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Cooper Stt Pro vs Toyo Open Country MT

Cooper Stt Pro vs Toyo Open Country MT: Both of these tires are mud terrain and are made to perform off road. Both have open and aggressive tread design. Cooper Stt Pro has better mud evacuation abilities while Toyo MT takes the lead on icy tracks.

Stt Pro has more void ratio so it can move through mud and sand without any trouble. It has bold stone emitters which help it to move confidently on rocky tracks. While its counterpart, Toyo MT also performs pretty well on all kinds of terrains, giving it a tough competition.

We have tested both these tires on different terrains, moved them on harsh roads and carefully noted the abilities of each tire.

Both these tires are very strong competitors and it isn’t easy to choose between them but still we have seen Stt outperforming the other tire in many areas but with a very little margin. Let’s discuss all the points further in detail!

Side By Side Comparison

Cooper Discoverer STT Pro

Cooper Discoverer STT Pro

Toyo M/T

Toyo M/T
 Stt ProToyo MT
Tire typeMud-terrainMud-terrain
UsageOff-road, all-weatherOff-road, all-weather
 Mountain snowflake ratings (3PMSF)yesyes
Tested size31X10.50R15LT31X10.50R15LT
Tread depth2019.1
Section width10.7’’10.7’’
Maximum load capacity2270lbs2270lbs
Load/ speed rating109Q109Q

STT Pro has higher void ratio than its counterpart. The grooves of this tire are wider and it also has more tread depth. Tread blocks are big in size but are scarcely placed all over the tread.

STT Pro Close Up
STT pro sidewalls, and central area.

The shoulders have two types of lugs, one is longer and other is shorter with almost same width. The larger shoulder block has a wide dent on its corner and a small zigzag sipe is also placed on it.

Central part has differently shaped tread blocks with some having sharp edges while others have round corners. Half of the blocks in central part are placed in pairs with a narrow sipe dividing them.

This tire has long and bold stone ejectors placed in between its shoulders and some emitters are also placed in the central part in the group of three, one after another.

Toyo MT
Toyo MT

Toyo Open Country MT has a rib like structure and all the blocks are longitudinal in shape.

Overall, its void ratio and tread depth is less than that of its rival but still it has huge spaces in between the tread blocks.

All the shoulder lugs are of same shape and are long in length. Every second shoulder block is having a dent on its outer side and all of them have a long single sipe running on them.

The blocks in the central part are placed in two rows. All the tread blocks are hook shaped with sharp edges and have only one sipe on them.

Stone ejectors are only placed between shoulder lugs and they are also not as long and bold as of its competitor.

On Road Dry Traction

Well, for a tire to be good on road, it must have higher contact patch and as both of these tires are mud terrain so they lack this property.

But Toyo has comparatively lower void ratio so it has higher contact patch and so in terms of on road dry traction it will perform relatively good.

Cooper Discoverer Stt Pro has an open tread design with very less contact patch so that’s why it has smaller footprint and bad on road dry traction.

The shoulders of this tire are also open providing less tread blocks to be in contact with the road so as a result its handling is not good, on the road.

 Stt ProToyo MT
Dry on-road GripVery LowLow
Dry on-road handlingVery LowLow

On Road Wet Traction

Toyo MT has a relatively higher on road wet traction due to its higher contact patch and better siping.

It is comparatively better in terms of wet grip and handling compared with Cooper Discoverer STT Pro.

Stt Pro has very small contact area and small sipes so it isn’t able to perform satisfactorily in wet conditions while on road.

But as both of these tires have higher void ratio so they are equally good at resisting hydroplaning cause water is thrown back with the help of deep and wide grooves, maintaining the contact of the tire with road.

 Stt ProToyo MT
Wet on-road GripLowModerate
Wet on-road handlingLowModerate
Aquaplaning resistanceHighHigh

Off-Road Traction Comparison

 Stt ProToyo MT
Mud tractionExtremely HighHigh
Snow tractionExtremely HighHigh
Ice tractionLowModerate
Rock tractionExtremely HighModerate to High

Mud Terrain

Stt Pro performs extremely well in muddy areas all due to its higher void ratio with deep tread.

