Tyres "scrubbing" on inside wall/edge

[Jason Carson]

Hi,

This is my mum's Mercedes C-Class Couple AMG Sport she's had the car from new and tyres which are shown in the pictures have done 22,000 miles. Yesterday she had a service and Mercedes called to say about some wear on the inside of the front tyres which I thought would be something to do with camber / alignment or something but when I looked at the tyres it must be something else. Mercedes says they've never seen tyres wear like this before, they asked if we have planks or anything in the centre of the floor of our garage (which we don't) apart from that they have no idea what's caused it. They returned the car and left it at that.. The car is only 18 months old and I feel this needs to be looked into further but as the tyres are seen as a wearable part and not usually under warranty would I just be wasting my breath?

The tyre are Continentals and are still the original tyres fitted from now all apart from one at the rear which was punctured 6 months ago.

Only the front tyres have done this, the rears are fine.

We live down some bumpy back roads which have quite a high raise in the centre in some areas we have to drive on the side a bit just to stop our cars bottoming out which may have something to do with it. But wouldn't this then do the same to rears and all of our other cars too? My A4 has a similar width on the chassis but has no sign of any kind of wear related to the Merc.

Photo 21-02-2013 10 53 30 AM.jpg

Photo 21-02-2013 10 53 37 AM.jpg

Photo 21-02-2013 10 54 00 AM.jpg
Here you can see the groove digging into the tyre.

Photo 21-02-2013 10 54 13 AM.jpg
The outside of the tyre is fine.

Photo 21-02-2013 10 54 22 AM.jpg

[Autobulbs]

To be honest mate 22k miles out of the front tyres is damn good.... The fact the insides are a bit more worn could be a number of things, is it both equally? could be running up the side of the road, could be using lots of full lock as with Mercedes the wheels camber over heavily when turning. Could also slight camber combined with toe in. The fact it is only at that level after 22k worth of driving I personally wouldn't really worry about it just keep an eye on the next set...

The other thing that is highly likely that I didn't think of is tyre pressure as if they pressure is low and there is slight negative camber (as standard) this would happen very quickly so maybe low pressures as not in an offensive way I bet the pressures haven't been checked in the 22k they have been on the car. I would advise checking pressures every 2nd fill up at the petrol station or 500 miles ish.

[NickPicks]

22k out of a set of front tyres is not bad, but the tread depth looks Ok. The wear seems to be on the sidewall - you get a wear pattern in similar location if the tyre has been driven whilst flat. You also see similar wear patterns on cars on the outside sidewall when the tyre is rubbing a wheelarch.

I don't think driving on the hump of the farm tracks would cause this, I presume the bumpy bit is much just a few percent of the total miles travelled?

I'd suggest:
The car has been driven with low tyre pressures (and negative camber has meant that the inner edge has worn, but kept the outer edge off the road enough nor to wear) - just noticed that Autobulbs has also suggested this.
Something on the suspension is contacting the tyre (brake hose/ cable/ inner arch liner), but this is happening on both sides?

It's very unlikely to be 2 faulty tyres. I think the low tyre pressure / negative camber combination is most likely, and assuming your mum checks her tyre pressures as often as mine does (which is when it looks flat), I'd probably get the tyres replaced, have the wheel alignment checked, then keep an eye on them over the next couple of thousand miles.

[OddBallBoy]

I know it's an obvious question but have you had a good look underneath, round the wheel arch and on the strut to see if they're rubbing on anything on full lock?
I've never seen tyres wear like that and as there appears to be plenty of tread on the rest of the tyre (and it hasn't really worn the tread on the inside that much), rubbing on something seems the most reasonable explanation.
Maybe the steering stops or whatever Mercedes use on these to stop you turning the wheels further at full lock are missing or badly adjusted?

[Sam]

Hi,

This is my mum's Mercedes C-Class Couple AMG Sport she's had the car from new and tyres which are shown in the pictures have done 22,000 miles. Yesterday she had a service and Mercedes called to say about some wear on the inside of the front tyres which I thought would be something to do with camber / alignment or something but when I looked at the tyres it must be something else. Mercedes says they've never seen tyres wear like this before, they asked if we have planks or anything in the centre of the floor of our garage (which we don't) apart from that they have no idea what's caused it. They returned the car and left it at that.. The car is only 18 months old and I feel this needs to be looked into further but as the tyres are seen as a wearable part and not usually under warranty would I just be wasting my breath?

Inside wear on RWD Mercs is very common, no idea why they've told you they've never seen it before.

You can get the car aligned (camber/caster/toe) to try and correct it, but as above, 22k is damned good wear.

[Autobulbs]

Inside wear on RWD Mercs is very common, no idea why they've told you they've never seen it before.

You can get the car aligned (camber/caster/toe) to try and correct it, but as above, 22k is damned good wear.

If you look at the images its the sidewall not just the inside of the face of the tyre I think thats the issue and why its likely tyre pressure buddy.

[Sam]

If you look at the images its the sidewall not just the inside of the face of the tyre I think thats the issue and why its likely tyre pressure buddy.

More than likely, but to say they've never seen wear like it is absurd.

It's not the first car in the history of the world ever to be run on low pressure tyres.

[Jason Carson]

Thanks for replies,

The wear across the tyres is even and they still have some tread left even after 22k I've checked the pressures a few times over the past months and have put a bit in occasionally but I haven't seen them majorly flat at any time.

Yes it's both front tyres.

Still waiting for a reply from Mercedes.

[OddBallBoy]

If you look at the images its the sidewall not just the inside of the face of the tyre I think thats the issue and why its likely tyre pressure buddy.

But if tyre pressure was low enough to wear that high up the inside sidewall, would you not expect to see at least some similar wear on the outside sidewall?
Reason I'm puzzled is that when you see these Mercs on full lock, doesn't the inside wheel really tip onto the outside edge and therefore off the side of the tyre that's wearing?
If it was a combination of low pressure and toeing out too much, I'd have expected more wear on the tread as well?
Sorry, not questioning your experience/knowledge of these things, I know you guys know your stuff, just trying to get my head round the physics of what you're saying.

[NickPicks]

But if tyre pressure was low enough to wear that high up the inside sidewall, would you not expect to see at least some similar wear on the outside sidewall?

Yes, but the car has negative camber, so that lifts the outside edge slightly, which might just be enough to stop it wearing.