Tyre Topic: Cooper Discoverer S/T Maxx

[nj swb]

This Tyre Topic is for members to post about Cooper Discoverer S/T Maxx. Post your thoughts on grip, noise, wear, airing down, or anything else you consider of interest to other members.

Cooper Discoverer S/T Maxx.



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[nj swb]

I've had these tyres on my NJ (in 285/75-16) and my NT (in 265/70-17), and would happily have them again.

They're definitely at the aggressive end of the all terrain spectrum, and I found them noisier / more intrusive on the NT than they were on the NJ, but I've always been happy to put up with a little noise for decent off-road tyres. Conversations at 110km/h are not an issue.

Off road, I thought they were great. All the grip I need, bearing in mind that I hate mud and avoid it wherever I can - so I have no idea how they rate as a mud tyre. They love to dig in sand, so tyre pressures are more important than with some less aggressive tyres, but once the tyre pressures are right they perform really well.

On road, other than the noise factor, I have no complaints. I thought they hung on well in both wet and dry, I never had any concerns.

[old Jack]

I have been running the ST Maxx LT245/75R16 10 ply since 2011.
I changed the tyres over on the Challenger straight out of the showroom so I do not have any comparison on the Challenger.
On the 3rd set, first and second set changed out at around 70,000kms each, but I do change tyres when they are down to 3-5mm in total tread depth. I did a 4 and 1/2 tyre rotation so 9 tyres over 143,000kms. This time round I went narrower by 10mm and increased the diameter by 38mm so LT235/85R16 10 ply. Factory tyre size is 265/70R16.

In theory (my theory anyway!) these should be better off road but I have not done any serious off-roading on the new size to prove it either way. I have not noticed any detrimental handling characteristics either on bitumen or on good dirt roads, wet ot dry, since I went to a narrower tyre.

The ST Maxx are not a tyre for those that like a quiet smooth tyre, these are a tyre best suited for extra heavy duty off road outback touring duties but the strength and reliability comes at a price at purchase and extra fuel consumption, tyre noise, tyres need rotation every 7500kms to keep them "quiet".

They are an aggressive AT/mild MT hybrid so great for outback touring but if the High Country was my backyard I would be running full mud tyres, not that the ST Maxx are bad in the mud, in fact they are better than most AT's.

Similar hybrid AT/MT tyres that other forum members who I travel with have or had,
Mickey Thompson ATZ P3, same caracass and compound but slightly more aggressive tread but less effective stone ejectors.
Kumho MT 51, similar carcass but softer compound and shoulder/upper sidewall, and from other peoples experiences only get 2/3 to 3/4 of the life of the ST Maxx or ATZ P3 but the MT51's are cheaper by $50 to $75 a tyre.

OJ.

[Pwoffey]

I have had 2 sets of Cooper ST/MAXX LT265/65/R17 120Q Load Range E. I still have the second set on and I estimate each set lasts about 50-55k. This involves at least 75% driving on long trips, usually towing a camper-trailer. A lot of that is on gravel roads or worse.

There is no doubt the tyres are noisy (certainly compared to the OEM highway tyres and even the Bridgestone D697s that I tried early on in my ownership), but we just get used to it and it doesn't bother us. I can't comment authoritatively on performance in the wet on bitumen, because those conditions rarely happen where I live and where I have traveled to. Given the right tyre pressures (and of course this is the key factor), performance on gravel, rock, slippery mud, and even sand is outstanding. But what I like best is the strength both of the deep tread and the side-walls. I have yet to have a puncture on tens of thousands of kilometers of nasty tracks or on gravel roads or the blacktop. Touch wood. Mind you, it's just as well they are so puncture resistant because they are bloody heavy to wrangle.

Of course one person's experience is mere anecdote, not evidence, and I might be unlucky enough to get a puncture or punctures tomorrow. But for my particular needs, when it comes time to replace I will almost certainly go with the ST/MAXX again.

[old Jack]

I have just fitted the 4th set of ST Maxx to my PB Challenger, I have previously had 2 sets of LT245/75R16 and both these sets of tyres were changed after about 70,000kms when the tread depth was down to about 3mm to 5mm above the tread wear indicators because this is what I chose to do for safety and reliability. The 3rd set I used were LT235/85R16 since Auto Mate fixed the auto trans programing issues. I choose this size because I wanted taller and narrower tyre than either 265/70 factory size or 245/75 size I had been running since the Challenger was new.

Unfortunately I only got 35,000kms out of a 4 tyre rotation with the LT235/85R16, this is because the wheel alignment was poor and the front tyres developed excessive heel and toe wear after 5,000kms so I swapped the rears to the front and the same happened again, I should have taken it in for another wheel alignment but I thought I could manage the tyre wear by rotations as the steering tracked fine and had no balance vibration issues. WRONG!

Even though the tyres had been run at 32 to 34psi cold front and rear, and the tyres had heal and toe wear on the outer edge the tyres still wore more in the middle of the tread indicating over inflation. Centre tread depth was down to about 1mm above the tyre wear indicators so still legal but the tyres lacked wet weather grip especially around corners on the front wheels. I did have to get through a nasty mud bog the other week and was impressed with mud traction even on very worn tyres, so the sidebitters and offset outer tread lugs do work well. The steering wheel was offset to the left by about an 1/8 of a turn and I thought thought that was related to when I had paddle shifters fitted but I was WRONG again.

I had a Central Australia trip planned for June and went to fit new tyres beforehand only to be told there was a 3 month wait! I did locate 5x ST Maxx in LT235/85R16 in Alice Springs so my plan was to buy a new set in Alice springs as they had stock and put them on hold for me. The trip got delayed due to COVID lockdown then finally cancelled when I injured me knee so I have just got the new tyres on now. I used a different Tyrepower this time around and fitted the same LT235/85R16 ST Maxx, the wheel alignment was way out and corrected so the steering wheel is now straight, steering is lighter, there is less bump steer and hopefully I will get a longer life out of this set if I take care of them!

I have reduced cold inflation pressures down to 30psi and will monitor wear, at the moment this seems about right as I am getting a 6psi presure rise between cold and hot tyre temperatures after about 45 minutes of driving around town. This weekend I have a 500km trip planned, about 400km on bitumen so I will see how the tyre pressures change, I have an internal TPMS fitted so this is an easy task.

OJ.