Cooper Discoverer ST Maxx vs BF Goodrich KO2

Cooper Discoverer ST Maxx and the BF Goodrich KO2 are all-terrain tires capable of delivering a powerful off-road traction with a smooth ride on the road. But which one comes out on top when compared side-by-side? Let me make things easier for you.

With a wealth of experience and knowledge in tire engineering, in my opinion, the BF Goodrich KO2 features a superior traction on both wet and dry roads, though it’s wet traction can be improved still. Moreover, the tire provides better fuel and tread economy as well, and it’s ride quietness and winter traction really impresses you. Off-road, although it provides superb grip on rocks, it cant outperform the Cooper ST Maxx. This tire is provides superior mud, sand and gravely terrain performance as well. And on-roads, surprisingly, you get a better bumps absorption abilities with it, as well.

Available Sizes

The BFG KO2 has 90 total sizes now, and these sizes come in 15 to 22 inches. Besides that, these sizes have the following specs.

• Speed Ratings: R, S, or Q
• Load ratings: C to E
• Weight range: 35 lbs to 67 lbs
• Tread Depth: 15/32″ on all sizes
• Winter ratings: M+S & 3PMSF
• 50k miles warranty

Review KO2 here.

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

(Make sure you know, how to read tire sizes).

Tread Structure

Starting with the Cooper Discoverer ST Maxx, the tire being the rugged-terrain gives you a more aggressive structure with asymmetric tread design.

I personally really like how good the tire’s tread is at self cleaning all the loose off-road stuff, where A/T tires mostly get stuck (such as sand, and mud).

This feature is given to this tire by the placement of the central lugs.

If you consider the image, you’d note that these blocks in the middle although have interconnected grooves, they make lateral orientation of these tread voids connecting with the outer vertical channels (from where shoulder voids get linked).

In contact with any loose surface, the smaller lugs with sharp edges and notches break down the particles as they move out through these lateral grooves away from the tire. Moreover, these tread voids are also embedded with multiple stone ejectors in between, so any dirt particles trying to get lodged are thrown away.

And where these lugs provide off-road traction, they are not so bad when it comes to directional grip on roads as well. Though the same can’t be said about the lateral grip, which depends on the shoulders as those lugs are very wildly spaced apart.

With such aggressive design of these studable lugs forming stone ejectors in between and outer sharp edges with sidewall lugs, the tire is only able to do things better when it comes to rugged terrains.

On the other side, you get a slightly less “rugged” tire with BF Goodrich KO2.

This tire 3 worm shaped lugs in the middle creating a web of grooves (of interlocking formation).

All these lugs offer good enough traction on both on and off-road tracks.

On pavements, their consistent design account for good enough on-road manners. Whereas with full depth notches and siping, which split open the lugs all the way (depending on the type of surface) allow for amazing off-road traction.

(Though on thing to note about these sipes is that they can do a little better on wet roads).

Moving towards the shoulders, you get a more aggressive pattern of lugs, making wider gaps in between with bold stone ejectors.

Actually the tire yields dual stone ejectors, the conventional ones are between shoulder lugs as mentioned, whereas the others, which are shaped as triangular, are strategically place in the outer circumferential channels.

Moreover, these shoulder blocks have full depth notches and similar (to the middle) siping design.

And adding to the overall aggressiveness is their outer edges, which have thick mud scoops because of staggered structure and bulky sidewall lugs which providing epic grabbing abilities under lowered air pressure.

Durability

Out of both tire, although it would make more sense if the Cooper ST Maxx, being a hybrid tire, to be more durable. That’s really not the case.

The tire only features a similar internal construction, (if not weaker) in comparison. It consisting of 3 ply polyester casing, and 2 steel belts, covered with a nylon cap ply.

BF Goodrich KO2 on the flip side, has 3 ply polyester, twin belts, and 2 cap plies of nylon which are also spirally wound.

Recommended Read –
Are A/T tires harder to puncture: https://tiredriver.com/are-all-terrain-tires-harder-to-puncture/

Wet Road Traction

The overall tire’s wet traction depends on it’s ability to clear water off form the tread. And that is done by 3 main features, siping, grooves, and tread flexibility.

A majority of water gets channeled out with the help of tread voids, or grooves. And both tire’s they are plenty, so there no problem with it comes to hydroplaning (which can also be considered as floating of a tire on water, since with this water layer comes in between the tread and the ground, losing traction).

The left over water gets dealt with sipes, which if “flexible” enough to move, create suction for the water particles, and they get cleared that way.

So although you get a softer tread on Cooper Discoverer ST Maxx, the lacking sipes on it’s tread still account for limited wet traction compared to KO2.

Though keep in mind, that the BF Goodrich KO2 with it’s stiffer composition is also a great tire for wet roads, despite having a lot more siping, comparatively.

Performance on Streets

In order to accurately assess the dry performance of an all-terrain tire, one must consider directional traction, steering, and handling ability. And that’s exactly what I am doing here.

Directional Grip

Directional grip tells the tire’s performance on highways, where you mostly run straight. And, as this grip gets calculated with braking and accelerating efficacy, the middle portion of the tread (being the central point for the weight), caters to most of it.

That’s why with such wide lateral tread voids on Cooper Discoverer ST Maxx, you get shorter braking distances (during testing).

Whereas the BF Goodrich KO2 allocates more rubber to road meetup, and it’s meshed (groove) design ensure a better stability as well, when moving at higher speeds.

(That’s why you get better speed ratings on this tire, in comparison, as well).

