I posted this in the Tirerack section, but am repeating here.

The only advice other than alignment was "Check your ball joints and thrust arm bushings."

Any other thoughts? These have about 12K on them. The rears of course are near ready for replacement. I would really like to go 2x the distance on the fronts. This is the second set wearing like this.

 

what's your toe?

 

It looks like a camber issue. If you know for certain that the alignment is spot on then I'd start looking at ball joints or control arm bushings. But normally you'd feel those issues in the steering while driving. Does the car feel okay? What's the mileage? Ball joint replacement seems common with this chassis at higher mileage (around 60-70k)

 

Camber and under-inflation, same as mine I run 36 psi and still get the shoulder wear like yours plus a little scallop on the inside too.
Next set of tires I plan to add all the camber I can (crash bolts) and run 38 psi.

 

Concur, if you are not lowered toe is the greater indicator of wear because it involves "scrubbing" or "dragging" of the tire.

I run -2.50 camber in my W212 but the toe is the most important setting in regards to wear IMHO. My toe is set to spec and my tires are actually wearing quite evenly.

 

if that's the passenger rear tire, I was told they all do that. Or at least it's very common. Mine's the same, alignment is dead on. I found that running 30psi in the tires got rid of the odd wear. my local oil change place was putting 40-45 psi in them.

 

My fronts are wearing exactly the same as yours. My E63 has 22K on the odo, and I know that my suspension parts are good.

It is negative camber. My passenger side wears a little worse than the driver side, it is at "the edge" of negative camber spec....it came from the factory that way, and my car tracks/handles perfectly.

My dealer installed a camber bolt last year to reduce r/f camber, problem was that this also impacted caster, causing a right pull, the car cornered notably worse going left, and it just felt off kilter when going straight.

I had the camber bolt removed, got things re-aligned, and the car again tracks/corners perfectly. Inner tire wear returned as before, although it gets less as the tires learn to wear with the camber settings.

My front toe is set at .08 positive per side which I have found to optimal. I also reduced tire pressure to 37 PSI cold in the fronts, which may also help.

I have concluded we are banished to replacing the front tires every 20K...maybe a little less.

 

^^ What he said. I had this on several sets of tires till my toe was corrected (thanks tbone). Shop was also aligning according to steel springs as opposed to airmatic. Get crash bolts to get camber corrected a bit and pay a lot of attention to toe.

 

OK guys, thanks. I will try to get the alignment readings scanned in soon.

I will say that after this alignment the car handled like a dream. I do not feel anything unusual in the steering and a buddy I let drive the car at Thunderhill did not notice anything. I do have 70K on it now, but this has been a problem since 50k.

As for tire pressure, I discussed the odd wear with the shop that aligned it and they recommended higher pressure as well. I now run 42-44 PSI.

More later tonight.

 

One more thing, might not be important but most alignment shops i have been to in the past would raise the car to get it on the lift but forget to lower it before taking the readings/aligning so check that they lower it first.

 

higher tire pressure is what caused my tires to wear out like that.

 

If you are running stock wheels, 42-44 cold psi is too high. You will get wear in the center of your tires. The door jam and/or gas cap will tell you the optimal tire pressures for your car. The tire itself will list a max psi but it doesnt know what car its going on or what width wheel and thats a max psi not an optimal psi.

 

improper toe will kill your tires WAY faster than moderately negative camber. I've been driving with negative camber and zero toe with *almost* even tire wear for 15 yrs now.

 

I agree with you 100% as your og post and mine stated... People always think camber is the big treadwear killer. A tire that is off 2.50 degrees (camberwise) but not dragging or scrubbing will last much longer than if the toe is out. Camber is often the chosen reason because its visually apparent unlike toe.

 

Right, the geometry/alignment begins with (rear) toe being correct. Agree with camber comments also, thanks.

Refreshing that another member recognizes that! That is why you are a moderator, no doubt.

 

yup, it's too bad that on many forums, camber is the blame. Good news is toe is very easy and cheap to adjust.

 

36PSI normal driving
49PSI for sustained speeds in excess of 100MPH.

Leave me a little leaway.

Prior I had been running 40PSI and the wear was even.

I have been busy and have not gotten round to finding the paperwork.

As for the alignment being done properly, they even put 200lb in the front seat to ensure the car was loaded correctly. STAR leveling and all that was checked.

 

Then what is "correct toe" according to MB? If you set toe neutral then that will effect the car (depending on chassis on what you want the car to do) a certain way. I guess what I'm trying to say is sometimes you want slight toe out or toe in, and not neutral (all depending on handling characteristics.) I run toe out (very, very slight) on my 933 because it handles better that way and has sharper turn-in. Plus I have stiff polyurethane bushings which the MB doesn't have as a softer street car. But even then I don't seem to get scrubbing wear on the inside edges like that (?) Is it because of the weight of the car (in comparison to the E Class?)

Toe is a trade-off in steering/handling characteristics and tear wear and so what does MB say? Are the specs for neutral toe (with whatever the camber is supposed to be) or are you guys running neutral toe because your running an out-of-spec camber?

I'm guessing MB specs are a slight toe in so that the car runs straight on the freeway without constant steering input by the driver, etc.. Which is why there normally seems to be more outside edge scrubbing on these cars.

I guess what I'm trying to figure out is that does MB say neutral toe? I realize totally neutral obviously should mean no tire scrubbing but what does it do to the steering and handling characteristics?

I've tried asking at the dealership but never got a real answer.

Thanks.

edit: btw, I remember Darin at West Side Alignment (he preps a lot of track cars and corner balanced my P-car) saying that improper toe causes a wavy or feathering pattern inside or out (depending on toe in or out) and not a smooth wear. Those pics from the OP show a smooth inside wear which would mean camber (?)

Or maybe it is wavy and the pics don't show that.... ?

 

I run zero toe strictly for tire wear purposes as u stated. My car is just a cruiser (daily driver) for me

 

49 PSI for speeds over 100 Where did you find that information?

And if thats cold, because the 36psi is cold, what do you think you really are running at those speeds??? 54psi?? Thats scary high psi.

 

Vic,
what tire pressure would you run on 20's on an E55 (cold)?

I usually set mine around 38.

 

38psi is a good number--- depends on your profile too.

My GTR has runflats (255x40 and 285x35) and 20's so the PSI is 29!! OEM recommendation since I have stock tires.

On my Benz I run 38-39 with 255x30 and 295x25.

 

I seem to recall some discussion concerning excessive front tire wear on the inner portion being attributed to driving the vehicle in the lowest suspension setting. When I purchased my E55 the inside portion of the front tires was severely worn compared to the rest of the tread. I purchased new front tires and took the car to an old school alignment shop, the mechanic checked the alignment on all of the height settings and told me that on the lowest setting the tires have a slight inclination to inward camber and if I drove around on this setting I could expect to prematurely wear the inner portion of the tire.

 

You got 12K out of the rears???? I get like 6 maybe, Im slammed..RTLM 0 Front 3 rear. and I uses Falkens

 

Here you all go. Looks like positive toe is the spec. Of course it could be that a 2007 should be a different spec. You guys know the differences better than I. Never noticed that caster number was out when they finished.

REMEMBER, the tires in the front were worn to the cords on that inside edge when I brought it in. So think about that when comparing before and after.