BFGoodrich KM3 vs Cooper ST Maxx

KM3 is mud terrain while ST Maxx is an all-terrain tire. Both the tires provide commendable performance in different areas.

KM3 provides good traction in deep mud due to its open tread design while ST Maxx offers excellent grip on ice all due to its stud holes and efficient sipes.

Want to know which tire has better grip on snow and rocks? Let’s find out.

Comparing KM3 and St Maxx

KM3 has an aggressive look. It has bold tread blocks placed in between numerous wide grooves. Its shoulder blocks are placed far apart from each other, much wide spaces are in between them. The spaces between shoulder blocks have long and bold stone ejectors placed in between them.

KM3 on road

Every second shoulder block has a cut, and all the lugs have sharp edges. Central part has similar shaped blocks placed all around, blocks are placed in pairs, separated by a narrow groove. Triangular shaped stone ejectors are also placed in between the central blocks. No sipe is found in the pattern of this tire.

ST offers a compact tread design. Compared with its whole pattern the shoulder grooves are the widest. Small stone ejectors are running between the shoulder blocks. Lugs have sharp edges with a sipe and a stud hole on each lug.

Cooper Discoverer ST-MAXX

Central part has two types of blocks, small and big. Blocks are placed in a sequence of three and two. Big blocks have two sipes while smaller ones have one sipe placed on them. Central part has numerous grooves dividing the blocks but they are narrower compared to the shoulder grooves.

On Road Comparison

In terms of on road traction the clear winner is St Maxx. As it is an All-terrain tire and is made to perform both on road and off road. It has comparatively compact tread design which allows more of the tire’s tread to come in contact with the road. Due to this the grip is enhanced and the vehicle can confidently move at high speeds. When it comes to on road wet traction this tire again beats its counterpart due to more contact patch and numerous sipes, which help to wipe away the water. This tire is also good at resisting hydroplaning due to its deep grooves and interconnected grooves channel.

KM3 has an open tread pattern and this does not help it to move on road confidently. As the wide and open grooves decrease its contact patch and this in result decreases its grip. In terms of wet traction this tire again is behind its opponent as due to less contact area and absence of sipes. Although it is the champ when it comes to countering hydroplaning this is because of its open tread, which has plenty of space for the water to pass from it. The wide grooves help to throw the water backwards, helping the tire to maintain grip with the road in flooded conditions.

Off Road Comparison

Mud Terrain

Mud terrain is one of the harshest areas that any tire has to face and KM3 is made to tackle such grounds. Due to the wide grooves of KM3 tire, it is no issue for it to move in muddy areas as these open grooves grab the chunks of mud and throw them backwards, clearing the way of the tire and helping the vehicle to move forward. Even in the deep muddy areas the wide grooves of this tire come in handy and you never have to worry about getting stuck in muddy swamps.

St Maxx gives good performance in muddy areas due to its deep grooves but as it has narrower gooves compared with its competitor so it lacks behind it. But still, it performs pretty well in light to medium muddy conditions and your vehicle won’t get stuck but if you take the risk of going in deep mud with these tires on board, then you can get in trouble. As relatively narrower grooves aren’t able to tackle heavy muddy swamps and most probably the tire will get stuck. In the case of mud, KM3 is the clear winner due to its open tread pattern.

Snowy Area

Light snow is considered same as mud, so the criteria to judge a tire’s performance is also the same. KM3 will perform pretty well in light snow due to its open tread design. Its grooves will help the tire to hold and throw the mud particles in a backward direction, enabling the tire to move forward. But if we talk about ice then the results are opposite as wide grooves don’t help in icy areas. The more the contact patch the more grip on ice. So as KM3 lacks good contact patch so it won’t be able to grip properly on ice and the chances of slipping will increase.

On the other hand, St Maxx due to its deep grooves also performs well on soft snow but due to its compact tread design comparatively, it will not give a satisfactory performance. You can use it on areas with minimum snow but taking it in deep snow can be problematic. Although it is not as good on snow as its competitor, but on ice it performs much better due to its higher contact area with the ground that increases the grip and helps the vehicle to move without slipping. It also offers stud holes to provide extra traction on ice.

Rocky Terrain

For any tire to move smoothly on rocks or pebbles, it needs to have open tread, to have biting edges and numerous bold stone ejectors. So as both of these things are available in KM3, it will perform pretty well on the rocky areas. As we have discussed earlier about the open tread of KM3 so we wont detail here. Its open tread provides biting edges which help the vehicle to climb on rocks. Moreover, it has bold stone ejectors as well, long and bold ejectors are placed between its shoulder blocks while triangular shaped emitters are placed in between its central tread blocks. These stone/pebble ejectors emit the rocks, stones or pebbles from getting stuck into the grooves.

If we talk about St Maxx, it also has stone ejectors that do not allow any particles of rocks or stones to get stuck into the grooves. But this tire has compact design and due to this, it lacks the biting ability, this hinders the tires climbing motion and breaks the momentum of the vehicle. So, to conclude we can say that from both the tires, KM3 is a clear winner in rocky terrain due to its stone ejection ability and open tread pattern.

Comfort Differences

Noise is the main thing to consider while talking about comfort. A tire with open tread pattern will produce more noise as it has much space for the air particles to be trapped inside and collide with the tread blocks. This collision produces noise and more it is, the more noise will be produced. As KM3 has much more wide grooves than its competitor so it will produce more noise while moving on road. While if we discuss off road comfort then KM3 is way better than its peer that’s because its open tread helps to absorb jerks and it works as a second suspension for the vehicle.

Cooper tire due to its closed tread pattern will produce less noise while travelling on road as the air particles won’t find more space in its tread. While on an off-road drive, this tire won’t be much comfortable comparatively, as its closed pattern isn’t able to absorb much jerks and it feels like a rigid tire, making the journey jerky, comparatively.

Durability of both tires

Both tires are made up of durable and tough material. KM3 uses CoreGard Max race proven technology that makes its sidewall much tougher compared to its counterpart. It comes with extreme sidewall protection and its tread is made up of chip and cut resistance technology which makes it perform even better in rocky terrains. As it has less contact patch so that’s why its tread wear is also less comparatively, and company offers 6 years warranty for defects from workmanship and the life of usable tread.

ST is also made from hard material. It has Armor Tek3 construction, tread is made up of 3 ply walls which enhances the durability of the tire while providing extra side wall protection. Its material is puncture resistance as well and will minimize the punctures in harsh terrains.


  • KM3 is mud terrain and ST Maxx is an all-terrain tire.
  • KM3 performs well on mud due to its open tread pattern.
  • On ice, ST grips better while on snow KM3 is the winner.
  • KM3 has much better traction on rocks.
  • ST provides more comfort on road and KM3 offers better comfort off road.
  • ST Maxx is costlier than its rival.

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