Kelly TSR vs. Cooper ST/MAXX Results

[telemike]

Stopped by tire dealer today and compared the Kelly TSR and Cooper ST/Maxx. The stack of Cooper was taller than the Kelly's side by side. Coopers have a wider track. The Kelly's have 6 ply tread, 2 ply sidewall. Flexible and bead area was like a normal tire. The Coopers have 7 tread ply and sidewall are 3 ply. The Coopers have a super thick bead area. The Coopers are way way way heavier! Super Beefy. MPG killers. The Kelly's were lighter.

The Cooper sidewalls were stiffer and thicker than the Kelly. The Kelly tread had larger void area and looked good for mud and rocks. The Cooper is less void, but still looks very good for dual purpose duty.

Which to get? That is still the question. Kelly might be better off-road at the expense of tough sidewalls and carcass. Cooper is an expedition tire, looks like it will get you across no man's land and back.

 

[08SolarFlareH3]

I would go with the Coopers. If they are anything like the old S/T you will be very happy based on what you were looking for in your other thread. Plus 3 ply side wall is a huge plus.


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[cgalpha08]

I dont have the coopers your looking at i have the at/3's and i am very pleased. Only thing they suck at is mud haha

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[telemike]

I am leaning towards the Kelly. I want to keep some mpg's for daily driving . Other internet reviews on the Kelly are favorable. Maybe if I had space to have a second set of tires and wheels for offroad..... I could do a beeier tire.

I am worried about gas mileage being horrible with heavy tires. O need to be able to afford to get to the trail.

 

[f5moab]

Stopped by tire dealer today and compared the Kelly TSR and Cooper ST/Maxx. The stack of Cooper was taller than the Kelly's side by side. Coopers have a wider track. The Kelly's have 6 ply tread, 2 ply sidewall. Flexible and bead area was like a normal tire. The Coopers have 7 tread ply and sidewall are 3 ply. The Coopers have a super thick bead area. The Coopers are way way way heavier! Super Beefy. MPG killers. The Kelly's were lighter.

The Cooper sidewalls were stiffer and thicker than the Kelly. The Kelly tread had larger void area and looked good for mud and rocks. The Cooper is less void, but still looks very good for dual purpose duty.

Which to get? That is still the question. Kelly might be better off-road at the expense of tough sidewalls and carcass. Cooper is an expedition tire, looks like it will get you across no man's land and back.

Kelly's will have better wet and snow traction due to the greater number of sipes in the tread blocks (but mostly in the outer blocks). Coopers will be a lot tougher on a rocky trail with the 3 ply sidewalls. If you are not going to do any serious off road in rocky areas, then I would go with the Kelly's. Just my opinion though.

 

[Pappibri]

I agree.. If your not going to be playing on alot of rocks then go with the lighter tire.. If it is your daily driver and want it to have a decent ride still. The kellys will ride better I am sure..:thumbs:

 

[telemike]

I will only be doing an off-road trip about every 1-2 months. I guess the Cooper would make more sense if I had to go off-road once a week and needed that durabilty and toughness. It sure weighs a lot!

I spent hours Googling and bing-ing both tires and reading user reviews on forums all over the place and both got great reviews. The kelly seems to do good in mud and gets good road manners too.

The Kelly TSR is going to be the best compromise for me in the real world. The goodyear Duratrac's run about $200 more a set so those are out.

 

[Hunner]

You have to consider you are comparing an 8 ply tire to a 10 ply tire.
ST/MAXX 61 lbs. 285 75 16
Kelly 58 lbs. 285 75 16
3 less pounds per tire won't get you much more mpg even times 5 or a total of 15 less lbs. on the lighter constructed tire.
Keep us posted on your choice.

 

[telemike]

Are you sure about the weights? The Cooper seemed about 10 lbs more to me side by side.

 

[OtterH3]

Any weight you add to rotational mass of the drive train will make a noticeable difference in mpg. Putting a 5lb dumbell in the truck wont make a difference, but adding more weight or drag to the wheels and/or tires will and the drive train has to work harder to propel said mass. A little weight can make a noticeable difference. I come from the drag racing circuit where we used crazy expensive once piece wheels and ran nitrogen to reduce rotational mass to help et's. If you can even save 1lb per corner it helps a lot and Ive seen guys do crazy things to achieve much less.

 

[telemike]

From what the internet says:

ST/maxx = 61 #
TSR = 59.4 #

in person though, the Cooper felt a lot heavier than the TSR........

I can't freakin' pick which one to get! I don't want to make a $1,000 mistake.

