EQC Dangerous Tyre Wear - Please Check Your Tyres!

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ramjet666

New Member
Joined
Nov 2, 2023
Messages
7
Location
Colchester
Car
Mercedes-Benz EQC 400 Premium
TL;DR
In our experience and from googling this issue seems to be a common problem.
Your front tyres will wear excessively on the outside edge to the point where the canvas is showing way before the tread wears out.
Possibly unknown to you the rears will wear on the inside edge and split (so unseen) to the the point where a rapid deflation happens (best case could be a lot worse). This just happened to us.

Longer;
A few months back we replaced our front tyres owing to the above issue, I decided to try Hankooks this time to see if it's an issue with Michelins.
All seemed well until last night when a rapid deflation happened with the OSR tyre (Michelin). I was thinking oh great we had a nail in it or something like that.
Anyway after getting recovery out they took the wheel off and the inside edge was very badly worn to the canvas and split. The tyre had plenty of tread across the full width.
This was a bit of a shock to see as we then looked at the NSR tyre and it showed the same effect, a circumferal split around the inner edge between the sidewall and tread.
Tyre pressure are all nominal btw.
Some mention ah this is the weight and torque of the car doing this, really?
Recovery guy mentioned to get the rear geometry checked but others who have had this happen did this and Merc say it's fine.

What's going on here, because it seems not right to me?

Car is currently being taken to Merc dealer we bought it from, be interested to hear what they say.

OSR
IMG_20231101_195544.jpg
NSR
IMG_20231101_195630.jpg
 
How many miles have those tyres covered, when we’re they fitted, when we’re they made, and when was a wheel alignment last performed?
 
We bought the car with 13k miles on it, guessing they could be the original rears from new not sure when made. Car has now done 27k. Alignment was checked when we replaced the fronts at 24k and was OK.
 
Clearly the alignment is NOT correct or that could not happen......or at the very least the stipulated settings are not correct. You need to take it to someone who knows a about alignment....not just someone who will just stick to factory settings.
The factory setting on most FWD ALFA was found to have way to much toe out resulting in worn front inner edges. This is general knowledge now with most owners getting theirs set a close to zero toe. Maybe there is a similar issue with this model.
Another thing it shows me is that you don't check your car over or your tyre pressures too often. No way I would have missed my tyres getting like that....even if it was just during cleaning. If anything had happened as a result of tyre failure at speed the responsibility would have been yours.
 
It does sound more like alignment, however, straddling speed humps especially the ones with raggedy edges also causes invisible inside edge wear...
 
We bought the car with 13k miles on it, guessing they could be the original rears from new not sure when made. Car has now done 27k. Alignment was checked when we replaced the fronts at 24k and was OK.
If they’ve done 27,000 miles than that’s fairly good, as and whilst they might have lasted a little longer without the split, I suspect that they were nearing the end of their useful life.

My first thought is that it could likely be down to straddling a whee either side speed cushions. This accelerates wear on the inner edge as there’s a lateral load as the tyre passes.

Cushions often fail on the left and right hand edges, and the speed cushion breaks up. The sharp/rough edge accelerates wear further still and can physically damage the tyre in sone cases too.

Speed cushions have been known to rip off tyre tread blocks completed, and once they start to delaminate they flap around, tear and will then fail altogether fairly quickly after that.

I would say it’s best to not straddle them, and if you must do it occasionally ally and slowly. Better is to alternate running your left side and right side wheels over the top of the cushion (slowly).

It could be that the wheel alignment was not performed, or performed correctly - find a place which specialise in alignment, not just a bolt on to tyre fitting- the difference in their work is marked.

I don’t think wheel alignment was the cause of that personally.
 
Can you adjust the rear geometry?
 

INTERESTING COMMENT ABOUT THE EQC BEING PRIMARILY FWD WITH RWD ONLY CUTTING IN WHEN NEEDED PUTTING A GREATER STRAIN ON THE FRONT TYRES IN NORMAL CONDITIONS????
 
