Wear, or a faulty tyre?

[E55BOF]

What does the team make of this:



The CLS I just sold failed its first MoT on this dangerous (it certainly was...) tyre fault. It was on the inside edge, so not visible unless you got under the car, and having had a knee replacement recently, I had not been under the car for a few months, but the car had done very few miles in that time.

The tyre was ready for replacement anyway, and I knew that, but the damage was confined to the patch you see; the other 75% of the shoulder was worn but undamaged. The other rear tyre was fine. There was no indication of wheel imbalance.

The very nice chap who bought the car opined that it was due to the camber of the wheel, and would not have it otherwise, so I didn't argue with him (I wanted him to buy the car...), but I think he's wrong, because it was only in one place. I can't see other than it must have been either a fault in the tyre (Goodyear Eagle F1, not Yingtong Ditchfinder), or a deep cut that started it. Has anybody ever seen anything like that before, and if so, do you know the cause?

 

[ALFAitalia]

Alignment...either way to much camber...or a bit too much toe out. More likely the latter IMO.

 

[E55BOF]

I had full suspension alignment done 2000 miles previously. If alignment was the cause, surely it would have been worn equally badly all the way around, not just in that one spot?

 

[SpikyMikey]

What does the team make of this:

View attachment 169459

I'm no expert, but I'd say it was probably fooked...

 

[SpikyMikey]

I'm no expert, but I'd say it was probably fooked...

Seriously though, isn't wearing tyres on the inside edge known to be a Mercedes "thing"?

 

[Gazwould]

Many cars have it , the most sensitive setting is toe as Alfa has mentioned .

Any wear in a bush etc or tiny error in alignment .

 

[E55BOF]

All true, but not localised wear in one spot like that. That's what baffles me...

 

[Bobby Dazzler]

I don’t have a photo however I had a tyre which had a tear or cut on the inside shoulder, which looked like it had been caused by damage, however there was accelerate wear on the shoulder either side of the damage.

In my case the damage was potentially deeper and the wear more localised making it easier to jump to a conclusion (whether right or wrong), however I suspect that over time the accelerated wear would spread further making the damage less obvious.

If you regularly drive on - or close to - full lock then it will accelerate wear around the point of damage, due to the stress being placed upon the tyre - and specifically the inside shoulder - when manoeuvring in tight spaces.

Apparently damage to the inside edge is often a result of straddling speed cushions, especially when the surface of the speed cushion breaks up creating a sharp edge, due to weight of the cars not being spread across the full width of the tyre.

 

[st13phil]

All true, but not localised waer in one spot like that. That's what baffles me...

Out of curiosity, did the rim on which that tyre was mounted have an unusually large balance weight?

 

[E55BOF]

It was a rear tyre, so full lock manoeuvring (which I don't do much of anyway) would not have been a factor.

Yes, there were quite a lot of balance weights on the rims, which I suspect had needed quite heavy refurbishment. All the wheels were like that, though.

 

[MrGreedy]

My guesses (am I allowed two?) are:

Rim concentricity issue(s); or,

Hand (foot )brake turn.

 

[st13phil]

Yes, there were quite a lot of balance weights on the rims, which I suspect had needed quite heavy refurbishment. All the wheels were like that, though.

The reason I asked the question about the balance weights is that due to the manufacturing process, tyres aren't perfectly uniform in their structure. An unusually high balance weight requirement may suggest that there was a spot on the tyre where the reinforcing cords were closer to the tread root than elsewhere.

But as has also been suggested, any minor damage to the tyre will often cause accelerated localised wear so it could just as easily be that.

 

[ALFAitalia]

TBH looking at the rest of the tyre it was knackered even without the edge wear.

 

[E55BOF]

My guesses (am I allowed two?) are:

Rim concentricity issue(s); or,

Hand (foot )brake turn.

I've never tried a parking brake turn with a foot-operated parking brake; it strikes me there might be rather a lot of practice required to get the coordination right.

TBH looking at the rest of the tyre it was knackered even without the edge wear.

As I said, I already knew it required replacement.

 

[John N]

I'm no expert, but I'd say it was probably fooked...

Well Fooked!

 

[John N]

What does the team make of this:

View attachment 169459

The CLS I just sold failed its first MoT on this dangerous (it certainly was...) tyre fault. It was on the inside edge, so not visible unless you got under the car, and having had a knee replacement recently, I had not been under the car for a few months, but the car had done very few miles in that time.

The tyre was ready for replacement anyway, and I knew that, but the damage was confined to the patch you see; the other 75% of the shoulder was worn but undamaged. The other rear tyre was fine. There was no indication of wheel imbalance.

The very nice chap who bought the car opined that it was due to the camber of the wheel, and would not have it otherwise, so I didn't argue with him (I wanted him to buy the car...), but I think he's wrong, because it was only in one place. I can't see other than it must have been either a fault in the tyre (Goodyear Eagle F1, not Yingtong Ditchfinder), or a deep cut that started it. Has anybody ever seen anything like that before, and if so, do you know the cause?

If the Damage is just on the Spot we can see in the Picture, I would suggest "Aquaplaning" I had very similar Damage on a Renault Laguna many moons ago!

 

[alabbasi]

Suspension wear. Maybe a shot airbag is sitting low ok one side

 

[MrGreedy]

I've never tried a parking brake turn with a foot-operated parking brake; it strikes me there might be rather a lot of practice required to get the coordination right.

It was a tongue in cheek suggestion. The thought of trying it gets the mind racing of all the ways it could be cocked up and result in 'sub optimal' outcomes.

 

[E55BOF]

If the Damage is just on the Spot we can see in the Picture, I would suggest "Aquaplaning" I had very similar Damage on a Renault Laguna many moons ago!

Not that; it would not be just on the shoulder, and I'd have known about it if I'd been driving anyway.

Suspension wear. Maybe a shot airbag is sitting low ok one side

Not that either; the suspension was fine, and the damage would not be localised to just one point on the tyre.

 

[ALFAitalia]

I looks worn all the way round from what I can see in the pic ....just worse at that point.....there will always we one point that wears faster for whatever reason....and once its through to the softer inner rubber wear accelerates.