Cooper STT tyre deterioration issue, anyone else got similar?

[Jocklandjohn]

Bought a full set of Cooper STT's several years ago (I think it was late 2016 and so far have done around 28K miles on them. MOT tester drew my attention to sidewall cracking, which I'd noticed on the outer wall of one tyre, but which he showed me underneath was affecting all four tyres all around the sidewalls, not just in one or two places.

I did a web search and found several complaints about this exact issue from various buyers. I contacted Cooper UK this week and they asked about the tyre age - dates on sides show a 43/13 and 44/13 so we determined it was week 43 & 44 of 2013. Coopers response was a stock one that: "sunlight, wear, your use, etc etc all variables can affect tyres" and whilst, "yes there's a warranty," it's a 6 year warranty, but it starts from when they were made NOT from when you buy and use them and as dealers are independent once they leave Coopers, Coopers have no control over storage conditions nor time stored.

I've had this LR for over 25 years and put several sets of tyres on it and NEVER seen anything like this. I dont use chemicals or cleaners on them, they get minimal sunlight (Scotland!) and are correctly inflated for intended use. My spare, a Wildcat, is over 12 years old and looks immaculate and has zero cracking or perishing of any sort.

If it was one tyre I'd be philosophical about it but for all four to go at once is bizarre and concerning, particularly when a quick web search turned up comments like:

"After only 35,000 miles of pretty good driving, I had to replace my Cooper Discoverer A/Ts on short notice because the sidewalls had started to crack. When I had the truck in for service, the tech noticed the sidewalls cracking along the circumference of the tire (all the way around, on all 6 tires) in between the sidewall and the tread."

and

"I was just out rotating my tires and noticed that two of my four 285 Cooper STTs are cracking at the sidewall? This was on the inside of the two front tires. What gives? Should I be upset? The tires have about 3/4 tread left. Have not been out in the sun. Have not used any tire shine product that would effect the rubber. I am also suspicious that the two that are cracking were both made in the same week of 2008?"

and

"I just noticed today that quite a few places on my tires (Cooper Discoverer STT) are cracking/splitting in front of the tread lugs, mostly in the center lugs. They range fron about 1/4" to about 5/8", looks like the carcass is slowly seperating."

and

"Ugh. Cooper sidewalls cracking.  I bought these Cooper Adventurer A/T after reading good things. 265/75r16 with aftermarket FN Wheels and a 3"/2" level. They've been on my truck for 8 months and maybe 10k miles. Mild off-roading. I mean like, putting around the farm at 5mph or treking across clay fields to dirt tracks. I keep them between 40-42psi. The cracking is minimal but it's there on three of four tires. I didn't notice it until rotating tires and detailing today. "

Final response to me from Coopers is basically: out of warranty, could be anything, nothing to do with us, sorry.

You can see the cracking in the pictures, also how much tread is left. Also pic from US commentator with same issue.

Any of you had this problem?

So - if any of you are considering buying Cooper STT's - maybe think twice about it. Personally I'll never buy their products ever again.

 

 

This is my front tyre.

This is my back tire.

Tread rear

Tread front

[Maverik]

Maybe not what you want to hear, but 9 year old tyre and its cracking, not a massive suprise, its rubber which ages. Yes you can increase the age by altering the storage conditions but that will ony slow the effect.

My tyres never get to that age mainly due to they wear out before they crack.

There's a reason why commercial vehicle rules state tyres should be no older that 5 years old.

What is your expectation of tyre life?

The example you gave above (Photo) the person had the tyres for 2 years and they had cracked - yes I'd say this was a problem, but not after 9 years of life and 6 years on "the road".

Mav

[Chicken Drumstick]

Tyre cracking is pretty common tbh. I wouldn't worry too much unless its really bad. As a rule they will still be legal and pass an MoT.

As for the age... meh. Had tyres crack in less time. Could be many factors. And as for the warranty, it can't be point of sale date unless you bought direct from Cooper. UK law is your agreement with the seller. And a seller could keep the tyres for 10 years and then sell them. The maker has no control over this.

[Jocklandjohn]

1 hour ago, Maverik said:

Maybe not what you want to hear, but 9 year old tyre and its cracking, not a massive suprise, its rubber which ages. Yes you can increase the age by altering the storage conditions but that will ony slow the effect.

My tyres never get to that age mainly due to they wear out before they crack.

There's a reason why commercial vehicle rules state tyres should be no older that 5 years old.

What is your expectation of tyre life?

The example you gave above (Photo) the person had the tyres for 2 years and they had cracked - yes I'd say this was a problem, but not after 9 years of life and 6 years on "the road".

Mav

My expectation was for them to be as long lasting as the previous sets!  Thats really the only yardstick I'd have from personal experience.

