Merrell MTL Long Sky Review: Ultrarunner-Designed Trail Shoe

Merrell will release theMTL Long Sky trail-running shoe, designed with ultrarunner Anna Frost, in November. We got an early test on these trail runners and put them to the test in the Grand Tetons.

As we set off from Granite Canyon Trailhead, I knew I was testing my luck. Taking a shoe out of the box, putting it on your foot, and running 23 miles is not a great formula for anything but blisters. But hell, my racing season was over and peer pressure was being laid on thick. Why not give it a go?

Along with four others, I had come to Jackson to test a pair of soon-to-launch trail shoes by Merrell. Primarily known for its ubiquitous hiking boots, the Michigan-based brand quietly entered the trail-running market a handful of years ago and has started to make a name for itself. But, until this trip, I had yet to try a pair.

Merrell Long Sky

As an avid trail runner, I log a couple thousand miles every year and am always on the lookout for a better-fitting, lighter, grippier, faster shoe. The opportunity to spend 3 days running in one of my favorite places was too hard to turn down despite the cold and wet weather forecast.

Our first day was the longest, a near-marathon on the Valley Trail, with almost 4,000 feet of elevation gain. The trail was muddy and slick, making a good litmus test for the Long Sky.

In short: The MTL Long Sky is a middle-of-the-road trail-running shoe that should work well for many runners. It fits and average foot well. Its 8mm drop and luggy outsole make it a good choice for a large swath of trail runners.

Initial Feel: Snug, Comfortable Fit

Merrell Long Sky review

The MTL Long Sky fit well out of the box, and the first few miles were surprisingly comfortable. In fact, from the start of our run, I barely thought about the shoes — which is the biggest compliment a new pair of runners can get.

While this shoe is primarily designed to go longer distances such as ultras, it didn’t take more than a few hundred steps for me to break one in. As I test it more in the coming months, I’m curious to see how it holds up over a lot of miles. But for now, I’ll say it’s one of the more comfortable distance runners out there.

Traction: Good When Dry or Wet

Our route started with a few big climbs; one of the first things that struck me was the traction. Over the last couple weeks, I have worn the Long Sky in other conditions and terrain as well — rocks, roots, wet, and dry — and the shoes have yet to slip or slide.

The grip pattern and sticky rubber pair together to become one of the best trail shoes I’ve used, at least as far as traction goes. This was true for me when climbing or flying down technical descents.

Merrell’s secret is a totally new tread using a Vibram Megagrip rubber sole. It’s an aggressive pattern they spent 2 years testing and refining, and the result truly shows this effort. It’s designed for rugged mountain terrain and was designed in collaboration with one of the brand’s premier athletes, Anna Frost.

Support: Relatively Average

Merrell Long Sky test

The cushioning on the Long Sky is, relatively speaking, pretty average when compared with some of the other top-tier trail shoes on the market. While I didn’t have any issues or new pain on our long run in Jackson, I’m slightly concerned that I might over time. This shoe is designed to be a race-day speedster, meaning the design team at Merrell cut every ounce they could.

No shoe is perfect, and the Long Sky sacrifices some cushioning to make it keep the weight at just 10 ounces for our men’s tester size. As someone who has fought sustained hamstring issues, I value support very highly. It is one of the biggest factors for me when selecting a new shoe, especially something I’m going to train in for hundreds of miles.

Protection: Ready for Rocks

Testing the Merrell Long Sky

Despite running a lot, I’m still pretty mediocre. I kick a lot of rocks and sticks, trip on ruts, and slip on creek crossings all the time. So, a well-built, durable shoe is a priority.

I kicked quite a few rocks on our run in Jackson — a technical and rocky trail — and the shoes held up well. Sure, small sample size, but it’s still impressive to start. The upper is made from tear-resistant fabric and has an added protective material at the toe.

I was most impressed with how they felt when running through wet conditions. I stepped in the water several times, and they maintained their comfort level and warmth. The Long Sky has a breathable mesh lining and internal bootie for a well-sealed top that still allows water to drain. Even when wet, the shoe still performed well, with great traction and comfort.

Fit: Good for Most Feet

Merrell Long Sky trail running shoe

I have a very average foot, and the new Merrell foot box fits well. Others in the group with wider feet said the same thing — that the Long Sky could accommodate them as well. The new split-sole design allows the toe box and heel to articulate independently, which helps as you roll over rocks and other obstacles.

When I occasionally step on uneven ground, this feature helps the toe move without pulling on the heel. This gave me a great deal of confidence and control compared to other shoes with a continuous sole and rock plate.

MTL Merrell Long Sky Features & Specs

  • Mesh and TPU upper
  • Reflective details for increased visibility
  • Traditional lace closure
  • Molded TPU heel counter for added stability
  • Internal bootie for locked-in fit
  • Breathable mesh lining
  • Removable EVA foam insole with medial post for light pronation control
  • Vibram Megagrip
  • Stack height (heel/toe): 24.5 mm/16.5 mm
  • Weight (one shoe): 10 oz. (280 g) men’s / 8 oz. (230 g) women’s
  • Drop: 8 mm
  • Lug: 5 mm
  • MSRP: $130