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My guess is your EQC is a big heavy car and would be inclined to roll when cornering. Mercedes employed aggressive torque distribution to individual wheels to counteract this handling tendency and the components which soak up the bulk of these forces are the tyres particularly when they are presented to the road surface on edge. The result is a stable car but at the expense of excessively uneven tyre wear?
 
Although camber bolts from factory are non adjustable, they can be replaced with adjustable items.
Wheels in Motion in Chesham can do it (give them your VIN and they can get them into stock for you).
Im sure other places around the country who are experienced geometry specialists can do the same.

Do ensure that even if they have a Hunter set up, that they actually have the full data licence for your exact model- if you end up with “grey” figures on the print out, they don’t have the access to that data.
 
Although camber bolts from factory are non adjustable, they can be replaced with adjustable items.
Wheels in Motion in Chesham can do it (give them your VIN and they can get them into stock for you).
Im sure other places around the country who are experienced geometry specialists can do the same.

Do ensure that even if they have a Hunter set up, that they actually have the full data licence for your exact model- if you end up with “grey” figures on the print out, they don’t have the access to that data.
Not something for me I'm afraid. The car is due to be replaced in the near future, Had I known about them 2 years ago then I would have gone down that route..
 
Although camber bolts from factory are non adjustable, they can be replaced with adjustable items.
Wheels in Motion in Chesham can do it (give them your VIN and they can get them into stock for you).
Im sure other places around the country who are experienced geometry specialists can do the same.

Do ensure that even if they have a Hunter set up, that they actually have the full data licence for your exact model- if you end up with “grey” figures on the print out, they don’t have the access to that data.
Thank you, that is useful information that I was not aware of. I will give this some consideration.
 
The front camber on many MB cars is adjustble via the slotted hole (3 positions) in the front link arms . not sure if that is true of EQC.

Were the tyres ones specifically built for an EV ?

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Car is back from Mercedes dealer, with two new rears (Hankooks, same as front) and alignment was checked. See image for alignment results of before/after.
Can those figures account for what wear we have experienced?
Merc service rep had very little to say about the issue, apart from mentioning the alignment report when asked, but I get the feeling from him he was being a bit cagey.
To add to what someone said above, you cannot actually see this wear when looking from the side into the wheel arch, you have to look from the rear middle underneath and preferably with a torch.
IMG_20231110_0001-blurred.jpg
 
So they can adjust the rear camber ?
 
If they’ve done 27,000 miles than that’s fairly good, as and whilst they might have lasted a little longer without the split, I suspect that they were nearing the end of their useful life.

My first thought is that it could likely be down to straddling a whee either side speed cushions. This accelerates wear on the inner edge as there’s a lateral load as the tyre passes.

Cushions often fail on the left and right hand edges, and the speed cushion breaks up. The sharp/rough edge accelerates wear further still and can physically damage the tyre in sone cases too.

Speed cushions have been known to rip off tyre tread blocks completed, and once they start to delaminate they flap around, tear and will then fail altogether fairly quickly after that.

I would say it’s best to not straddle them, and if you must do it occasionally ally and slowly. Better is to alternate running your left side and right side wheels over the top of the cushion (slowly).

It could be that the wheel alignment was not performed, or performed correctly - find a place which specialise in alignment, not just a bolt on to tyre fitting- the difference in their work is marked.

I don’t think wheel alignment was the cause of that personally.
An interesting point you make about straddling speed cushions/bumps that is a possibility and likely accelerated with the extra weight of the vehicle.
But I would think the fronts would exhibit the same inner wear as what the rears have shown if that was the case?
I think you are right about the previous wheel alignment, this was done at ATS Euromaster and I don't think they had the necessary car alignment details.
 
The front camber on many MB cars is adjustble via the slotted hole (3 positions) in the front link arms . not sure if that is true of EQC.

Were the tyres ones specifically built for an EV ?

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Yes, the car came with Michelin Pilot Sport 4 SUV (Reinforced XL) tyres.

(The MacMaster video is very true, not much mentioned out there yet about tyre wear!!)
 
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