Dunlop winters sidewall damage

[SmartMAC]

I noticed yesterday that one of the front tyres on my winter set (standard Mercedes set bought from dealer via eBay) has a bump on the sidewall. It is the size of a tennis ball and protrudes on the sidewall.

Other than that, the car drives well and there is no vibration through the steering wheel. There is no external damage on the tyre that I can see. There are so many pot holes around that I don't discount this as the possible cause but I was wondering if it could be a manufacturer issue so I could get the tyre replaced FOC.

I am putting the summer tyres back on today to be on the safe side and I have emailed the parts department from the dealership I got the wheels from for advice.

Anybody has had a similar issue. How likely is Mercedes to look into this considering I got them an a very preferential rate in the first place.

I'll put some pics tonight when I swap the wheels.

 

[developer]

Generally when you buy from a tyre shop and there is a quality query, the process is to buy another tyre, while the tyre shop sends yours away to the manufacturer for analysis.

i suspect MB would want you to follow the same process.

Unfortunately, with such bad roads, I suspect they will be claiming user error as a starting point.

 

[redbaron]

User Error ? Road surface damage is a nicer way to phrase it. Either way suspect they wont pay out. Am sure they will send away if you request it but wouldnt get your hopes up.

 

[grober]

What's the tyre manufacture date? and does it match with the otherwinter tyres on the car you got at the same time?

 

[grober]

In case you don't know what to look for on the tyre side-wall look for a mark similar to this. In this example the number 1412 indicates the tyre was manufactured in the 14th week in the year 2012.

 

[SmartMAC]

The tyres were all bought at the same time so they should have the same build date.
I got a reply from the dealer suggesting to take the wheel to them next week as they have a 'tyre expert' on site.
I have just finished swapping the wheels for the summer ones and on close inspection, there is no other damage other than the tyre. Alloy is perfect inside and outside so less likely to be pot hole related I guess.

 

[grober]

The tyres were all bought at the same time so they should have the same build date.
I got a reply from the dealer suggesting to take the wheel to them next week as they have a 'tyre expert' on site.
I have just finished swapping the wheels for the summer ones and on close inspection, there is no other damage other than the tyre. Alloy is perfect inside and outside so less likely to be pot hole related I guess.

Not questioning that assumption but winter tyres are a product that can "sit on the shelves" for a year between seasons. My experience of buying winter tyres over the years is like the TESCO " Bargain net of Oranges" ----there's often a green one in there. If by any chance the tyre that failed turned out to be considerably older than the others that might explain its failure or that it came from a different production run that's all.

 

[johnsco]

Side-wall failures are a common problem with tyres that have aged ... Even if they have had no use.
I made a mistake about 3 years ago that could have been disastrous.
At the time, we ran two 1997 E300TDs,
They both had unused spares on steel wheels.
When I needed two replacement tyres, I put them both on one of the cars and used the steel wheels for snow tyres.
Within 12 months, both the old tyres had side-wall bubbles in several places.
Even worse ... Both failed on the inner wall of the tyre and it would have been very easy to fail to recognise what was happening.

 

[SmartMAC]

The tyres have a date of 1211 on them so I guess it's December 2011. I only got them in October 2012.

Pics:
http://db.tt/SLgg92IR
http://db.tt/3WdzqGEp

What do you think?

 

[toolman1954]

Using Grobers useful date calculator and your tyre code of 1211, puts your tyre manufacture date in March of 2011 (12th week of 2011), and not December.

 

[SmartMAC]

 

[SmartMAC]

Went to the dealer and the tyre technician spotted a bit of rubber stuck on the alloy wheel which means the tyre has been compressed against the alloy wheel at some point so not much point in perusing this further as it is very likeky to be pot hole damage.
On the bright side, the price for the new tyre was very competitive so at least is sorted.

 

[Dieselman]

That tyre has been egged when mounting a kerb.