Both the Cooper Discoverer ST Maxx and the Nitto Ridge Grappler feature new silica tread compound, combined with water evacuating channels and biting edges (on the treads), giving dependable off-road performance. These tires offer a great option for compact, 1/2 – and 1-ton trucks and full sized SUVs. Let’s see how they perform next to each other.
Being a tire engineer, from my perspective, Cooper Discoverer ST Maxx although shows equal mud traction, it’s a better snow tire, shows superior comfort, and does great on roads, when things are wet. On the other side, the Nitto Ridge does better on dry roads, in terms of traction, fuel, tread wear and noise, and off-road it shines on rocks and sandy dunes.
Review Nitto Ridge Grappler here.
Table of Contents
Sizes Available
The Nitto Ridge Grappler offers 98 total sizes, in 16 to 24 inches, with following specs:
- Load ratings available: SL, XL, D, E and F.
- Speed ratings available: T or Q.
- Weight range : 36 lbs to 91 lbs.
- Tread depth range: 13/32″ to 18/32″ (Most common: 16.4/32″).
- Sizes have no mileage warranty or 3PMSFR.
On the other side, the Cooper Discoverer ST Maxx comes in 47 total sizes in 15 to 20 inches. They have following specs:
- Speed ratings: Only Q.
- Load ratings: C to F.
- Weight range: 38 to 70 lbs.
- Tread depth: 18.5/32″ on all.
- No 3PMSF ratings available.
- No treadwear warranty.
Tread Structure
I don’t think the amazing design of Nitto Ridge Grappler would ever grow old.
The tire simply gives out a very aggressive look with its 4 triangular ribs in the middle section.
Two of these have notches facing the grooves of the shoulder lugs, and the other two are aligned vertically, carrying all the rest of the features, like sharp razor-shaped edges, off-sets, and full depth siping.
All these prominent features basically help the tire a lot on all kind of off-road terrains. And it does that, without compromising a lot on smooth pavements, as all lugs are backed by reinforced foundational supports, adding highway stability.
Together all these lugs in the center form X and Z shapes of grooves providing amazing self cleaning capabilities.
Moving over the shoulders, the lugs here although don’t render notches, they still carry full depth sipes in them, have bolder ejectors in their lateral tread voids, and on the outer margins are staggered.
So they get to be pretty biting, still. And further adding to that, are it’s dual sidewalls, (different sidewall pattern on each side of the tire, where you get to choose, which side to show out). And on both, the tire features chunkier lugs in comparison.
Let’s move towards the Cooper Discoverer ST Maxx.
So here you get to see 2 sets of blocks making lateral slanted grooves joining the outer equally wide circumferential channels.
Due to the lateral orientation of these lugs, the tire gives out a paddling effect off-road, especially on loose terrains such as snow, sand and mud, as they are able to clear out form the tread very quickly.
The smaller lugs placed in the middle of various proportions provide the necessary biters, while these grooves with built in stone ejectors escape the dirt/mud out very quickly.
Moving towards the shoulders, you get bigger lugs, with slightly more aggressive design, having chamfered edges, stepped sides and thicker interlocking sipes.
The wider spacing they make also have bold stone ejectors in between.
And towards outer margins, they make semi-serrated shoulders (basically each lug is staggered on itself). And with that you get powerful sidewall biters which cater to amazing traction with lowered air pressure.
Tire Toughness
The durability of off-road tires is an essential consideration in providing satisfactory performance on rough terrain (where tire goes through a lot of “sharp” encounters).
To meet this requirement, a majority of these tires feature cut-resistant rubber, deep tread voids, and robust internal construction (which is the main one).
That’s why both of these tires show up with similar toughness overall, with their 3 ply polyester covers, having twin belts made of steel, on top, which are then further covered with 2 more layers of nylon fibers.
Wet Traction
A tire’s wet grip is dependent on its ability to effectively remove water from the contact patch, improving grip and reducing hydroplaning risk (the two factors on wet performance).
Let me talk about them separately.
Hydroplaning
A tire that is unable to evacuate water from its tread quick enough, can lead to dangerous phenomenon of aquaplaning or hydroplaning, where the tire floats on top of the water losing all gripping capabilities.
But that’s hardly the case with hybrid tires, where you get to have very wide grooves to channel water out in time.
That’s why both of these tires do great here. Their web of tread voids provide clear pathways for water to leave out efficiently, though, the little water that’s left behind, coming directly underneath the lugs, is the most problematic (which gives you the wet grip).
Wet Grip
Wet grip is achieved with sipes, which are tiny slits on the tread, soaking water particles in them by flexing and creating a negative pressure difference.
That’s why with a harder composition, the Nitto Ridge Grappler does not allow it’s sipes to mold enough, limiting it’s suction abilities.
The Cooper Discoverer ST Maxx on the other side, not only features a better silica density, enabling flexibility to it’s tread, but you also get more tread depth (on average), so sipes are able to suck in more volume of water to provide better grip.
Dry Traction
There are two main key areas to consider when it comes to dry traction, directional grip and lateral traction. And in both the Nitto Ridge Grappler provides a better job.
The directional grip depends on the central potion of the tread (and how much contact it makes with the ground, while rolling straight). And so Nitto Ridge, with closed up lugs arrangement there, results in shorter braking distances.
Moreover, it’s shoulders lugs are also less spaced apart as well, and during cornering as these lugs get to bear the most weight on them, the Cooper with it’s limited connecting abilities lack here overall.
But most of the handling traction comes form it’s faster steering response. The tire has a stiffer composition and it makes a much firmer contact with the ground.
Are All-Terrain Tires Good For Daily Driving? : https://tiredriver.com/are-all-terrain-tires-good-for-daily-driving/
Fuel Usage and Tread Wear
As the tire rotates, it compresses and rebounds, which creates friction between the tire and the road. This friction generates heat and consumes energy, which translates to fuel consumption.