:gaah:

 

[Hunner]

From what the internet says:

ST/maxx = 61 #
TSR = 59.4 #

in person though, the Cooper felt a lot heavier than the TSR........
I can't freakin' pick which one to get! I don't want to make a $1,000 mistake.

:gaah:

I just looked at some tire sites to get those lbs. Could be some variables but your numbers are even less difference. I just wanted to point that out. You are the only one that can decide based on your use. Ha ha it's supposed to be fun!

 

[Hunner]

Any weight you add to rotational mass of the drive train will make a noticeable difference in mpg. Putting a 5lb dumbell in the truck wont make a difference, but adding more weight or drag to the wheels and/or tires will and the drive train has to work harder to propel said mass. A little weight can make a noticeable difference. I come from the drag racing circuit where we used crazy expensive once piece wheels and ran nitrogen to reduce rotational mass to help et's. If you can even save 1lb per corner it helps a lot and Ive seen guys do crazy things to achieve much less.

Yeah I come from and still am involved in road course racing, turn both ways and up and down hill sweeping turns and fabrication but we are talking about a rolling brick here where small differences are hard to define. In the big scheme of things in multiple use driving in an H3, I think that little difference considering all the variables in calculating mpg as opposed to a timing trap in a straight line on a track would be even harder to define.
Comparing the two similar 285 size tires it is a fine line. Jump to 315's and compare that to a 285 and size does start to matter.
The ST/MAXX is 32.9 inch and the Kelly 33 inch in the 285 size.

 

[telemike]

All things considered, I had my heart set on the Cooper based on durabilty and reviews. The kelly does have thinner and more flexible sidewalls and a smaller bead protection area. The weight made me second guess the choice. Both get good reviews across the forums.......


:gaah:

 

[alrock]

Thin sidewalls are a bad, bad thing if you wheel anywhere with rocks or sharp branches. When I had the base 265 P rated tires I very quickly shredded three of them. A strong sidewall is a much better financial benefit than the minor mpg increase you might realize with lighter tires. I doubt you'll see a $250 fuel savings but you could easily see a $250 savings by not replacing one tire. I have cut tires on both rocks and sharp tree/shrub stumps.

 

[OtterH3]

A vehicle's fuel economy is the direct result of its total resistance to movement. This includes overcoming inertia (Newton's Law), driveline friction, road grades, tire rolling resistance and air drag. In order to offer the same level of performance, heavy vehiclesrequire more power (and more fuel) than light vehicles. All-wheel and four-wheel drive vehicles require more power than two-wheel drive vehicles and boxy vehicles require more power than low drag aerodynamic vehicles.
But how much influence does each of these elements have and when are their influences felt? Once you eliminate the fuel converted into heat by the engine, the relative percent of influence that these other factors represent during stop-and-go city driving are very different then during steady-speed, highway driving.
During stop-and-go city driving, it's estimated that overcoming inertia is responsible for about 35% of the vehicle's resistance. Driveline friction is about 45%; air drag is about 5% and tire rolling resistance is about 15%.
Overcoming inertia no longer plays an appreciable role in the vehicle's resistance during steady speed highway driving. For those conditions it is estimated that driveline friction is about 15%; air drag is about 60% and tire rolling resistance represent about 25%.
Let's explore a scenario where a high performance replacement radial tire has a whopping 20% increase in rolling resistance over a low rolling resistance Original Equipment standard passenger radial. To calculate the potential change in mpg resulting from using the high performance tires in place of the Original Equipment tires, we would multiply the tire's percentage of influence on the vehicle's overall resistance (15% in the city and 25% on the highway) times the high performance tires' 20% increase in rolling resistance.
If the vehicle equipped with standard Original Equipment, low rolling resistance passenger tires normally provided 25 mpg in the city and 30 mpg on the highway, installing tires with 20% greater rolling resistance would only drop fuel mileage by a calculated 3% (to 24.25 mpg) in the city and a calculated 5% (to 28.5 mpg) on the highway. While this is a measurable difference, it probably isn't much more of an influence on real world fuel economy than being stuck in rush hour traffic a couple of times a week or being stopped at every red light instead of continuing through a string of green lights.
The easiest way to reduce rolling resistance to enhance fuel economy is to make certain that the tires are properly inflated. A vehicle that requires its tires to be inflated to 35 psi (based on the vehicle's tire placard) will have an increase in rolling resistance of approximately 12.5% if the tires are allowed to become underinflated to just 28 psi. Therefore, maintaining the vehicle manufacturer's pressure recommended for light load and heavy load conditions may almost be as important as the tires being used. So in short, it wont make a huge difference unless we start talking about significant differences in weight.

 

[telemike]

:emb:

I will let y'all know what I bought on Saturday. 70/30 weighted towards Coopers now. Will see if dealer can weigh the two and see what the difference will be.

