Merrell MTL Long Sky 2 Review: Voltron of the Trails? Voltrail?

What You Need To Know

• Weighs 10.5 oz. (297 g.) for a US M10.5 / 8.6 oz. (243 g.) for a US W8
• The (almost) perfect mix of Merrell’s designs
• Float Pro foam and Vibram rubber have us feelin’ fine
• Not quite as long as its name would suggest
• Available this summer for $130

TAYLOR: I’m usually late to the game on pop culture. Either that or I miss the game entirely. My wife and I just watched How I Met Your Mother for the first time. I may often be out of the loop, but I know what I like and am totally content with it.

For the most part, before I joined up with BITR, I also knew my preferences when it came to running shoes. After a few years and well over 100 pairs of trail shoes, I’ve broadened my perspective and whittled down what would make a perfect pair of dirt diggers, but here’s what I’ve realized: There’s no glass slipper. There are just too many variables in the trail world to say this one or that one reigns supreme, but a few stick out of the crowd.

Merrell is a dark horse that keeps saddling up. It surprised the crap out of us with the original MTL Long Sky, MTL Skyfire, and caught us again on the Moab Flight. The new MTL (Merrell Test Lab) Long Sky 2 is on the docket now. It’s tagged as a ready for anything mountain-runner, so it should be slim, nimble, and durable — or so we hope.

It’s similar to the first iteration with a few key changes. For starters, it’s lighter (10.5 oz for a US M10.5), more durable, and all-around more versatile. You’ll find features like the Float Pro midsole that we all loved in the Moab Flight, a Vibram Megagrip outsole with 5mm lugs, and an environmentally conscious breathable upper. Though they sound simple, these updates make me drool like a hungry bulldog.

MATT: Merrell is a brand that’s consistently flown under the radar yet always delivered top-performing trail shoes for the past few years. After putting a ton of miles on the Skyfire and Long Sky 1, it’s become our holy calling here at BITR to spread the good word of Merrell and everything it has to offer. Based on the previous offerings, I was already gearing up to heap praise on the MTL Long Sky 2. What initially caught my eye was that the midsole would be getting an overhaul, leveraging the Float Pro foam that was featured in the Moab Flight, another big winner from the brand in 2021.

The Good

TAYLOR: I’m gonna be straightforward here. There’s no question about the Long Sky 2 as a solid technical terrain trail shoe. It is, got it? Stop sleeping on Merrell, people.

What makes it so? Simplicity is part of it. In fact, the Merrell shoe that we collectively liked the least happens to be the most complex in design (Agility Peak 4), and we still thought it was a positive showing.

Overall, the MTL Long Sky 2 has the best ingredients from Merrell’s previous attempts. We’ve seen companies (Altra with the Mont Blanc) do something similar and fail to bring the pieces together in a practical way. Merrell straddles a fine line of thinking carefully about what this shoe needs to be without overcooking it.

The Long Sky 2 has a simple and breathable mesh upper similar to both the MTL Skyfire and Moab Flight. TPU overlays help retain the comfort traditionally found in mesh uppers while bolstering its durability. The few on the shoe also add structure to the toe and midfoot. It’s a great balance that allows for less stuff to inhibit natural movement, regulate temperature better, and keep the feet dry.

Thanks to the bootie-like tongue and light structuring of the upper (similar to the Agility Peak 4), this fit works for me. The closest comparisons to fit are the Merrell MTL Skyfire, Asics Fuji Lyte 2, Dynafit Ultra 100, and Saucony Mad River TR. There’s a little bit of room in the toe-box but not too much. Often, in a pair of technically oriented trail shoes, the toebox will be very slim for a nimble and secure fit (the Saucony Peregrine, VJ Spark, and many Inov-8s.).

A fine hug of the midfoot and a tight embrace around the Achilles keeps the foot locked in and comfortable at the same time. Nothing needs to be ratchet-strapped to get a fit that you’re 100% confident in. Once I figured out lacing for a tight heel-lock, the foot security was even better than that of the Skyfire — which is saying something. Over technical terrain, it even made me reminisce on miles in the Speedland SL:PDX. From breakneck speeds on technical to easy rolling terrain, this fit kept me locked in.

Underfoot is where the magic is happening. Float Pro is a light, durable, semi-responsive foam that debuted in the Moab Flight. The stack of 23.5mm to 19.5mm keeps runners low to the ground for control and some connectedness. At the same time, the durometer of the Floatpro foam is just enough to get a cushioned and protective sensation. It was similar protection to the Salomon S Lab Ultra and Adidas Terrex Speed Ultra.

Five millimeter Vibram Megagrip chevron lugs bring a lot to this package too. The compound is designed to be incredibly versatile. It takes on anything from dry and dusty to downright sloppy with almost zero issues. The only condition that I wasn’t entirely confident in was a couple of inches of fresh wet snow. Snow on top of rocks cannot be tamed.

Why not add a little more confidence to the bundle? Gaiter attachments are clutch for this one as the Long Sky 2 is a magnet to the off-trail and messy areas of wilderness.

