Cooper ST Maxx?

[cwdtmmrs]

JaSAn, I just installed a set of 31/10.5/15 on my Toyota and they are at least as quiet as my old BFG KO's, if not a bit quieter. I've only got a bit over 100 miles on them, but on my truck they absolutely ride and stop better than the BFG's did. I do notice a slight bit of over steer, but my camper is off right now and that might change with it installed again. FWIW, I wanted a 3 ply sidewall as well and that narrows tire choices down to a 3-4 contenders. Even that is deceptive, because some 2 ply tires use 2 plies of 1500 denier polyester and the BFG has 3 plies of 1000 denier polyester. Goodyear has a 3 ply with 2 plies of 1000 denier polyester and 1 ply of Kevlar, and the most expensive I checked. Cooper S/T Maxx has a 3 ply sidewall with 2 plies of 1500 denier polyester and the 3rd ply is 1000 polyester on a bias for added strength. They have a LOT of tread as well. Only miles will tell if I made the right choice. The important thing to remember is different brands/sizes/types/rigs all perform differently. Too bad you cannot test drive tires before buying.

MANXMAN, Go to any tire's spec page and check the RPM, revolutions per mile, and work backwards from there to get the true diameter.

cwd

 

[OpenSpace]

I just had a set of 305x70R18 (35 x 12.5) installed. Happy with them thus far. We have a business fleet of 40-plus vehicles and an account with Discount. I know the guys there, and they love the BFG AT, but not on full-size trucks. So, I was looking at the Toyo R/T, the Nitto Ridge Grappler, and the Cooper ST Maxx. Discount recommended any of the 3. The ST checked all the boxes. I've had it in all conditions already with about 1500 miles on it. May be a bit louder than my BFG ATs on the 4Runner, but too many variables to say - entirely different rigs. I recommend the STs.

 

[Vic Harder]

I have read these tires are actually slightly taller than their size would indicate. Has anyone who has them found that to be true?

Would really like to try these tires, but they are not offered in 265/70 18 (32.6") that I want to continue running. If they are a little taller than their 275/70 17 size would indicate, (32.2") they might be really close. I have a set of 17" rims so no problem switching. Don't want to go wider than 275 though.

Some tire companies have "tire size comparison" tools. This one does: http://www.1010tires.com/Tools/Tire-Size-Calculator

Here are the two sizes you were looking at:

The tire specs are here - http://ca.coopertire.com/Tires/Light-Truck/Discoverer-S-T-MAXX.aspx

According to that chart, the 275/70-17 are 32.17" in diameter.

Close enough?

 

[cwdtmmrs]

Vic... I am surprised at you as much as you analyze things! If you want to be accurate, take the revolutions per mile and work backwards to the true diameter. Or just compare revolutions per mile from tire to tire. It is the only true way to tell tire diameter.

cwd

 

[Bill D]

Vic... I am surprised at you as much as you analyze things! If you want to be accurate, take the revolutions per mile and work backwards to the true diameter. Or just compare revolutions per mile from tire to tire. It is the only true way to tell tire diameter.

cwd

How is the revolutions per mile calculated?
My guess would be... by measuring the diameter.

 

[cwdtmmrs]

Bill, your guess would be wrong. If you look at the tire #2 in the chart that Vic posted, you will see that the stated diameter is 32.16" and the calculated diameter off of the revolutions per mile is 31.19". That is 1' difference in real world use. Tire diameters are almost never as the mfg claims.

cwd

 

[Bill D]

Based on the information I posted below, I would not use the revolutions per mile to calculate tire diameter. Nor would I use the tire diameter to calculate the revolutions per mile.

That being said diameter is diameter. I wasn't aware that tire manufacturers were misquoting such a simple measurement.


Revolutions Per Mile
Revolutions per mile indicates the number of times a tire revolves while it covers the distance of one mile. Depending on the tire manufacturer, revolutions per mile may be either measured in a laboratory or derived from calculations based on their previous test experience.
Tire revolutions per mile cannot be calculated by simple math because the tire tread and sidewall bend and stretch (deflect) when the load of the vehicle presses the tire against the road.
Since the resulting loaded or rolling radius is less than half the tire's published overall diameter (which would only reflect the tire's unloaded radius), calculating the tire's absolute rolling circumference isn't possible.
Additionally, a tire transitions from an unloaded to loaded state as it rolls, continuously flattening where the tread footprint comes into contact with the road. These continuous transitions result in some tread slippage, again increasing the tire revolutions per mile beyond what simple math would indicate.

 

[cwdtmmrs]

Bill, I knew all of that. My point is that the only way to compare tire to tire is by the revolutions per mile if you want your gearing and speedometer to remain unchanged. The tire will never almost never measure advertised diameter.

cwd

 

[Vic Harder]

not only that, they wear down too.

 

[Squatch]

How noisy is the ST Maxx on the highway? The Ram is my daily driver and I have to drive 500 to 1500 miles to get to the Mountain West. And I like quiet.

jim

I've done a couple of long highway drives with these now. You will hear the tires. These are a very aggressive tread. Next step is a full on Mud Terrain. These are much more aggressive than most any AT. But that being said they are surprisingly quiet. No where near the hum of some of the MT's I've run over the years. But you will know they are there. Compared to a similar size BFG it's simply a different sound and maybe a tad louder. Think the kind of sound tires make on wet pavement. Kind of a whirring sound. I hear them but don't find them intrusive at all. But I have a very quiet truck cab.

If you want P metric or highway tread quiet these aren't them.

 

[Squatch]

I'm getting close to 10k miles on these tires. They are mostly used on the highway for long trips. I've done at least 4 trips of +or- 2,000 miles so far and a bit of gravel roads and hauling stuff on soft ground around the property.

No complaints. I'd buy them again tomorrow. Can't say I even notice the tires on the road anymore. Just part of the sound of driving and my truck is pretty quiet anyway. Traction in the wet or in mud has been very good. They feel rock solid on the road when towing.

After the next trip I'll rotate them. Probably overdue now. but not seeing any signs of adverse wear or much of any wear for than matter!

 

[mitch h]

I have at3 s on our 1/2 chevy for close to 50,000 miles now and they still have tons of tread on them. Mostly highway use. Works well in snow and rain. Good tire . Mitch

 

[buckland]

I also have the Cooper AT3 E and before that the C. I like them a lot but do not have as good a tread left after 25000. I think as I live rural most our roads are dirt or bad up hill and down on beat up gravel/oil that they just wear out fast (all brands). I do like the traction both in snow and wet. I will get another set when these go.

 

[Squatch]

I've run BFG AT KO's for years. Great tire. But anyone that thinks they are too loud is ready to sell their truck and buy a luxury car.

 

[Cayuse]

I got close to 50,000 from my AT3's on the Tundra, always carrying the Grandby. They still had a moderate amount of tread left when I went to the ST Maxx last February but with a month long southwest trip in the offing that was going to include Tuweep and the White Rim Trail I wanted a newer tire and something with a beefier carcass. I've got about 12,000 miles on them so far and they've been great, yes there is some noise but there's noise hauling a camper around too.