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Tire Test: We Take The BFGoodrich Mud-Terrain T/A KM3 on a 10,000-mile Torture Test

Posted in How To: Wheels Tires on July 5, 2018
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What better way to ring in the arrival of BFGoodrich’s new mud tire than to spin them across the country through every imaginable terrain? Yes, you read that correctly. In the span of 10,000 miles we found a blizzard, mud bogs, sand dunes, gravel roads, rain, dirt, rocks, and open highway. After our six-month torture test, not only did we confirm that the KM3s are indeed round and black, but they can also hold their own against the perils of on- and off-road use.

Taking a quick trip back in history, BFGoodrich debuted the world’s first radial light-truck performance tire in 1980—the Mud-Terrain T/A. Fast-forward to 2001 and the company gave Four Wheeler a look at the newest addition to the lineup, the Mud-Terrain T/A KM. For anyone curious about the tire’s moniker, “KM” stands for “Key benefit Mud traction,” and “T/A” indicates “Traction Advantage.” After serving for nearly a decade as the company’s mudder, the Mud-Terrain T/A KM2 has now been replaced by the KM3, and we were more than glad to trim the stock wheels on our ’17 Wrangler JK with a set.

In addition to the tires on our test Jeep, we met BFGoodrich in Moab, Utah, for some extra-special testing on the area’s signature slickrock ledges and sand. Between our Jeep and the company’s JK Unlimited, we logged some serious dirt miles among the red rocks.

The Road
Unless your rig is a trailer queen, there’s a good chance your most-frequented terrain will be pavement. Around town the largest difference between the Jeep’s stock rubbers and the KM3s were the visuals. The tire reminded us of James Bond—sharp looks and refinement on the road, but ready to fight to the death at a moment’s notice when the terrain turns sticky. Partially responsible for the good looks are the sidewalls. BFGoodrich fans will recognize the similarities between this tire and the company’s Baja T/A KR3, both featuring CoreGard Max technology, which is said to prevent sidewall splitting and puncturing. Also contributing to the tire’s eye-catching appearance is the Terrain-Attack tread design. The sharper edges and updated siping pattern made it hard to avoid staring at the new rubbers, even before we had them hub-deep in mud.

Diving headlight-first into the honeymoon phase with the new tires involved a quick 1,000-mile road trip from Los Angeles to Tucson, Arizona. Over the twenty-something hours on the interstate, we got an appreciation for the tire’s vocals. As a preface, the Jeep is not the world’s quietest vehicle, and even with the stock tires the road noise in the Wrangler is appreciable. That being said, with the stereo muted and ears attentively tuned, our tires were polite, only raising the volume into the “noticeable” category when the Jeep (albeit seldomly) went above 70 mph.

The three polyester plies in the sidewalls were happy to bend and fold themselves around rocks once we aired the tires below street pressure. Worried about sliding sideways off the rocks? The Terrain-Attack tread pattern makes sure you have biting edges contacting the ground at all angles, keeping the tires where you want them. Worried about sidewall tears? We were told the sidewalls are 27 percent stronger than those of the previous mud-terrain.

The Rocks
The jagged metamorphic rocks of Tucson were some of the first rocks we rolled over with the KM3s. Though rough around the edges, Tucson geology can take on a polished look much like that of a billiard ball. No sweat for these tires. The rubber compound appeared to be softer than that of previous mud-terrains and suction-cupped itself to even the slipperiest of boulders like the feet of geckos. BFGoodrich calls this the Krawl-TEK compound and claims the KM3 offers an 8 percent improvement in rock traction over the previous mud-terrain.

Though rock traction is commendable at street pressure, the real potential of these tires was unlocked when we aired down. The Linear Flex Zone was at work as the tires smeared themselves over ledges and stones alike, letting the sidewalls ooze and flow over the obstacles. It seems fair to mention this Jeep was equipped with neither a lift nor lockers—so sometimes completing the trail meant getting generous with the throttle, and spinning the tires. The burly sidewall construction and thick shoulder rubber let us spin with confidence. The tires took their share of gouges, scuffs, and scrapes, and oftentimes the sidewall was the only part of the tire grabbing onto the rocks—but not once did we hear the dreaded “whoosh” of a sidewall laceration.

The Gravel
With a job like ours, therapy comes in the form of cruising gravel roads. We are the types who will detour from the interstate with the sole purpose of inserting some crushed rock into the monotony of our travel—and the KM3s were in full support of our decisions. Sprinkled between the tread blocks are raised triangular knobs tasked with punting out stones that try and embed themselves between the lugs. Stone drilling occurs when gravel remains between the treads and can lead to annoying punctures. We experienced nothing of the sort and were all-around pleased with the tires on gravel roads. Even when we got a bit throttle-happy in the loose turns, the KM3s held and released their grip as expected for a mud-terrain tire, while still letting us have fun.