The fancy bow on the Merrell MTL Long Sky 2 is that this shoe rocks in the performance category while being one of the more sustainable designs on the market. It’s a highly relevant topic in our world’s current state. Recycled fibers and plastics are mixed all throughout the shoe. It’s not a shoe entirely made of recycled materials, but this is a huge step in an industry that is wasteful beyond belief. Kudos.

MATT: The original Long Sky was a huge hit with the BITR trail team when it came out. I feel confident saying that despite Merrell making some significant changes, the Long Sky 2 is a move in the right direction, and it’s better than its predecessor.

As has been common across Merrell trail models, there’s a commitment to keeping things simple and having a purposeful design. This is something shared with Atreyu and part of why we’ve had high praise for both brands.

The mesh upper is super breathable, has the right balance of flex and fit, and is capped off by an integrated liner/tongue structure that really works well as an entire unit.

One of the big changes in the latest Long Sky is the midsole, where Merrell shifted to its Float Pro foam, a material that excels at sprinkling just enough cushion on top of a firm, secure ride that provides excellent ground feel. I first tested the Float Pro foam in the Merrell Moab Flight and really liked it then. Interestingly, with how the rest of that shoe was constructed, the foam had a more cushioned feel, but at the expense of the ground feel. Now combining that same midsole foam with the other components of the Long Sky 2, Merrell was able to create a different ride tailored for the technical terrain.

Finally, Merrell’s use of a Vibram outsole provides confidence and security across almost any terrain or conditions you throw at it. Considering the consistent performance of Vibram outsole technology, it amazes me that shoe companies are struggling with poor-performing outsoles. Stop overthinking it and go with the tried and true (not naming any names here, but there is one company that should JUST DO IT.)

The Bad

TAYLOR: This shoe has been a long time coming. I was so excited to have it before summer because, on paper, it’s a pretty ideal mountain slammer. Upon arrival, I ripped open the box to wear it around. Doom. Almost immediately, I could feel the heel slipping vertically. No flippin’ way can this be happening on a shoe like this. Thankfully, I was able to get a very nice lockdown just by swinging the laces through the bottom eyelets (near the collar) from the opposite direction as other eyelets entered. Don’t scare me like that, Merrell.

I did experience some subtle irritation from the stitching at the top of the tongue once I got the lacing figured out. The stretchy mesh folded over at the seam and exposed the stitching to my ankle, but I’m feeling it less and less as the shoe wears in. Something good to note is that I almost always wear crew-length socks. If you’re keen on no-shows, this irritation could be an annoyance, to say the least.

This last thing is more of a caveat than a negative. The name long sky might lead one to conclude that this is meant to be a LONG (ultra) distance shoe. To reiterate, this is a technical terrain shoe. Sure, you could go a long way in comfort, but there’s a lack of cushioning for those truly long events that span more than half a workday.

MATT: So this may be just a comparison thing, as many of the shoes I have been testing of late are geared towards max cushion and long days, but the Long Sky is not that type of shoe. The shoe is firmer and more secure than it is bouncy and cushioned, which is completely fine. Just know what the shoe is targeted for before you buy it. If 90% of your trail runs are on wide fire roads or rail trails, wearing the Long Sky 2 would be like lighting a candle with a flamethrower.

My only minor issues with the shoe weren’t deal-breakers and could be mitigated with sock choice or lacing style. As Taylor mentioned, I found I needed to utilize the very top eyelet to get my heel locked in, but it elevated where the laces rested, and they almost sat above the tongue. The sock liner/bootie could have been a bit longer in the tongue area to address this, but as an alternative, you can just wear crew-length socks.

Merrell MTL Long Sky 2 Conclusion

TAYLOR: Merrell MTL Long Sky 2, you did it. This is a shoe that I’ve been waiting for since the MTL Skyfire. It takes the nimbleness and secure fit of the Skyfire and adds more underfoot comfort and durability to the package. Are you an OG Long Sky fan? If so, I think you’ll be happier than a hummingbird chugging an unattended Kool-Aid pitcher. It has everything one would want in an update.

This could be your jam if you’re looking to run fast with confidence over technical terrain. I know it’s mine. This is the type of shoe that, when in its element, it is hard to find anything that you’d change. I’ll reach for the MTL Long Sky 2 when I’m looking to move through the mountain swiftly or for races with some gnarly terrain (with a 50k ceiling for most folks).

MATT: It’s officially time to stop overlooking Merrell. Honestly, this is long overdue since Merrell has consistently churned out top-performing models over the past three years that I’ve been reviewing with BITR.

The Long Sky 2 takes components from the OG Long Sky, the MTL Skyfire, and the Moab Flight models and meshes them into a Merrell Voltron (if you get that reference, time to join me for your daily glass of Metamucil). For anything from 5 miles to 50K, especially if the terrain is technical or conditions are sloppy, you would be well equipped with the Long Sky 2 underfoot.

You can pick up the Merrell MTL Long Sky 2 for $130 by using the shop link below.

Want to learn more about how our review process works? Check out this guide.