Lateral Traction

As the Cooper Discoverer ST Maxx comes in rugged terrain category, where it gets a hybrid shoulder design resembling those seen mostly on mud-terrain tires, its not surprising to see it’s lacking performance when it comes to handling.

BF Goodrich KO2 on the other side, although is also pretty rugged on shoulder too, it’s still gets to provide much better handling efficacy, thanks to it’s sporty steering response.

Steering Response

The critical performance metric of steering sensitivity or communication is often overlooked, though it has a crucial impact on a vehicle’s handling.

It depends on the tire’s maneuverability and is judged by the rubber-to-road connection quality. Let me explain.

The Cooper Discoverer ST Maxx basically features a softer tread, and with more tread depth combined with weight, the lugs want to flex/bend more. This results in tire over and under-steering, and so you get a slower steering feedback.

BF Goodrich KO2 on the other side, with its dual compound, with harder overall built provides better foundational support to the lugs, and they don’t want to stick to the surface too much while turning.

Moreover, as I mentioned in the durability section, despite having more plies under the hood, the tire’s lighter weight accounts for better over and under-steering balance.

Fuel Usage

Fuel usage is dependent on the rolling resistance of the tires, and the weight and tread composition of the tire are the two key factors determining it. Although off-road tire designs may not perform well in fuel efficiency, it’s still necessary to understand their performance for long-term benefits.

Cooper Discoverer ST Maxx is although very similar in terms of weight, it’s balder design still accounts for each lug bearing more pressure on it. And so its tread rubs off the surface with a greater force.

In other words, its tread is stickier towards the ground, and consumes more fuel as a result.

BF Goodrich KO2 has firmer lugs in comparison, and so they don’t want to flex a lot, which wastes energy of the fuel.

Tread Noise

The source of noise generation is the flow of air, predominantly through the shoulder grooves of the tire’s tread. This air basically strikes the tread walls, and produces what we call “tread noise”.

And so with a more voided structure, the Cooper Discoverer ST Maxx becomes louder evidently.

BF Goodrich KO2 on the other side, although is pretty bald towards the shoulders, it still very quite for it’s design. This has to do with its’ superb pitch sequencing technology.

The tire very subtly changes it’s lugs geometry throughout the tread, so that air particles hitting each of these could create different tones, and those can cancel out each other to dampen the overall noise.

Snow Traction

Out of both tires, the BF Goodrich KO2 provides better overall traction on snowy terrains (mostly hard packed snow).

The tire has a lot more siping, and that combined with it’s numerous notches, and hook shaped lug design, you get a better snow grabbing abilities, allowing the tire to have 3 peak mountain snowflake rating unlike the Discoverer ST Maxx.

The Cooper ST Maxx on the other side, is although lacking in comparison, it’s still not a bad tire, considering it comes in rugged terrain category. And I do like the fact that its lugs are stud-able.

Traction Off Road

The challenges of off-road terrains can be diverse, with mud being particularly tough and requiring specialized tires, while gravel and dirt roads can be navigated easily. That’s why I’ve chosen to talk about each terrain separately.

Mud Traction

The challenge of handling mud with all-terrain tires can be addressed through a tire with self-cleaning grooves and a more aggressive tread pattern. This will provide improved traction and stability in muddy conditions.

Cooper Discoverer ST Maxx is no wonder a superior tire for muddy terrains, being in the rugged terrain category. The tire features much wider grooves, with more tread depth, so much greater volume of mud escapes out.

Whereas on BF Goodrich KO2, the interlocking closed up tread voids are more susceptible to getting packed up.

Recommended Read –
Are A/T tires good in mud? : https://tiredriver.com/are-all-terrain-tires-good-on-mud/

Rock Climbing

Rocky terrains demand a lot of durability and biters (which help in both lateral and longitudinal climbing).

And both of these tires with 3 ply sidewalls, and powerful gripers providing amazing traction values.

Cooper Discoverer ST Maxx although features bigger groove mouth, grabbing the surface of the rocks in both vertical and horizontal angles, it’s sidewall lugs and shoulders are still not as aggressive in comparison.

BF Goodrich KO2 on the other side, may lack wider grooves, it makes up for it with it’s lugs on sides, which work at their maximum potential with lowered air pressure.

On Sand

To have a stable grip on sand, reducing the air pressure of your tire is a must. This leads to a “floating” effect and improved performance on such softer surfaces.

Though, the tire’s structure and tread composition are additional factors that also impact the overall performance, that’s why the Cooper Discoverer ST Maxx with a softer tread, and outer edges provide better traction abilities.

BF Goodrich KO2, on the other hand, suffers, due to it’s spirally wound cap plies, which makes it’s sidewalls and shoulders stiffer, and more prone to digging (which is a recipe of getting stuck on sand).

On Gravel and Dirt

For a smooth ride on gravely roads, it’s important to have off-road tires with self-cleaning grooves. Tires lacking stone ejectors, even those with a cut-resistant rubber composition, can get clogged with dirt and stones, affecting traction and increasing the chances of harm.

That’s why both of these tires here are doing so great.

The Cooper Discoverer ST Maxx with such wider grooves and an open design is very rejecting to any kind of debris, and in comparison, although the BF Goodrich KO2 features tightly packed up lugs, the dual stone ejectors helps the tire a lot, in a similar manner.

Summary

In summary, the Cooper Discoverer ST Maxx is a better tire if you are mostly staying off-road, though it’s durability is almost the same as the KO2.

BF Goodrich KO2 on the other hand, is great with dry and wet roads, where it’s wet traction is just marginally better (it needs improvement, given it’s less aggressive design).

Moreover, it also provides better winter traction, fuel usage, and tread life.