The Snow
For anyone who drives in snow, we had the privilege of turning down the temperature knob and burying the KM3s in some white stuff. Though these are not dedicated snow tires, we cruised straight past the chain-up stations during our time in the mountains. With temps hovering around 0 degrees F and the highway coated in the half-plowed snow and slush combo, we not only kept the Jeep on the road, but happily between the lines as the lugs bit through the mush and stayed in contact with pavement.

For not coming with a Three-Peak Mountain Snowflake rating, the KM3s shoveled their way through the snow and even kept us tracking straight on the snowy highways. We’ve seen tires harden and lose effectiveness in extreme cold, but with the mercury around 0 degrees F the tires still clung to the frostbitten trails.

Deep snow proved to be a challenge—not to the tires, only the Jeep. Eating through shin-deep powder to find mud and rocks below was easy, even to the cold rubber. The tread blocks tossed out the snow while the tires spun down to terra firma. Even in off-camber snowy tracks we had enough lateral grip to maintain our lines and avoid sliding off the shelf roads. Despite the Jeep being low to the ground and pushing snowplow-style through the deeper snow, we were impressed at how far we were able to dig through the forest roads before the winch cable was unspooled.

During the 10,000-mile test, this is the only time we got stuck—and that snow was bumper-deep, heavy, and wet.

The Sand
Whether it was cruising the beach or ripping across an inland dune, the KM3s did not let us down in the sand. When aired down to 18 psi, we had no trouble starting off or steering in the deep sand. Even more impressive was the sand performance at street pressure, since we weren’t always within reach of a place to air our tires back up. Though definitely not dedicated sand paddles, we were able to float across the sand in places where street tires have left us digging out the recovery gear.

Flotation is the concern in the sand, especially with mud-terrains. Even at street pressure, the KM3s pulled the weight of the Jeep through the dunes while keeping us from digging straight down in places where stock tires have left us buried.

The Mud
Testing a mud-terrain tire would not be complete without a real trip into the slime, and it is safe to say that the KM3s come alive in the mud. Deep within the rain-soaked, rutted-out backcountry of Ohio, we tried our darndest to get ourselves stuck. Locals say the mud here is like porridge mixed with cement, with enough suction to swallow tracked vehicles. Having been through this country before with all-terrain tires, it was fascinating how the BFGoodrich mud-terrains made mountains into molehills. Even when gunky ruts tried to direct the Jeep sideways instead of forward, the Terrain-Attack tread blocks were there to keep us on track. The real fun came when the trail slogged through a mud bog and promptly ascended a grade of buttery boulders and roots. With some wheelspin, the Mud-Phobic Bars between the lugs helped break the suction, void the treads of packing goo, and keep chewing hungrily up, over, and through the trails.

The KM3s are born for mud. The tread blocks chewed through the ruts and bogs of the Ohio backwoods, keeping us moving forward where all-terrain tires have left us mired down before. The Mud-Phobic Bars performed valiantly, covering the sides of the Jeep in slime, as they helped the tires clean themselves and maintain traction.

Thoughts After 10,000 Miles
We were not gentle with the BFGoodrich KM3s, and one of the biggest surprises was how the spare tire remained untouched—since we have a reputation for needing those more frequently than we’re proud to admit. The tires started with a tread depth of 18/32 and after 10,000 miles measured 16/32. Looking closely at the tread blocks, there were signs of scratches and nicks, which was expected for the way we frequently spun the tires to get up and over rocks (open differentials, remember?), but no damage we’d call “chunking.” Balancing was never a problem for this set of tires and the Jeep remained stable above 70 mph. The 285/70R17 rubbers weigh in at 67 pounds each compared to 36 pounds apiece of the stock Jeep tires, and even with the added weight we’d choose the KM3s every time. Expect to see these in sizes up to 39 inches in diameter for 15- to 22-inch wheels.

Open differentials on the Jeep required some careful line choice, but the tires gave us the grab and go we needed to get up and over this and many other hillclimbs.

Specifications (as tested)

Tire: BFGoodrich Mud-Terrain T/A KM3
Size: 285/70R17
Type: Radial mud-terrain
Load range: E
Max load (lb): 3,195@80 psi
Sidewall construction: 3-ply polyester
Tread construction: 3-ply polyester, 2-ply steel, 1-ply nylon
Approved rim width (in): 7.5-9
Tread depth (in): 18/32
Section width (in): 11.5
Overall diameter (in): 32.8
Maximum psi: 80
Weight (lb): 67.3

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