 

[08SolarFlareH3]

With the larger voids of the Kelly there might be an increase in rolling resistance then the Cooper with the tighter tread pattern. I don't think the difference in weight or rolling resistance of the two is going to make a significant difference.


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[telemike]

Checking tireack, the Duratrac weigh 56 lbs, about 5 less than Cooper. Stock Bridgestones are listed at 51 lbs.

 

[f5moab]

You have to consider you are comparing an 8 ply tire to a 10 ply tire.
ST/MAXX 61 lbs. 285 75 16
Kelly 58 lbs. 285 75 16
3 less pounds per tire won't get you much more mpg even times 5 or a total of 15 less lbs. on the lighter constructed tire.
Keep us posted on your choice.

Someone may rate the cooper as 10 ply but it is an eight ply tire. The three sidewall plies are part of the carcass that is also under the tread. From Cooper's site:

"Cooper's proven, class-leading 3-ply “Armor-Tek[SUP]3®[/SUP]” construction contributes to the durability of the S/T MAXX by adding strength to the sidewall and tread area."

Then they add two more polys, two steel and one nylon to the tread cap. So the five added to the tread cap, plus the three ply carcass, equals 8 ply.

Many moons ago, it took 10 plies to make a E rated tire; however, with the invention of new high tech compounds, E rated can less than 10 and usually seven or eight. (Maybe even less as new compounds come on the market.)

Telemike: Just remember, one time off road on sharp sidewall biting tires, could make the difference between three ply vs. two ply sidewalls.

 

[f5moab]

A vehicle's fuel economy is the direct result of its total resistance to movement. This includes overcoming inertia (Newton's Law), driveline friction, road grades, tire rolling resistance and air drag. In order to offer the same level of performance, heavy vehiclesrequire more power (and more fuel) than light vehicles. All-wheel and four-wheel drive vehicles require more power than two-wheel drive vehicles and boxy vehicles require more power than low drag aerodynamic vehicles.
But how much influence does each of these elements have and when are their influences felt? Once you eliminate the fuel converted into heat by the engine, the relative percent of influence that these other factors represent during stop-and-go city driving are very different then during steady-speed, highway driving.
During stop-and-go city driving, it's estimated that overcoming inertia is responsible for about 35% of the vehicle's resistance. Driveline friction is about 45%; air drag is about 5% and tire rolling resistance is about 15%.
Overcoming inertia no longer plays an appreciable role in the vehicle's resistance during steady speed highway driving. For those conditions it is estimated that driveline friction is about 15%; air drag is about 60% and tire rolling resistance represent about 25%.
Let's explore a scenario where a high performance replacement radial tire has a whopping 20% increase in rolling resistance over a low rolling resistance Original Equipment standard passenger radial. To calculate the potential change in mpg resulting from using the high performance tires in place of the Original Equipment tires, we would multiply the tire's percentage of influence on the vehicle's overall resistance (15% in the city and 25% on the highway) times the high performance tires' 20% increase in rolling resistance.
If the vehicle equipped with standard Original Equipment, low rolling resistance passenger tires normally provided 25 mpg in the city and 30 mpg on the highway, installing tires with 20% greater rolling resistance would only drop fuel mileage by a calculated 3% (to 24.25 mpg) in the city and a calculated 5% (to 28.5 mpg) on the highway. While this is a measurable difference, it probably isn't much more of an influence on real world fuel economy than being stuck in rush hour traffic a couple of times a week or being stopped at every red light instead of continuing through a string of green lights.
The easiest way to reduce rolling resistance to enhance fuel economy is to make certain that the tires are properly inflated. A vehicle that requires its tires to be inflated to 35 psi (based on the vehicle's tire placard) will have an increase in rolling resistance of approximately 12.5% if the tires are allowed to become underinflated to just 28 psi. Therefore, maintaining the vehicle manufacturer's pressure recommended for light load and heavy load conditions may almost be as important as the tires being used. So in short, it wont make a huge difference unless we start talking about significant differences in weight.

Do people actually calculate fuel mileage on a Hummer?:giggle:

 

[telemike]

With Uwharrie's rocks, the Cooper is the safer choice. I do like the Kelly tread pattern better.

 

[telemike]

Went with the Kelly TSR. It seems to be be the best tire for my H3 and for what I plan to do. Just riding around town they are fairly quiet and smooth riding.

 

[Happy Hummer]

GooooooooooooD Choice! I was quietly hoping you'd pick the Kelly....
My bro had them on his Wrangler and they went damn near forever...
Chris

 

[Gunner_45]

Any issues getting them to balance them out?

Use very much weight?