 

1 hour ago, Chicken Drumstick said:

Tyre cracking is pretty common tbh. I wouldn't worry too much unless its really bad. As a rule they will still be legal and pass an MoT.

As for the age... meh. Had tyres crack in less time. Could be many factors. And as for the warranty, it can't be point of sale date unless you bought direct from Cooper. UK law is your agreement with the seller. And a seller could keep the tyres for 10 years and then sell them. The maker has no control over this.

Aye the MOT tester said they were ok for use currently, but he was a tad perplexed as he's the same lad who's tested it every year for 15 years or so and noted it as something he's not seen very often. Maybe with 10+ year old tyres but for 5+ he thought it a bit premature.

Edited April 1, 2022 by Jocklandjohn

[Eightpot]

I wouldn't think it abnormal to get some cracking at that age, and I guess with specialist tyres like these with tall tread blocks there's always going to be some compromises - the cracking might be prevented if they used a softer compound, but then wear would accelerate and they'd be squirmy going round corners.  At least the UV isn't so strong where you are, I have to keep the tyres on my african Defender covered up with thick uv resistant tarpaulin which turns to dust and has to be replaced every 6 months! 

[Jocklandjohn]

I'm resigned to new tyres (!) I was just curious after reading several other complaints whether there was a (known) issue and if anyone had experienced similar. I noticed the cracking on one tyre at the start of lockdown but hadn't realised all four had done the same. Never seen it on any tryres I've owned previously.

Ah well...another item line on the list of Land Rover consumables....!

[cackshifter]

The other thing that can accelerate cracking is running with pressure too low - not saying that is the case with  the OP. I have just replaced a set of Cooper STMaxx at 10 years old and there was cracking (they have the same carcass), but I don't think that is too bad a life. I think they may be more prone to cracking than other brands but they survived various other abuses unscathed.  BFG were much more expensive..... 

[Jocklandjohn]

6 hours ago, cackshifter said:

The other thing that can accelerate cracking is running with pressure too low - not saying that is the case with  the OP. I have just replaced a set of Cooper STMaxx at 10 years old and there was cracking (they have the same carcass), but I don't think that is too bad a life. I think they may be more prone to cracking than other brands but they survived various other abuses unscathed.  BFG were much more expensive..... 

Aye, many variables! Have to say their wet grip and snow performace was excellent plus how quiet they are. Shame they've fallen apart so 'quickly' is all I can say!

[Chicken Drumstick]

On 4/1/2022 at 5:53 PM, Jocklandjohn said:

I'm resigned to new tyres (!) I was just curious after reading several other complaints whether there was a (known) issue and if anyone had experienced similar. I noticed the cracking on one tyre at the start of lockdown but hadn't realised all four had done the same. Never seen it on any tryres I've owned previously.

Ah well...another item line on the list of Land Rover consumables....!

I have STT’s on my 90. I’ll have a look at the date code too. 
 

TBH - I like the “looks” of the tyre and on road they are nice. But they have been the most hopeless mud terrain I’ve ever used. Not that they make them any longer. But I’d not buy a 2nd set. 

[taurion]

There is a set  of Cooper Discoverer tyres outside my door from Holland , half worn, date 3715 with sidewalls cracked all round, so unfortunately you are not alone.

[Flash17]

I had this exact thing with this exact manufacturer (cooper 285x75 r16 ST) after 3 years and approx 30k miles of use, Cooper exchanged the 2 worst (fronts) under warranty but 2 years later cracking was back this time cooper refused to acknowledge and I ditched them to a mate for off-road use only and switched to BFG Goodrich ATs, which have now been on the motor 60k mile and near 8 years without issue.

Shame as was really happy with the tyre, worked well in snow, gave good wear rate, and was quieter that full muds on motorway

I wasn’t willing to risk a blowout at 70 on the motorway and swore I’d never go back to Cooper and haven’t since.

good luck getting Cooper to cough up despite an obvious issue that other manufacturers don’t have.

Edited April 2, 2022 by Flash17

[Jocklandjohn]

21 hours ago, Flash17 said:

I had this exact thing with this exact manufacturer (cooper 285x75 r16 ST) after 3 years and approx 30k miles of use, Cooper exchanged the 2 worst (fronts) under warranty but 2 years later cracking was back this time cooper refused to acknowledge and I ditched them to a mate for off-road use only and switched to BFG Goodrich ATs, which have now been on the motor 60k mile and near 8 years without issue.

Shame as was really happy with the tyre, worked well in snow, gave good wear rate, and was quieter that full muds on motorway

I wasn’t willing to risk a blowout at 70 on the motorway and swore I’d never go back to Cooper and haven’t since.

good luck getting Cooper to cough up despite an obvious issue that other manufacturers don’t have.

