Bigger Bite: Our Ford Raptor Levels Up With 37-inch Yokohama GEOLANDAR X-AT Tires

Few vehicles make a better test bed for an aggressive off-road tire than a Ford F-150 Raptor. Built from the factory to run hard in the dirt, soak up rough terrain and still behave like a civilized pickup on pavement, the Raptor demands a tire with a similarly broad range of abilities. With that in mind, we recently fitted our 2013 Ford F-150 Raptor with a fresh set of Yokohama GEOLANDAR X-AT G016 tires.

We didn’t take the conservative route, either. While Ford optioned the truck with 35-inch tires, our choice was a 37×12.50R17LT version of the Yokohama X-AT that adds a considerable amount of rubber beneath the first-generation Raptor. At roughly 37 inches tall, with a 12.50-inch width and plenty of sidewall wrapped around a 17-inch wheel, the combination looks right at home underneath a truck engineered from day one with off-road performance in mind.

Looks, however, are only part of the story. The GEOLANDAR X-AT occupies an increasingly important position in the truck-tire world, bridging the gap between a traditional all-terrain and a full-on mud-terrain. Yokohama refers to the X-AT as an “extreme all-terrain,” and after looking at its construction, tread design and specifications, it’s easy to understand why.

Somewhere Between an A/T and an M/T

Yokohama introduced the GEOLANDAR X-AT in 2019. The original lineup consisted of 27 sizes covering 15- through 22-inch wheels. Yokohama subsequently expanded the family significantly, eventually announcing more than 80 sizes as demand grew for aggressive all-terrain tires aimed at pickups, Jeeps and SUVs.

The X-AT’s mission has remained consistent from the beginning: provide considerably more off-road capability and protection than a mild all-terrain without forcing owners to accept all the road noise and compromises associated with a dedicated mud-terrain.

When the tire was introduced, Yokohama senior product planning manager Bob Abram summed it up by saying, “It offers ultimate off-road performance without sacrificing any on-road comfort.”

That’s an ambitious target, but it makes plenty of sense for a Raptor. Trucks like ours may spend their weekends hammering through dirt, rocks and desert terrain, but they still must cover plenty of highway miles between adventures.

A Closer Look At Our 37

For our truck we opted for part number 110116004, which is the 37×12.50R17LT 124Q version of the GEOLANDAR X-AT G016.

The tire’s 124 load index equates to a maximum rated load of 3,525 pounds per tire. Unlike many large modern LT tires, this particular X-AT carries a Load Range D, or 8-ply rating, rather than an E or F designation. Maximum inflation pressure is 50 psi.

That Load Range D construction is a great match for a performance-oriented off-road truck. Heavier load ranges have their place, particularly underneath diesel-powered heavy-duty pickups carrying substantial loads, but additional capacity usually comes with a stiffer and often heavier carcass. The D-rated 37-inch X-AT still offers far more load capacity than our Raptor needs from an individual tire while retaining a construction well suited to a trail-oriented application.

Yokohama specifies a 10-inch measuring rim for this size and approves it for wheels from 8.5 to 11 inches wide. Tread width is approximately 10 inches, while the tire begins life with a substantial 19/32 inch of tread depth. The tire’s overall diameter measures out at approximately 36.8 inches, the section width at roughly 13.1 inches and the tire weight at approximately 76.9 pounds.

Big Tire, Small Wheel

There’s another reason we like the 37×12.50R17 combination: sidewall.

A 37-inch tire mounted on a 17-inch wheel leaves a tremendous amount of rubber between the rim and the trail. That’s a real advantage once pavement ends. A tall sidewall gives the carcass room to flex when tire pressures are reduced. Instead of bouncing over an obstacle, the tire can better deform and conform around rocks, ledges and uneven terrain. Airing down can also lengthen the contact patch, improve flotation in soft terrain and help take some of the sharpness out of small impacts.

Compare that with a 37-inch tire mounted on a 20- or 22-inch wheel and the advantage becomes obvious. Large wheels may have their place, but for a truck that’s expected to work in the dirt, the combination of a 37 and a 17-inch wheel provides a lot of usable sidewall.

That sidewall is also one reason tire construction matters so much.

Geo-Shield Protection

Yokohama built the X-AT around its Geo-Sheild construction, which uses multiple sidewall plies, a high-turn-up carcass and a full nylon cap to improve durability and puncture resistance. Additional sidewall protection helps defend the tire against the rocks, debris and impacts that come with real trail use.

That becomes particularly valuable when a tire is aired down. Increased sidewall flex improves traction, but it also allows more of the sidewall to come into contact with the terrain. A sharp rock positioned in the wrong place can quickly ruin a day on the trail if the tire isn’t built to withstand that abuse.

