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Cooper Tire Discoverer A/T3 and S/TMAXX

During SEMA 2010, two new Cooper Tires caught the attention of 4X4REVIEW.COM on Day 1 of our annual coverage.  The new Cooper Discoverer A/T3, replacing the Discoverer ATR, and the new Cooper Discoverer S/TMAXX eventually replacing the Discoverer STT would be worth a closer look. 

Cooper Tire Ride-N-Drive
Cooper Tire invited 4X4REVIEW.COM to their Tire & Vehicle Test Center to put these new tires through their paces.  This 1,000 acre test facility located 50 miles south of San Antonio is equipped with wet and dry road handling courses as well as off-road testing facilities including rock gardens, hill-climbs, mud-bogs and miles of various trail types.  Cooper Tire uses this and their indoor test facilities to put Cooper product offerings through their paces before those tires are made available to the consumer. 

Cooper Discoverer A/T3

Cooper TireAll-Traction, All-Terrain, All-The-Time is the basis for the A/T3 signature on the newest all-terrain-type tire from Cooper Tire.  This tire, released to dealers in February, 2011 is designed to replace the Cooper Discoverer ATR and go up against recognized all-terrain tire competitors.  The A/T3 is currently available in 30 SUV sizes and 32 light truck sizes, ranging from 15 to 20 inch rim diameter and providing:
• Superior wet & dry traction and handling
• Outstanding cut-n-chip resistance
• Enhanced off-road durability and treadwear

The Cooper Discoverer A/T3 would be compared to two competitive products, the Toyo A/T Open Country and the well regarded BFGoodrich All-Terrain T/A KO.  Each tire was mounted on identical Chevrolet Silverado crew-cab pick-ups.  All tires LT265/70R17, aired to the same level.


All Terrain Tire Tests

First up, wet-handling…
Cooper Tire unleashed us on a water soaked autocross course to test wet-weather acceleration, braking, turn-in and high-speed maneuvers.  Each tire would be tested on the Cooper Tire Wet Vehicle Dynamics Area (VDA), a massive 14-acre square of asphalt flooded with a steady ¼” deep stream of water. 

Test 1 – Toyo A/T Open Country 
Cooper Tire was wise to put us in this tire first as it set an easy-to-beat baseline.  As much as I would like to share positive results, the Toyo did not perform well in the wet.  This tire accelerated and braked adequately but lost traction during cornering and high-speed maneuvers.  Essentially this tire rolled over and understeered, through all but the lowest speed corners.
Test 2 – BFGoodrich All-Terrain T/A KO radials 
For any off-roaders not trapped under a rock for the past decade you will recognize the brand name, raised white lettering and characteristic tread pattern of the T/A.  These are THE tires that come to mind when considering All-Terrain radials.  The BFGs bettered the Toyos in acceleration, braking, cornering and high-speed maneuvers.  When the tires began to slip they were easy to pull back into control.  A definite seat-of-the pants step up from the Toyos.
Test 3 – Cooper Discoverer A/T3
Having just tested the BFGs I would be reviewing the Coopers with a critical mind.  Heavy on the gas up the first straight and hard on the brakes before the first corner.  Result, the tires stuck!  Next a reducing radius sweeper that sent the Toyo-equipped truck into the cones like a bowling ball in a ten-pin lane.  Result, even less push than the BFGs!  I could actually feel the tire as they reached the edge of their grip and then work the throttle to keep the truck on course.  By my third lap on the Cooper Discoverer A/T3 tires I was sporting an ear-to-ear grin and the confidence of a rally driver.  These tires outperformed the Toyos and even the BFGs when pushed in the wet.

For fun, the Cooper Tire team also provided a pair of stock Jeep Wrangler TJ’s shod with Cooper Discoverer A/T3 tires for a run in the mud.  While not a dedicated mud-terrain tire, Cooper wanted to show the impressive mud-handling of the Cooper Discoverer A/T3.  Off I went into the bottomless mud-bog that Cooper had been flooding for days prior to the event.  To my amazement, the Cooper Discoverer A/T3 powered and carved through the mud like they were made to do so.  What is even more impressive is how well the Cooper Discoverer A/T3 tread pattern voided the mud clods after each run. 



