Split walls on Cooper ST Maxx

[KeithB]

In September last year I put on six 285/70/R17 Cooper ST Maxx on my 200 Series, with two spares on the back. Since then I have covered only 17,000km and have rotated the tyres several times.
Coming east over the Simpson towing a trailer a month or two ago, I dropped pressures to 16/19 hot and kept an eye on tyre temperatures, which stayed under 60 degrees. I was not overloaded.
Arriving in Birdsville I found that both rears had split walls around the white lettering. Coopers have offered to replace them. But I am concerned about maybe a bad batch and what about the other four?
A tyre dealer I spoke to said that he was always getting Coopers back with split walls and Coopers just keep replacing them and keep quiet about it. He said there was never a problem with BFGs or Mickey Thompsons.
My last set of the same Cooper tyres were fine, but I did not do any sand work and they never went below 24 psi.
Can anyone tell me whether these Cooper tyres are in the habit of splitting?
Cheers
Keith

[Green rv]

Hi Keith

i was working in a 4wd workshop just over 2 years ago
the boss had two cars with coopers on, both got splits in the side walls
and also talked to a lot of customers(from caravaners to extreme 4wders) that had them with the same problem
the second thing i always heard, was slippery in the wet

thats just what ive seen and heard about them

edit -- should add that the other 50% were happy with them

 
Adam

[isportfish]

Just traded my ute recently shod with ST Maxx. Travelled 80000km and did not encounter splitting issues such as yours. Only positives from me and happy with the overall performance on all surfaces and quietness compared to previous tread pattern.
 

[sablesoft]

Hi,

The only split I have had in my Cooper ATR/AT3 tyres were caused by a 2 inch section of one or those knives with snap off blades, It cut a BAD gash in the side of the ATR tyre side wall near the tread, cutting cords etc, only had about 5000k on the tyre. Not repairable so had to buy a new tyre, very pissed off at the scumbag who dumped a broken knife blade on the road.

Ray

[Skinnee]

I heard the first couple batches had issues , when did they come out

[99disco]

Yep it's a cooper thing, heaps of Shit.

Father in law has had st and ht now do the same thing, keeps buying the bloody things though.

Shane

[Snapman007]

Might be helpful to others if folks that have had issues post the date stamp on their tyres so we can see if it's general or isolated to a certain manufactures batch.

[cruza driver]

I also heard it happen to some of the early batches, but not sure on what size.

I have ST Maxx's on my BT 265/70/17 and have covered approx. 44k

Half would be towing the Expanda and not just on the Bitumen either with trips through outback central QLD with the van on.

[geopaj]

My last set of the same Cooper tyres were fine, but I did not do any sand work and they never went below 24 psi.

Definitely doesn't sound right. For reference, I also crossed the Simpson towing about the same time as you last year (early October). I did nearly the entire crossing with 10psi in the front, 10psi in the trailer and in the back whatever pressure was required to get equal bagging (more weight in the road).

I had no issues with tires at all (definately no sidewall splitting). 4wd has BFG LT AT tires, and the camper has Kumo LT AT tires.

[dooguss]

 I first put my st max"s on the prado before heading to the cape in 2012, and when we came home I found 1 tyre had a split in the side wall. So I took them back into Goodyear and had the bad one changed for a new one.
85k on them now and not an issue since,  I"ll be putting coopers back onto my car again no hesitation.

[KeithB]

My tyres have "4712" stamped on them, which I think means they were made in the last week on November 2012. They were fitted in September 2014, which makes them a very early batch and very old stock.
To make matters worse, the dealer (who seems to be  a genuine bloke) says he did not buy them from Coopers, so I think they might be a dodgy import, which I don't think Coopers are aware of and may negate my Coopers warranty.
The dealer says he can't replace the split ones but will refund after an inspection.
My concern is that, if I deflate the tyres again for sand work, I will have to more split rears and he and I will be having the conversation all over again.
I have asked the dealer to sharpen his pencil and see if he can do a replacement set of BFGs or Mickey Ts, neither of which seem to have a splitting problem at low pressures. Will be interesting to see how I go on that one.
Mind you, I really like the ST Maxx tyres. They are great on the road, grip well in the wet, are not too noisy and are excellent off road. Shame about the side walls though.
Keith

[BTMNDR]

Yep it's a cooper thing, heaps of Shit.

Well, I'm really happy with my "heaps of Shit" A/T3s, 80,000 km & still going, no cracks, been aired-down to mid 20s. Excellent tyre in my experience.

[patroldude]

Mickey Thompson ATZ P3 or the MTZ. Had 3 sets of the MTZ now no challenges with them at all.

[HKB Electronics]

When I was getting mine fitted the supplier mentioned there had been an issue, he also
said Cooper were trying to do away with the white lettering as it has something to do with it.

I don't believe it affects the safety of the tyre is just a cosmetic?