The wide grooves of this tire help it to move through mud by evacuating the mud easily as the spaces between tread blocks are higher so the mud particles can be easily thrown backwards enabling the tire to accelerate forward.

This tire can be taken in any sort of deep mud puddles and it won’t be a problem for it to move through them. The large spaces between its shoulder blocks help the tire while cornering and minimize the chances of getting stuck.

Toyo MT, on the other hand is also good at mud terrains because of its big grooves and directional tread pattern. This tire also throws the mud particles backwards with the help of its wide grooves but as it has relatively less void ratio so it can’t compete with its counterpart’s performance.

It can also move through deep mud but should be carefully moved as due to its comparatively less void ratio it may stuck in deep mud puddles.

Snow Terrain

Soft snow is same as mud and requires same type of tire structure.

Cooper Discoverer Stt Pro again takes the lead due to its higher void ratio. The soft snow particles can be easily gripped and thrown back using wide grooves, which help the tire to move forward. But if we talk about its traction on ice then it is on the lower side as ice requires higher contact patch and more sipes and this tire lacks both properties so it is not recommended to use it on icy tracks, to avoid slipping.

Toyo MT also performs well on soft snow due to its open tread pattern but it lacks behind its counterpart due to relatively lower void ratio and low tread depth. It can move through light snow but it isn’t recommended to use it in deep snow, to avoid getting stuck.

On ice, this tire performs better than its rival due to a slightly bigger footprint that allows more of the tire’s area to come in contact with the ground and long sipes on tread blocks wipe away the water. But still this tire isn’t made to be used frequently on ice as its tread is open.

Rock Terrain

The more the void ratio the more biting ability a tire has on rocks as the STT has higher void ratio so it has better biting ability on rocks compared with its rival and this feature helps it to crawl smoothly.

Moreover, it has bold and long stone ejectors in its shoulder blocks and some emitters in the central part that emit the particles on rocks, stones or pebbles from getting stuck into the grooves. So, the tire moves smoothly on rocky areas.

As discussed before Toyo MT has lower void ratio compared with its rival so it has less biting ability on rocks and its grip is affected.

It also has very few stone ejectors that are only placed in between its shoulder blocks so its stone/pebbles emitting ability is also minimized and rock particles can damage its tread.

But as it has a little less tread depth than its rival so it has less space for the particles to get stuck into the grooves. In terms of rock traction, Stt is the winner but Toyo MT is also a good option.


In terms of on road comfort, the noise production of a tire is considered and, in this case, both the tires have almost equal space in their tread for the entrapment of air particles.

The air particles get trapped in the grooves and collide with walls, producing sound. Both of these tires produce almost equal sound while moving on highways with STT producing a little higher noise than its competitor.

In terms of off-road comfort Cooper Discoverer STT comes on top as due to its open void ratio the jerks are absorbed by the tire and it works as a second suspension for the vehicle giving the feel of a lesser inflated tire. Toyo also provides a comfier ride but lacks behind STT due to relatively lesser void ratio.

Durability And Treadwear

Toyo MT is constructed using tough polyester which results in its higher durability. Its treadwear is relatively higher due to its higher contact patch and less tread depth. Its rolling resistance is also higher which results in more fuel consumption.

Rock climber sidewall technology is used in STT Pro to make sidewall tough and durable moreover stone armor technology is also used to defend against rocks and pebbles. Its rubber compound is uniquely formulated for higher tread life.

It has less rolling resistance due to less contact patch and it also has higher tread depth, both of these factors result in its higher tread life cause treadwear is minimized.

 STT ProToyo MT
Treadwear mileage warrantyNo warranty
Uniformity warrantyFirst 2/32’’500 Miles

Quick Summary

Both of these are mud terrain tires.

Cooper Discoverer STT Pro…

  • Has better hydroplaning resistance ability.
  • Has better mud and snow traction.
  • Has better rock traction.
  • Has higher durability.
  • Provides better off road comfort.

Toyo MT…

  • Has better on road traction.
  • Has better ice traction.
  • Provides better on road comfort.
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