Cooper Discoverer S/TMAXX

MAXX-Toughness, MAXX-Traction, No-Compromises are what Cooper Tire promises with the new Cooper Discoverer S/TMAXX.  This is a big set of promises for a tire that will replace the rugged Cooper Discoverer STT over the course of the next two years.  Set to launch in April, 2011, the Cooper Discoverer S/TMAXX will first be available in eight popular sizes including:

16″ Sizes
17″ Sizes 18″ Sizes


Cooper TireThe rugged Cooper Discoverer S/TMAXX is a commercial grade tire capable of working hard at the job-site and playing hard off-road.  This no-compromise tire offers the consumer features like:

  • Cooper Tire Armor-Tek3, three-ply carcass construction for added strength and off-road puncture resistance when compared to competitive two-ply products
  • Large surface area tread elements for positive grip and even wear
  • Stone ejector ribs to reduce tire damage due to stone drilling
  • Hybrid 4-5 rib design tread for low pattern noise
  • Dual-draft / non-parallel tread groove walls for further stone ejection performance
  • Enhanced buttress design side-wall lugs for additional off-road traction and reduced lug tearing
  • Outstanding cut-n-chip resistance
  • Enhanced off-road durability and treadwear

Note:  Cooper Tire did not provide competitive products for comparison of the Discoverer S/TMAXX. 

Mud Terrain Tire Tests

First up, the rock garden, modeled after the Rubicon Trail, right down to the rock material, rock sizing and placement.  The test vehicle would be a Jeep Cherokee equipped with a lift, lockers and of course, a set of Cooper Discoverer S/TMAXX tires.  How did the Discoverer S/TMAXX do?  In a word, great.  They conquered various obstacles with little slip and showed no signs of wear or tearing after repeated runs.

Cooper TiresNext, the CTVTC hill-climb.  This thirty degree incline sported three surfaces, standard concrete, polished concrete and rock-embedded concrete, each coated like a mini Niagara Falls with a steady flow of water.  Rather than mess with the standard concrete, I went straight for the polished concrete.  The test would begin from a full stop once all four tires were on the wet, 30° incline.  To my amazement, the Cooper Discoverer S/TMAXX pulled straight up the wet, polished concrete without a single slip.  I even stopped midway to give the throttle a little blip and still no slippage.  Next up, the rocky surface.  Like the prior test, the Cooper Discoverer S/TMAXX equipped Cherokee went up and over without any drama. 

Now that confidence was running high in these tires, we hopped in a modified Ford 150 for high-speed runs around the Cooper off-road course.  At speeds exceeding 100 MPH, the Cooper Discoverer S/TMAXX tires showed excellent handling and grip.  Perhaps most impressive was the braking performance of the tires on a mixed dirt/gravel surface.  The tires put me hard into my seat belts.  Impressive grip, indeed.

Last in the series of tests would be trail riding in Jeep Cherokees equipped with Cooper Discoverer S/TMAXX tires.  My goal was to stay in 2WD as much as possible to fully test the Cooper grip.  I was not disappointed.  These tires were unstoppable on hills, in ravines and through knee-deep mud bogs.


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The Verdict

The Cooper Discoverer A/T3 and Cooper Discoverer S/TMAXX tires performed well in all tests, with the Discoverer A/T3 even upstaging industry recognized leaders in wet handling comparisons.  The Cooper Discoverer A/T3 provided a sure-footed foundation on the road and off while the Cooper Discoverer S/TMAXX instilled a high-level of off-road confidence.

If you are in the market for high performance on and off-road tires for your truck or SUV, you should feel confident in the purchase of Cooper Discoverer A/T3 and Cooper Discoverer S/TMAXX tires.  Lastly, if you want the satisfaction of knowing that you can have all of this while supporting a US-based company producing tires right here in the USA, look no further than Cooper Tires. 


Cooper Tire & Rubber Company
701 Lima Avenue
Findlay, OH 45840-2315
Phone:  419.423.1321
Web: www.coopertire.com 

About Rick Webster

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