Thanks for that Taurion and Flash. Interesting to hear first-hand accounts of the same problem. It was very easy to find similar examples online for this brand and Cooper are not interested. I quoted them the various complaints I'd found, with screen grabsa, and they've said tough, out of warranty, you're on your own.

Caveat emptor!   Last Cooper tyre I'll ever buy.

 

 

[Chicken Drumstick]

Not sure which number is the date code on these. No real cracking, just some stress marks if you zoom right in. 
 

235/85’s. 

[Dave W]

Mine did this on the motorway at 70MPH, no warning, no vibration and as far as I know the pressures were fine up until that point. Inside side wall was completely fine, not a mark on it.

I'd been told by an Australian that these tyres had some issues with structural failure but assumed it was an extreme heat issue or something and dismissed it. This was one of a pair I bought in 2016 to replace the 4 year old ones that I'd driven around Australia. I've lost all trust in these tyres as a result and have replaced them all with a different make. I've had tyres give up on me in the past due to punctures but never had one like this where the sidewall split around the entire circumference and have lost all confidence in them as a result.

I'd be concerned that any sign of cracking, especially on the outer sidewall, might be a sign that a similar structural failure is occurring, if that's what happened to mine.

[Jocklandjohn]

On 4/5/2022 at 9:53 AM, Dave W said:

Mine did this on the motorway at 70MPH, no warning, no vibration and as far as I know the pressures were fine up until that point. Inside side wall was completely fine, not a mark on it.

I'd been told by an Australian that these tyres had some issues with structural failure but assumed it was an extreme heat issue or something and dismissed it. This was one of a pair I bought in 2016 to replace the 4 year old ones that I'd driven around Australia. I've lost all trust in these tyres as a result and have replaced them all with a different make. I've had tyres give up on me in the past due to punctures but never had one like this where the sidewall split around the entire circumference and have lost all confidence in them as a result.

I'd be concerned that any sign of cracking, especially on the outer sidewall, might be a sign that a similar structural failure is occurring, if that's what happened to mine.

Yikes thats a bit drastic!  That was what I was afraid of, and what several other posters I've read described. 

I'm taking things very gingerly until they're replaced!

[landroversforever]

Mate of mine had a new set go properly out of round very quickly. Cooper didn’t want to hear and blamed everything but the lack of quality in their tyre  

[Jocklandjohn]

13 hours ago, landroversforever said:

Mate of mine had a new set go properly out of round very quickly. Cooper didn’t want to hear and blamed everything but the lack of quality in their tyre  

Funny how when you dig a wee bit you start hearing a lot of these stories....

[landroversforever]

@Tim2809

[Tim2809]

Sorry for being late to the party, yes my stt pro did 11000 miles before being scraped all went out of shape. Cooper were not interested blaming suspension bushes, shocks, towing too much off road, too many road miles running too heavy regularly. . They would not inspect even when i offered to pay carriage for them .  

[Jocklandjohn]

Chimes with my experience and numerous folks who’ve commented here and on various forums UK and abroad. Pfft what a waste of money buying Cooper.

[Jocklandjohn]

Update on this - just discovered this is a HUGE and ongoing problem with Cooper tyres - just came across this lot, although its talking about the US market it would appear from the experiences offered by folks on here to my original post, that the issue may be more widespread, so if any of you are using them you'd best be aware of whats going on:

 

https://www.google.com/search?client=firefox-b-d&q='cooper+discoverer+sidwall+failure'

 

[Ed Poore]

You think that's bad I had General Grabber ATs on my first L322 do that after about a year and 6k 

By contrast if anyone wants a long lasting tyre then the 6 I've just removed from the 6x6 are 21 years old and look in better shape than most modern tyres after a month. They are 13 ply though... 

[markyboy]

On 4/19/2022 at 8:06 AM, Jocklandjohn said:

Update on this - just discovered this is a HUGE and ongoing problem with Cooper tyres - just came across this lot, although its talking about the US market it would appear from the experiences offered by folks on here to my original post, that the issue may be more widespread, so if any of you are using them you'd best be aware of whats going on:

 

https://www.google.com/search?client=firefox-b-d&q='cooper+discoverer+sidwall+failure'

 

A sidewall bulge will not be the same as the issue of "dry rot" or "ozone cracking", which is what your tyres appear to be suffering from. A sidewall bulge suggests a structural problem, a weakening of the sidewall usually caused by a joint in the carcass failing or the body plies separating. This is an inherently dangerous situation, as I'm sure you're aware. Ozone cracking should not affect the structural integrity of the tyre, unless it is bad enough to expose the carcass plies. 

[Desert Cat]

 

Hello,

I don’t know if it’s the same thing but I had this incident while driving 50mph at the highway as for suddenly this happened 

Cooper STT pro 265/75-16

tyre manufacturer date is week 19 year 2019

Quote

 

 

 

 

Edited January 31 by Desert Cat