car should induce more negative camber also. I guess as FrankW said, once they start to wear one way, they will continue to wear that way. I may have to just wait until I get some new rubber, or might try swapping the tires left to right (they're directional). What do you think?

Glyn M Ruck

Leave them where they are if they require specific rotation. It's understeer that messes with front tyres on Benz cars. Maybe you should put on a stiffer rear torsion bar which will reduce understeer. It's also tyre specific. The Michelin PS2 was really designed for Porsche. If you look at the tyre new it has a relieved outer shoulder which might be why I've never suffered shoulder wear. Porsche only run approx 5 degrees of castor so Benz is pretty extreme.

It is also driver aggravated. If you drive in a fashion that pushes the nose of the car you will kill front shoulders. If you flick the car into a corner to try & promote oversteer you will preserve front shoulders.

hanknum

Upon further investigation, the outer wear doesn't seem so bad now that the car has been lowered. I'll monitor once I get a new set of shoes and see.

Now to the rear...since I've lowered it, the inside of the rears are wearing pretty quickly (negative camber). I've looked at getting adjustable camber arms to reduce the neg camber. But, here's a pic of the rear left suspension, there are 3 "upper" arms. The top (middle curved one) appears to control the camber. If I change (lengthen) that one, it seems that the toe will also be affected due to the arm at 10 oclock. What do you guys think?

hanknum

Oops...here's the pic

Glyn M Ruck

Just get your camber correct & then readjust the rear toe to spec. Method is in the Wiki.

hanknum

Thanks Glyn. I searched, but could not find it...sorry, but would you happen to have the link?

Sounds like I can just get the adjustable camber arms and there will be some adjustment in toe in the OEM arms (w/o having to buy additional equipment), is that right?

Thanks again.

Henry

Glyn M Ruck

https://mbworld.org/wiki/images/3/3f...t_Rear_Toe.pdf