The X-AT’s protective construction is therefore more than a marketing exercise. On a 37-inch tire with this much exposed sidewall, it addresses one of the areas most vulnerable during serious off-road use.

Tread That’s Built To Bite

The tread itself is every bit as purposeful as the carcass. Yokohama uses large, angular offset center blocks to provide strength while creating numerous gripping edges. Out toward the shoulders, the blocks vary in length, creating additional biting surfaces while helping the tread evacuate mud and stones.

Those large shoulder blocks are particularly useful once the trail gets loose. They’re designed to dig into dirt and gravel while providing lateral traction as the truck moves around underneath the driver. The open spaces between the blocks also give mud and debris somewhere to go instead of allowing the tread to immediately pack solid.

Sipes and narrow grooves incorporated into the tread blocks add additional edges for wet surfaces, snow and slick rock.

This is where the distinction between an ordinary A/T and an extreme all-terrain becomes obvious. The X-AT has the aggressive voids and shoulder treatment enthusiasts want for genuine trail work, but the tread hasn’t been opened up to the degree you’d see on a dedicated mud-terrain.

HD-2 Compound Takes The Abuse

Tread design only gets you so far if the rubber itself can’t survive hard off-road use.

Yokohama’s answer is its HD-2 Off-Road Compound, a triple-polymer blend developed to combine tread life with cut- and chip-resistance. Yokohama specifically points to sharp gravel, rocks and trail hazards as the type of abuse the compound is intended to withstand.

Anyone who has spent time on rough rocky trails knows how important that can be. Off-road tires don’t simply wear away evenly like a highway tire. Sharp surfaces and wheelspin can attack the leading edges of tread blocks, producing cuts, chips and eventually chunks of missing rubber.

The X-AT’s compound is designed to resist that type of damage without sacrificing the longevity expected from a tire that will also spend significant time on pavement.

That durability is backed by a 45,000-mile limited treadwear warranty on LT-metric GEOLANDAR X-AT sizes such as ours.

Making An Aggressive Tire Livable

One of the most difficult engineering problems with any aggressive off-road tire is noise.

Large tread blocks and deep voids can produce an unmistakable hum as they repeatedly contact the pavement and move air through the tread. Anyone who has spent hours on the highway with a loud mud-terrain knows how tiring that can become.

Yokohama addresses that problem with what it calls Five Pitch Block Variation. Instead of creating a tread pattern that repeats at exactly the same frequency around the tire, the block arrangement is varied to break up repetitive sound. Zigzag grooves further interrupt airflow through the tread in an effort to reduce pattern noise.

What we’ve noticed as we’ve logged miles on the tires is a fairly quiet ride while still retaining aggressive off-road capability. Coasting at 65mph there is a slight audible hum. However, it’s quickly drowned out by every other noise the truck makes once back on the throttle.

Two Looks In One Tire

The X-AT also has one feature that doesn’t affect traction at all but is still worth mentioning: a dual-sidewall design.

The two sides of the tire have different sidewall treatments, allowing the installer to choose which appearance faces outward. With a tire as large as a 37, the sidewall contributes considerably to the truck’s overall appearance, so having a choice is a nice touch.

A Few Things to Keep in Mind

As aggressive as the X-AT looks, buyers shouldn’t confuse tread appearance with every possible form of traction certification. This particular 37×12.50R17 is not Three-Peak Mountain Snowflake certified.

The tread includes plenty of edges that can provide mechanical grip in loose snow, but drivers who regularly encounter severe winter conditions should understand the distinction. If snow and ice performance are the primary buying criteria, a dedicated winter-oriented or severe-snow-rated all-terrain may be a better fit.

The Q speed rating is another reminder of what this tire is designed to do. A Q-rated tire carries a maximum rated speed of 99 mph. That’s entirely appropriate for a heavy, aggressive 37-inch off-road tire. This isn’t a tire intended for sustained high-speed pavement work; it’s intended to haul a truck through terrain that would make a street tire surrender.

Why the X-AT Makes Sense On Our Raptor

A Raptor creates an unusual tire requirement.

Its off-road capability justifies something considerably tougher and more aggressive than the average all-terrain, but the truck is still comfortable and capable enough to rack up serious highway mileage. A dedicated mud-terrain can deliver outstanding off-road performance, but for owners who aren’t spending every weekend searching for deep mud, the additional noise and road compromises aren’t always worthwhile. The GEOLANDAR X-AT lands squarely in that middle ground.

It’s aggressive without being one-dimensional and tough enough to complement a truck designed to spend its life transitioning from pavement to dirt and back again. And it’s that combination that makes the GEOLANDAR X-AT so appealing.