[Steffo1]

Yep it's a cooper thing, heaps of Shit.
Shane

I don't normally return comment to a quote like this but, after having done some 85,000k on Cooper STs which included the GRR, Cape Leveque, Gunbarrel, Simmo & quite a few other jaunts they succumbed to one slow puncture caused by a piece of metal from the old Hatches Creek mine.
I've just got rid of the  last set of STs which were good for 95,600k, also with a fair bit of non bitumen work (western NSW & Vic High Country to name a couple). Did not have one problem with them.
I've  replaced them with ST Maxx as our days of super remote/harsh trips are behind us so it will be interesting to see how they go in regard to the OP.
And NO, I'm not a dedicated Coopers man. I have Maxxis Bighorns on my 'tilley & they're a good tyre for what I use it for. They have chipped a little but for where I've had them I think any tyre would.
Maybe some tyres are better suited to certain vehicles than others & corresponding driving styles/techniques.
Steve

[KeithB]

Mine have split either side of the white lettering and one has gone right through the carcass, which suggests that it's a little more than cosmetic.
It is interesting that only the rears, which has a lot of weight on them, are showing the problem.  I think 16 psi cold and 19 psi hot should be fine for a proper off road tyre on sand.

[gronk]

I think 16 psi cold and 19 psi hot should be fine for a proper off road tyre on sand.

As long as they don't get hot !!

Normal sand work is fine, but even a run up the beach on the hard packed sand at 70 k/ph can put some serious heat in them at times....plus the fact they are Coopers !!   

They have the biggest advertising budget ( and have done for yrs ), which means they have got a good market share, but it's well known they are a very ordinary tyre......just ask a tyre shop anywhere in the outback !!

There are people who will defend them till the cows come home, because they haven't had problems with them, but if you took a survey, they would be by far the most complained about tyre out there !!

[dazzler]

I dont agree with dropping tyres to 16 on hard surfaces. 

A tyre that is that low can ripple along the sidewalls which causes a wave type of pattern that is what you see in tyres that have blown due to being run very low due to a slow leak.

Happy to be proved wrong but I doubt there is any tyre manufacturer that would replace a tyre under warranty if the owner said it was run at 16psi for any length of time.


I know that is not the flavour at the moment in 4wd circles but my 2c anyway.

[KeithB]

My 16/19 hot was over the Simpson in sand in cool weather. The tyres stayed at about 55-65 degrees, depending on whether or not they were in the sun.

[dazzler]

My 16/19 hot was over the Simpson in sand in cool weather. The tyres stayed at about 55-65 degrees, depending on whether or not they were in the sun.

Thats why the heat is not really relevant.

They are still able to ripple.  Maybe not enough to get hot enough to fail, just enough constant flexing to create cracks.  If they got hot enough then they would have fractured and failed.

Think of it this way.  Take a teaspoon and slowly bend it a little in the middle and then back - Uri Geller style.  Just slowly, not enough to get hot, just enough to bend.  Eventually it fails even without the heat.

In our off road race buggies we always played around with tyre pressures and would try and get low to take the jarring out of your kidneys and hands.  Over six hundred k's it made a big difference.  Maybe 25 was the lowest I can recall ever running.  We would damage rims all the time and they failed really quick when the pressures started dropping - even before you felt it low in the handling.

Meant to add - Being the backs that cracked they endure a lot more force from the trailer than the fronts.  They were probably bagging out way more than the front

[slydar]

Well, I'm really happy with my "heaps of Shit" A/T3s, 80,000 km & still going, no cracks, been aired-down to mid 20s. Excellent tyre in my experience.

same here, even though I look suspiciously at the decorative imprint in the side walls and wonder if it could be a weak point in later years of the tyres

[gronk]

I dont agree with dropping tyres to 16 on hard surfaces. 

Neither do I, but if you are doing sand driving up a beach, then you have no choice.....unless you are part of that group of people that think power overcomes all obstacles and lowering pressures is for pansies !!

I had a blowout along the Cordillo Downs track a few yrs ago...started out at a 60 k/ph track, but got faster as we travelled south, and when I had a blowout, we were travelling at approx 90 k/ph...with 28 psi in the tyres.....rear tyre blew out ( we were also towing a KK at the time ) and when I felt the other good tyre it was VERY hot...lesson learnt....if you lower pressures, keep the speed down !!

[KeithB]

If they were rippling, Dazzler, wouldn't the cracks be axial rather than radial?
Keith

[Elky]

As long as they don't get hot !!

Normal sand work is fine, but even a run up the beach on the hard packed sand at 70 k/ph can put some serious heat in them at times....plus the fact they are Coopers !!   

They have the biggest advertising budget ( and have done for yrs ), which means they have got a good market share, but it's well known they are a very ordinary tyre......just ask a tyre shop anywhere in the outback !!

There are people who will defend them till the cows come home, because they haven't had problems with them, but if you took a survey, they would be by far the most complained about tyre out there !!

Interesting the cooper is not a premium tyre in the us, but here in oz it is, ETD have certainly got a good marketing budget! Whilst I have not had coopers a close mate has and they developed bulges in the sidewall and 2 blew out, can't remember what ones tho but were a bit older.

You either love coopers or hate them!

Cheers

[jr]

Might also be good of problem tyres ply rating was indicated