That’s why even though the Cooper ST Maxx is lighter in weight, it’s softer compound still molds more with the ground, reducing overall fuel efficiency.
The Nitto Ridge Grappler on the other side, with it’s harder compound and less tread depth (on average) would not flex as much in comparison.
Moreover, with a stiffer composition, the tire also exhibits slower rubber wear as well, whereas Cooper ST Maxx, even though has a lighter structure, it’s softer compound (and wider grooves) are still susceptible to faster burning.
Though the tire doesn’t come with any tread wear warranty just like the Nitto Ridge.
Ride Quality
Two crucial factors in ride quality are tire tread noise and the tire’s capacity to soak up road imperfections via its structure and tread. I’ll go into more detail.
Tread Noise
Noise gets generated by the flow of air (which comes in, mostly through the shoulder grooves, and hits the walls of the tread).
That’s why the Cooper Discoverer ST Maxx with wider shoulder voids, allow air particles to have a greater impact on the walls of the tread, creating unwanted noise waves.
Nitto Ridge Grappler on the other side, not only has packed up outer lugs, but the tire also deals with the rest of the noise with better pitch sequencing, which it calls “variable pitch technology”.
Here, with vigorous angles of the lugs, it cuts down the noise by creating different tones, which cancel out each other.
On-Road Vibrations
The Cooper ST Maxx although is louder comparatively, it does provide better effectiveness in reducing road imperfections.
This is because the tire gets to have a softer composition, which although suffers when it comes to fuel, provides better settling of the bumps.
So one might say, its comfort, literally comes at a price.
In comparison, the Nitto Ridge Grappler although offers a more stable ride in comparison, it’s stiffer compound would not settle the vibrations of the road as effectively as the Cooper.
Winter Traction
Both tires are not going to impress you here, but still, out of them, you’d find Cooper Discoverer ST Maxx to be more gripping.
The tire features snow vices in its outer circumferential grooves, which hang on to the fluffy snow in a better way, and it’s softer compound helps flex it’s notches (with more ease) providing the needed bite. (Moreover, its softer compound also bears winter temperatures, for longer, without freezing).
On the other side, the Nitto Ridge Grappler features a wider section width, where you need a skinnier tire on this terrain. And with it’s tread more susceptibility to getting frozen up quicker in comparison, its overall winter performance gets limited.
Furthermore, although both tires bring very poor traction on ice, at least you get stud-able lugs on Discoverer ST Maxx, allowing this tire to have better gripping capabilities on hard packed terrains as well.
Are A/T tires good in Snow: https://tiredriver.com/are-all-terrain-tires-good-in-snow/
Off Road Capabilities
Off-road terrains can present different difficulties, with mud being particularly challenging and needing specialized tires, while gravel and dirt roads can be handled with ease. That’s why I’ve decided to go over all of them one by one.
On Mud Terrains
In muddy conditions, less aggressive tires may struggle to evacuate mud due to their narrow grooves, leading to reduced traction and packing.
Though in case of these two boys here, that’s not really the case, as they both come in rugged terrain category, having mud-terrain like shoulder blocks, (where their central lugs stay all-terrain, that’s why they are hybrid).
And comparing both, you can’t really put one over the other. This is because the Cooper Discoverer ST Maxx although provides better mud escaping though its slightly wider shoulder voids, its skinnier sidewall lugs don’t provide the “paddling”, which is also very important for traction.
The Nitto Ridge on the other side, has narrower grooves comparatively, but its dual sidewall design, with thicker lugs, and wider mud scoops on staggered shoulders renders superior paddling, throwing thick clay backwards, and generating forward moving inertia with.
So overall, I am going to rate both of these tires equal.
On Rocky Trails
A tire that can handle rocky terrain must have a tread that provides traction, flexibility, and durability.
And although durability wise, both tires are equal, the Cooper Discoverer ST Maxx gets to have an upper hand in with its pliable tread blocks biting in to the rocky surface with greater force. And with wider grooves, they yield a better groove mouth as well, whereas the full depth notches and siping hugs the surface like a champ.
Though this only goes if you don’t lower the air pressure on this tire, as it’s missing with “thick enough” sidewall lugs, and that’s where the Nitto Ridge Grappler comes in with its dual sidewall pattern, with chunkier biters on both.
And with lowered PSI values, they paste their lugs out, and sticking to the rocky surface like a magnet. So overall its a win for Nitto Ridge.
My Guide on Air Pressure: https://tiredriver.com/air-pressure-guide-for-all-terrain-tires/
On Sandy Dunes
Lowering of the air pressure of your tire is a must, on sand. This is because it created floating effect on the ground. And so that’s why tires with larger section width, lighter weight and a softer compound do better.
Having said that, the Cooper Discoverer ST Maxx being lighter in weight, and having a more pliable tread with softer edges although provides amazing traction, with lowered air pressure, it does not enhance that grip as much as the Nitto Ridge Grappler.
This is because Ridge Grappler supplies much better sidewall lugs, which are spread out more in comparison, and with lowered air pressure thy are able to provide much better floating abilities with enhanced footprint meeting the sand.
Lastly
Cooper Discoverer ST Maxx although is slightly more voided, it’s mud traction is on par compared to it’s counterpart. Other than that, the tire yields better traction on snow, comfort, and on-roads, its a better tire to have on wet roads (though overall, comapred to other options available, it’s not so great).
The Nitto Ridge Grappler on the other side, is overall a better tire to have on dry roads, as it’s great with traction, noise, fuel and tread economy. And off-road you’d get a better performance on sand and of course rocks, where it shines the most.
(I rated this tire for rock traction, in my list of top all-terrain tires).
