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Cooper Discoverer STT Pro Mud Terrain Review

Serious Traction in Any Condition

Corey Simone
Nov 13, 2015
Photographers: Corey Simone
When it comes to extreme traction for the most challenging off-road driving, almost nothing beats a mud-terrain. Cooper recently released its newest tire, the Discoverer STT Pro, which is the most traction-oriented in their line-up. We were given the opportunity to spend two days in the Colorado backcountry testing out the STT Pro on-and-off the highway and are happy to report that we couldn’t be happier.
Photo 2/15   |   Discoverer STT Pro Tread
The STT Pro is the replacement for Cooper’s departing, but very popular, Discoverer STT. The STT Pro sports a three-ply sidewall that features the company’s Armor-Tek3 protective ply. This ply in the sidewall runs 90 degrees to the first two, giving the tire increased strength and sidewall puncture resistance. The STT Pro has a hybrid tread pattern featuring a 3-2 inner tread rib pattern that works to reduce road noise while at the same time improving off-road traction.
Photo 3/15   |   Cooper Discoverer STT Pro Sidewall Flex On Rock
To further improve the tire’s performance on the trail, the tread features angled and grooved walls with raised rubber ribs at the base of each tread block, designed to reduce stone retention. The most unique new feature to the STT Pro is the inclusion of mud release dimples. The dimples run along the tire’s shoulder tread blocks and create air pockets that don’t allow mud to stay trapped, allowing for quicker and easier self-cleaning.
Photo 4/15   |   Cooper Discoverer STT Pro Ledge Descent
Common among off-road enthusiasts is airing down tires for the trail, and the STT Pro has that covered too. Side biter cleats, a flex groove, and a rubber rim flange protector all aid performance when the pressure gets low. The side biter cleats allow for improved traction when the tire is flexing against an obstacle, while the flex grove is a designed flex-point in the tire that improves ride performance by dampening uneven surfaces.
Photo 5/15   |   Testing Discoverer STT Pro On Jeep Wrangler On Muddy Trail
When the road gets wet, Silica-infused rubber compounds and variable-depth siping provide excellent traction as well as cut and chip resistance. The silica infused compound also improves braking distance.
Photo 6/15   |   Cooper Discoverer STT Pro Driving Through Mud
Our time behind the wheel was spent in the mud, on the trail, and on the highway. Overall, the STT Pro performed admirably in all situations. In the mud, the tires gave a feeling of stability and control, even when the mud was thick and sticky. When we took them over rocky ledges, they bit hard and failed to slip. On the highway, road noise was present but not nearly as loud as other mud-terrains we tested, and we could easily drive while having a conversation without needing to raise our voice. Though our time was short, the terrain was varied enough to prove to us that the Discoverer STT Pro is a great replacement to the outgoing STT, giving us the confidence to take on every obstacle that came our way.
Size Tested: 315/70R17
Type: Radial
Load Range: E
Maximum Load (lb @ psi): 3,195 @ 65
Sidewall Plies: 3 w/Armor-Tek Protective Ply
Approved Rim Width (in): 8-11
Tread Depth (in): 21/32
Section Width (in): 12.6
Overall Diameter (in): 34.57
Revolutions Per Mile: 600
Weight (lb): 66.6
Test Vehicle: ’07 Jeep Wrangler


Cooper Tire
Findlay, OH 45840