All,

My 2010 ML just went over 43,000 miles (1st owner) and has uneven tire wear on the front right wheel. FYI, all four wheels were replaced around 20,000 miles. The outer edge of the road contact portion of the tire was wearing really fast, near bald. The front left wheel is wearing in the outer edge as well, but at a much slower and more acceptable rate! The rest of the tread on both tires are in excellent shape!

I rotated the rear wheels (excellent tread life left and even wear across the tread) to the front and took the car in for an alignment (2-weeks ago).

The alignment showed no major issues I can discern:

Specs (Front Wheels)
Target Camber: FL -56' +/-30 FR -52' +/-30
Target Caster: FL +5"40' +/-30 FR +5"55' +/-30
Target Toe: FL +7' +/-4 FR +8' +/- 4

Before
Camber: FL -46' FR -58'
Caster: FL +5"28' FR +5"24'
Toe: FL +11' FR +16'
Total Toe: 28'
Front Axle Setback: -1'

After
Camber: FL -42' FR -58'
Caster: FL +5"37' FR +5"34'
Toe: FL +8 ' FR +8'
Total Toe: 16'
Font Axel Setback: -4'

After 200 miles on the "new" tires and an alignment, wear on the front-right wheel is very noticeable - though not on the outer edge at this time; wear is not noticeable on the front-left. Moreover, negative camber should cause more wear on the inside than outside (assuming toe is off). And if it matters, the car gradually and then increases its pull to the right.

Since the wear is focused only on the outside, can I rule out wheel bearings and bushings and focus on struts and springs?

Your expert opinion is greatly appreciated.

 

Update: Took the car back to MB to re-check the alignment since the car pulls to the right when accelerating from a stand-still.

Their final "diagnosis" and "analysis" is very frustrating since the alignment is within specs, the tires are properly balanced, and there is no suspension issues. Their position is since left-rear wheel has less tread left than the other three wheels, it's causing the car to pull to the right!! And until new tires are fitted at all 4-corners, there's nothing else they can do.

I reiterated the wear pattern (to the front-right wheel) is identical to the wear prior to the alignment and wheel rotation. I hope they're correct, but at this point, it appears they're punting the issue until the car is out of warranty before looking to see if the steering mechanism or wheel bearings are faulty.

I guess we'll have to wait and see

 

Just curious if you park in a garage or parking lot with tight corners? I had an issue when I used to park in a garage with those corkscrew ramps. It constantly beat the crap out of my right front tire on my EClass.

 

Thanks for the reply.

I thought about that too, but when the missus allows me to take the ML, I take the same amount of left turns (leaving) as right turns (arriving) at the office garage (non-corkscrew ramps).

The ML is primarily driven by the missus to work and her path to work/home is near-highway speed conditions and she parks in an open parking lot.

I even thought it was our driveway since it can be a tight squeeze on our street, but we only make left turns to enter the driveway; backing out is a cinch - straight back.

Still scratching my head, but I guess we'll find out in about 2x,xxx miles after new tires are put on.

 

Do you have a good Indy mechanic, not necessary MB specific? I would check the front control arm bushings, there might be enough play to cause the wear, but wouldnt have showed up in the alignment. BTW, left turns are what would put the most wear on the outside of right front tire. I think you meant to say you only make right turns from street into your driveway.

 

No, I make a left turn into my driveway. I can understand how a left turn can put pressure on the outside of the right wheels, but, it's a 2-mph left turn.

I've thought about the CA bushings and had hoped the dealership would have looked at the suspension system, but I don't think it happened in this case - they appeared only focused on just the alignment and the wheels.

The SA stated if they don't find anything wrong with the alignment and wheels, then it would probably be a suspension issue. When the SA informed me their assessment was that "it was due to uneven tire wear", he wouldn't acknowledge the wear pattern was the same after the wheel rotation and alignment.

I'll keep an eye on the wear pattern for the next few hundred/thousand miles. If the wear still occurs, I'll look into the CA bushings and tie-rods. Hopefully this forum has a few DIYs on how to remove/replace them.

Thanks for perspective.

 

".....I'll keep an eye on the wear pattern for the next few hundred/thousand miles. If the wear still occurs, I'll look into the CA bushings and tie-rods. Hopefully this forum has a few DIYs on how to remove/replace them."

K-MAC manufacture Front Camber and Caster kits and Rear Camber and Toe adjuster kits to properly compensate for premature edge tire wear and improve traction. Currently front and rear Toe only adjustment is available OEM on virtually all Mercedes models.

 

Update to my issue:

Took the ML to my Indy mechanic and had all 4-tires replaced, balanced, and an alignment done.

The mechanic checked the bushings and bearings, but did not notice any unusual wear or tear.

As for the alignment, it was WAY off. When the alignment was completed and re-checked by the MB Dealership, the ML still pulled to the right. According to the Indy Mechanic's alignment machine, at the specs set by the dealership, it's going to pull to the right. An alignment was done, and now the ML drives straight as an arrow!

The new tires were Continental Extreme Contact DWS 255/50 R19. Interestingly, only 3 of 4 wheels required wheel weights... I'm taking the ML back to the Indy shop this Friday to have the 4th wheel (front right) checked since the ML vibrates at 65+ mph. However, the vibration only occurs on certain lanes/roads at that speed (for example, it'll vibrate in the #1 freeway lane, but not #2 lane)!

Hopefully the new alignment will save the tires from premature wear, but we'll have to wait and see.

 

Thanks for update. I have found these suspensions are very finicky when it comes to tire balance.

 

A final update:

The wheel mount and balance wasn't very good at the indy shop. After a few failed attempts by them to fix the vibration, I took the ML to a wheel-shop for a road-force balance, which fixed the vibration issue. The rear wheels were each off by 3oz!