Review: Cooper Tire Discoverer STT

Review: Cooper Tire Discoverer STT

Get Toyota Cruisers & Trucks Magazine on the App Storedownload_nowFrom air up to air down, your tire purchase can be a major component of any truck build.  We recently teamed up with Cooper Tire and FN Wheels to put the Cooper Discoverer STT to the test and see how it handled all of our overlanding needs.  After nearly 10,000 miles over a variety of terrain, the Discoverer STT has handled every test given to it with ease.  

Cooper Tire Review Toyota Tacoma

Since the first day the Cooper STTs were mounted on the FN Wheels Five Stars, I knew this was going to be a good relationship.  The STT has an aggressive look that really stands out with the matte bronze finish on the unique Five Star wheels.  The first matter at hand was to ensure proper fitment within my wheel wells for the larger 315/75R16 tires.  Measuring only 11.9” wide, they were a great option as I had previously cleared for 305/70R17 tires which measured 12” wide.


Exploring the Colorado and Utah backcountry are my preferred ways to spend my weekend, however, my truck is still my daily driver during the week.  For such an aggressive tread design, I was blown away by how relatively quiet they were along the roads.  Yes they still had a hum to them, but compared to other mud terrains out there, they were more along the lines of an aggressive all-terrain as far as on road manners are concerned.  

Our first real test was a five day overland trip down to Coyote Buttes and Vermillion Cliffs in Arizona.  If you have ever travelled in the Vermillion Cliffs Wilderness, you know how sandy these roads can get back there.  It was rare that we needed 4wd with the STTs pushing our way through.  Numerous times I would push my luck by slowing down and seeing how well I could work through deep sandy areas in 2wd.  I would lock up the rear and the STTs would just keep digging their way through the sand pushing me through.  Only time I really needed 4wd was to get out of our camping spot at the White Pockets.  The exit is a steep hill climb with deep sand that serves as a “gatekeeper” to this camping location.  I was hoping for more of a challenge getting up the hill after hearing previous trip reports, but I was able to get up fairly easily.  For those reading this on their iPad app, see below for a video.  

Cooper Tire Moab Toyota Tacoma

After having fun in the sandy roads of the Vermillion Cliffs region, we turned our truck north into the Grand Staircase on our way north to the San Rafael Swell.  Cottonwood Canyon Rd. cuts through the Staircase and is a fairly maintained dirt road cutting north which allowed us to keep a good pace when we weren’t stopping to take photos in the amazing scenery.  Upon entering the San Rafael Swell, we were greeted by some heavy rain.  The rain passed, but it left some sloppy, muddy roads for the remaining portion of our trip.  The STTs had no issues finding traction on the slick roads cutting through the canyons and valleys.  

A couple weeks later, we found ourselves on another five day overland trip, but this time to the Moab region.  We made up a modified Kokopelli journey into Moab as we ventured into the Lost Spring Canyon, Winter Camp Ridge and through Dome Plateau on our way to Dewey Bridge where we picked up Kokopelli proper.  This portion of the trip was filled with more sandy roads cutting through the backside of Arches National Park.  It wasn’t until we took the Top of the World trail that we encountered our first rock crawling tests for the STTs.  Many times I approached ledges expecting to have to work a little to get up them, but the STT’s scalloped shoulder lugs had no issues grabbing a hold of the rock and pulling the truck up (see the video below).  The tire’s ability to grab onto the rocks also helps greatly coming down large ledges, allowing controlled drops.  

Cooper Tires Test on Toyota Tacoma

The Discoverer STT’s “Armor-Tek3” carcass construction features two radial polyester body plies and one angled polyester body ply to provide three full plies of protection.  Along with a raised rim protector, the STT offers some trail security when encountering hazards that would normally damage other tires.  This was helpful when descending Rose Garden Hill.  With many ledges to drop down and odd shaped rocks trying to cut into your sidewall, the STTs showed no signs of damage through this section and formed nicely around the rocks allowing a very controlled descent.  

After conquering the many ledges found along Top of the World, Kokopelli and Rose Garden Hill, the smoother slick rock of Seven Mile Rim was a welcome sight and offered a different set of challenges.  Here, the gripping power of the STTs was able to shine.  Sure there are other mud terrain tires with more grip, but with the stickier compounds, you sacrifice tread life.  The STTs showed plenty of grip on the slick rock helping make quick work of even the hardest lines found along Seven Mile Rim.   

So far my experiences over the past two months with the Cooper Discoverer STTs have been very enjoyable and I am very pleased with the results.  We’ll see how the long-term results are with the STTs, but as of right now, I would not hesitate to put another set on my truck.

Summary of my observations:

  • Icy/snow pack – They had better grip than other mud terrains I’ve tried.  They won’t perform as good as some mud/snow tires, but under most conditions, grip was never an issue.  When aired down, these have amazing grip through deep snow.  The deep shoulder lugs really grab the snow well.  
  • Rain – I had no complaints or traction issues even in heavy rain.
  • Rocks – Aired down, they would wrap around the rocks extremely well.  The Armor-Tek3 carcass really held up great against the rocks and trees we encountered.  
  • Mud – These love to paddle their way through mud and clean out well.  
  • Sand – We saw a lot of sand in Southern Utah and Northern Arizona and we had no problems during our travels.  Plenty of response when needed to get through the deep sand.  However, with that much grip, don’t get too throttle happy in the deep stuff.  
  • Tread Life: I am happy to report that after 9-10,000 miles through the mountains of Colorado and exploring the backcountry of Utah and Arizona, the STTs are only down to approximately 17/32nd tread depth (20/32nd depth new).

Cooper Discoverer STT
Size Tested: LT315/75R16
Testing PSI: Road @ 34-35psi, Off-road @ 15-18psi
Load Range: E
Approved Rim Width: 8”-11”
Load Capacity/Tire: 3860lbs
Overall Diameter: 34.49”
Section Width: 11.9”
Tread Depth: 20/32nd
Weight/Tire: 65lbs
Price as tested: $290/ea

Wheel Spec:
Manufacturer: FN Wheels
Model: Five Star
Dimensions: 16”x8”
Bolt Pattern: 6x139.7mm
Offset: -25mm
Backspacing: 3.52”
Weight: 18.9lbs
Load Rating: 2,100+ lbs (955kg)
Price as tested: $775/set of four

For more information on Cooper Tire and their extensive line up of tires, visit their website, and follow them on Facebook.  

For more information on the Five Star and other products offered by FN Wheels, please visit them at and follow them on Facebook.


  All Photos!

[flickr set=72157646588952050]


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