Uneven tyre wear - advice please

[DaveA]

Hi guys, some advice required please.

Recently had a 'B' service on our 208 CLk Cab. and they picked up that the front tyres were wearing unevenly - almost bald on the outer shoulders. The recommedation was to get the geometry checked when the tyres were replaced. With the state of the roads, and the fact that my wife had hit a fairly large pot-hole while in Ireland recently causing the rear head rests to shoot up, I didn't think this was un-reasonable! Did a few more miles while I worried about this and then decided to replace the front tyres and get the geometry checked/fixed at the stealers.

Well, the car was booked in today at Canary Wharf - quoted up to £260 to check and adjust the geometry and £200 for the tyres - all plus the dreaded VAT!

My wife picked up the car this evening and they told her that everything was within Mercedes specifications and no adjustments were made. The charge for the tyres was as expected but they only (only!) charged £105 for the geometry check. They suggested that the uneven tyre wear was caused by incorrect tyre pressures.

Now I check the tyre pressures every time I wash the car (not as often as I should but fairly regularly!) and they have never needed much adjustment, up or down. Does this sound reasonable, bearing in mind most of the wear was on the outside shoulder of the tyres and worse on the passenger side?

I have attached a jpg of the geometry print out. Could someone more knowledgeable about these things give it the once over and let me know if there is a problem?

Many thanks
DaveA

 

[DITTRICH]

...I seem to remember reading in another thread that **in general** mercs wear the outer shoulders of the fronts and the centres of the rears. This was certainly the case with my W202 C230k saloon . However, this was connected with the speed at which I was going around corners - or so the dealer told me. So, if like me, you have been going fast enough to **drift** slightly around corners then this could be just normal wear! Don't know about the data though - sorry.
Rgds
Les

 

[stwat]

If tyres are under inflated they will wear on the outer edges. If they are over inflated they will wear more in the centre of the tyre.

Stu

 

[Will]

If tyres are under inflated they will wear on the outer edges. If they are over inflated they will wear more in the centre of the tyre.

Stu

True - in general.

But on RWD cars (like most MBs) the steering action on the front will exacerbate this wear on the outer edges, and the centrifugal forces placed on the rear wheels as they 'spin up' will again cause more wear to occur in the centers than on the outer edges.

If you are lucky enough to have the same size wheels/tyres all round you can rotate your wheels to even the wear out more.

Will

 

[andy_k]

If I'm reading the data right (a bit of a drastic assumption i know ) i would say both front wheels are out of tolerance.

The front right camber (with toe) is out of the target range as is the front left castor by way of steering lock and the front left toe in (pressed) is right on the limit.

If I were you I'd try and run those figures past another dealers service manager and see if they see it as a problem

Andy

 

[LazyBob]

Here's a link to some geometry info. http://www.tirerack.com/tires/tiretech/general/align.jsp
General link to some witty tyre/suspension info http://www.chris-longhurst.com/carbibles/index.html

I find that the outside of the nearside front on my W140 does wear quicker than any part of any other tyre. moving them to the back before too much wear sets in evens them out again.

How worn were they? What was the tread depth(s) across the tyre?

 

[MARVYG]

Hi, I had exactly the same with my CLK 230k W208, Took mine into my local HI-Q Garage where they adjusted it out, been fine ever since. And it only cost £30!

 

[Robbo]

I find that the outside of the nearside front on my W140 does wear quicker than any part of any other tyre

Same on my W203. I attribute it to doing most of my driving around Bracknell which means I am constantly going around roundabouts. I over-inflate the front tyres by about 4psi and this seems to help a lot.

 

[Dieselman]

The wear is probably due to too much use of the power steering. Turn the wheels when not moving and it kills the edges of the front tyres.

If you think it's not down to you then watch the wife park the car. For some reason most women appear to be able to make the car either move or turn the steering, but not together. Why is that?? (tin hat well and truly on)

The geometary printout is Ok but there is a setting out of tollerance. The front left castor is set back a bit. It's only 6' or 1/10th degree which is very slight.
In reality this won't be a problem but may cause the car to steer slightly to the left as the self centering of the steering will be different either side.

 

[DaveA]

Thanks for all the comments, you've helped to put my mind at rest.

I can't check the old front tyres anymore, the dealer disposed of them when the new ones were fitted. The car drives well enough but I had noticed a very slight pulling to the left. I thought it was probably due to the camber of the road. Next time I'm on the motorway I'll see how bad it is, it is very, very slight.

My wife drives the car much more than I do and I can see exactly what Dieselman suggests! I cringe everytime I see her manoeuver (sp?) the car. Those front tyres really take a battering!

At some point I may swap the fronts with the rears to try and even things out. So thanks once again. I'll keep a close eye on the tyre pressures and how the new tyres are wearing.
Dave

 

[Dieselman]

My wife drives the car much more than I do and I can see exactly what Dieselman suggests! I cringe everytime I see her manoeuver (sp?) the car. Those front tyres really take a battering!

Change the auxillary drive belt for a shorter on missing out the power steering pump. Wifey will soon get the idea of the problem,..oh and HUGE triceps.