Cooper Discoverer S/T Maxx

[SSF556]

Considering they are listed as 53lbs online, I'm actually impressed that they came in under that number. Weird thing is, their listed weight for a 255/80/17 E rates is 51lbs....

A lot of the sizes seem to weight less than a KM2 or toyo open county MT so I'm happy about that.

I see the duratrac in the same size is only 40lbs, wow, big difference. But that probably explains why I've seen so many people tear them apart off road.

The 255/75/17 DT is a P rated tire.....which is why there is a significant weight difference.

I currently have the 265/70/17C DT on my WK and it weighed in at 47 pounds.....

So going from a 2ply to a 3ply I am happy with the weight on the ST Maxx.


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[Hilldweller]

Luckie is a good dog.

 

[Fritzoc]

Have put the S/T Maxx to the test in the 8 inches of snow we got. I'm extremely impressed. I've owned many all wheel and 4 WD cars and trucks over 30 years. Many with snow tires for winter. I have to say, the Coopers mated to the JKU makes for the most impressive combination yet. Tracks straight. No wheel spin. plows though the snow with ease. Fantastic.

 

[kmacafee]

I put the 235/85/16 's on my Tacoma a few months ago and they are amazing in the snow and ice in Minnesota. Loaded up my camper, aired them down to 35 and drove the Mojave Road from Avi Casino to Kelso. Lots of deep sand, rocks etc -- never any issues. Quieter on the highway than BFG's and amazing traction and driveability. And cheaper than the BFG's.

 

[gwittman]

Did I read right that you air down to 35. That is higher than what I air up to on the road.

 

[doubleroses]

I air mine to 32 all around on my 2013 Tacoma. The ride is much better. I found that at 35-37 it's extremely stiff.

 

[Fritzoc]

What's the impact on your gas mileage at 32 vs 35-37?

 

[Redline]

What's the impact on your gas mileage at 32 vs 35-37?

A controlled back-to-back test would be needed to give relevant data... My guess is very little, if any noteable or repeatable difference would be found, as 32 psi is likely not under inflated for his load, and the diffenrce between 32-37 is not huge.

But tire pressures can be like religion...

 

[Robert Bills]

I experimented with air pressures between 32 and 38 psi on my Nissan Xterra, and currently run my LT265/75R16 ST/Maxx tires at 35 psi. I have not recorded any detectable change in fuel mileage between 35 and 38 psi.

 

[Redline]

I air mine to 32 all around on my 2013 Tacoma. The ride is much better. I found that at 35-37 it's extremely stiff.

x2

Within reason, as long as there is adaquate/appropriate psi, I find the impact of a few pounds of extra pressure primarily negatively affects ride and traction.

 

[gwittman]

A few pounds of extra pressure can also affect uniformity of tire wear. I typically run 33-34 psi front and 31-32 psi rear on the road and get good wear across the tires. Off-road I air down around 25 psi depending on trail conditions and the load I am carrying. I have not run under 20 psi but have been told many times that under 18 psi is more beneficial. I just can't get myself to go that low.

 

[Robert Bills]

I experimented with air pressures between 32 and 38 psi on my Nissan Xterra, and currently run my LT265/75R16 ST/Maxx tires at 35 psi.

A few pounds of extra pressure can also affect uniformity of tire wear. . . .

Very true. My experimentation with tire pressures, which included running the "chalk test" for even tire wear, let me to conclude that 35 psi was the optimum tire pressure for my rig

. . . Off-road I air down around 25 psi depending on trail conditions and the load I am carrying. I have not run under 20 psi but have been told many times that under 18 psi is more beneficial. I just can't get myself to go that low.

Based on the stiffness of the sidewalls of the ST/Maxx, I think 25 psi is too much pressure offroad for anything other than a gravel surface. Try 18 psi; you won't pop a bead. I regularly run mine at 18 psi offroad, but will go down to 16 psi on my next trip to try that out. (I used to run the 35" BFG MT tires on my Jeep at 12 psi and had no problems, and those were "C" load rated with more compliant sidewalls.)

 

[gwittman]

Usually when I am off-road, it is on an extended trip and I am carrying a significant load of supplies and gear. At 25 psi I am beginning to get significant sidewall bulge. I will go down lower when the trail gets pretty rough but at 20 psi I feel like going any less increases the risk of sidewall damage from pointy rocks. I will continue to experiment but I like to stay on the safer side of danger.
When I first started 4 wheeling in the late 70s with a FJ55 Landcruiser, I didn't air down at all off-road. I never had any problems but I am sure I could have had more traction and a better ride but it did stop me. I just kept going not know I was not doing it the best way.

 

[austintaco]

Just an anecdotal story, but on the back side of Golden Spike, I had to run the same obstacle two days in a row. The first time, I had about 20 psi, and I had to use my winch after multiple attempts. The 2nd day (we had to go back out in reverse and recover a broken down rig), I went with 15 psi. I crawled over the same obstacle in one attempt. It was amazing. BTW, this was with BFG KM, not Coopers.

 

[Kuduhunter]

Just put a set of 265/70/17 Cooper ST Maxx on my 1999 4Runner 3.4 limited. First impressions are very good. Dry pavement great with no break in time needed. No pulling to the right like had read in some posts.tracked straight. Currently have the psi at 33 psi. Rides good so will leave where it is. Made it up the hill in 12" of snow which I could not with the worn Cooper ADP's that they replaced. Drove it on snow packed roads today and handled just like on dry pavement. Did slide a few inches when tried on snow covered ice but not enough to worry about.
They are heavier but don't tell a lot difference in power loss but of course the 3.4 is not a powerhouse anyway. Am glad I did the tundra front disc brake upgrade first so have the extra breaking power for the heavier tires. Will keep track of the mpg the next several weeks to see how that was effected

The last thing is they look awesome. Was going with the GY Duratracs till read about all the sidewall issues and for now am glad chose the ST Maxx. Will keep updating as get more miles on them.