Sunday, March 15, 2020

Merrell MTL Long Sky Review: A Surprise Super Lively Midsole, Great Traction, and Reasonable Weight

Article by Sam Winebaum

Merrell MTL Long Sky ($130)


Approx Weight: 9.65 oz / 274 g US M9

Stack Height: 27.5mm heel / 19.5mm forefoot, 8mm drop

Outsole: Vibram MegaGrip, 5mm lugs

Available now. $130

I have run the Long Sky, on snow, mud, and more recently on dry single track trails.

The MTL Long Sky is an agile, well cushioned, flexible yet stable trail runner with a 5mm lug Vibram MegaGrip outsole.  At just under 10 oz / 274g it is a lot of shoe for its weight, The cushion is on the softer side providing welcome rebound while the outsole is aggressive for softer ground yet also is not in the way on hard surfaces including road. A really fine all terrain ride here.  

It sits squarely between shoes such as Salomon Sense Pro/4 or Skechers Speed TRL which are lighter and less cushioned and heavier duty and heavier shoes such as the Caldera 4, Peregrine 10, and Sense Ride 3  fitting in as an all around varied terrain option. It reminds a lot of the Hoka Torrent. We have also tested and reviewed the lighter Sky Fire which shares the same midsole although I personally did not.


  • Wonderful softer ride with plenty of rebound yet which for the most part is stable and protective. 
  • All terrain versatility, even road is fun yet it can also tackle snow and mud and everything in between
  • Great forefoot trail feel and agility, even if protection is a bit thin there
  • Well decoupled midsole/outsole and flexibility makes them smooth flowing at all paces
  • Generous fitting  easy to dial in upper that is secure and supportive


  • Low volume feet, especially at mid foot, may struggle with support on more highly technical terrain. 
  • No rock plate. The combination of softer midsole and the outsole design on the medial front side is a bit thin and lacking in protection.

First Impressions and Fit

Boldly (and reflectively) branded with a bright orange upper with a nicely offsetting greens and blues at the heel with minimal outer overlays (but inner ones are present and carefully placed) the Long Sky sure makes a statement.

The fit is generous and secure, especially if you have a broader midfoot as the combination of inner not particularly stretchy bootie, which is attached fairly far down and relatively high volume outer not particularly pliable and rugged open mesh make the midfoot wrap on lower volume feet a bit trickier. 

I have a medium to lower volume foot and wished for a bit more secure mid foot wrap for use on more technical rockier trails. On more moderate trails even somewhat technical ones the support was fine. 

The TPU heel counter is solid and well tied into the lace up by stout TPU overlays with the rear hold impeccable, no surprise given Merrell long heritage in hiking, 

The toe box has plenty of room for up to a broader forefoot. I was true to size but might consider a half size down to potentially get a better mid foot hold.


The outer upper is a very open and at the same time rugged thicker mesh. As it is not particularly pliable it can appear to fold awkward over the toe box but this has not been an issue. It is very breathable in moderate temperatures.

It has several inner and quite stout underlays on the medial side for support and I assume to provide a sort of internal protective rand while on the lateral side the overlays are external. 

The toe bumper is by no means overly firm but has proved protective and I expect will also prove durable. It is a pliable and quite thick material.

The inner bootie also is the tongue and is all of a single material, a three layer only  slightly stretchy sandwich of outer open mesh, inner white padding with holes, and a soft inner layer. It is attached far down towards the midsole. 

Overall the bootie system is comfortable and effective, adapting to different foot volumes but I wish the outer mesh was more pliable or slightly lower volume to better wrap the mid foot, lace up to rear being impeccable in comfort, stability, and support 

The webbing lace loops and semi flat laces are very easy to dial in. The prominent Merrell branding is all reflective, a nice touch.


The midsole is called out as EVA with a medial post for light pronation control. It sure does not feel like the usual EVA to me. On the soft side, very stable, and with some unusual for a trail shoe pleasant and noticed rebound it has plenty of cushion. The cushion is amplified by a relatively soft Vibram MegaGrip outsole  As far as the medial post it is totally  un noticed while the shoe is plenty supportive underfoot.

There is no rock plate here. Generally the rock protection is more than adequate for up to the most technical terrain where it may be a bit thin and with no rock plate the shoe is admirably flexible for smooth fast climbing. This said the medial forefoot about where the laces end tends to bottom out on toe off at the edges of the sole with the terrain maybe a bit to present in feel..(see purple mark below)

I wonder if a change to the outsole lug pattern in that area or a slightly firmer foam might help.


The outsole is Vibram MegaGrip with a multi directional 5mm lug height pattern. This is one excellent outsole. The grip on hard snow was among the best of any 2020 shoe, mud grip and mud clearance was also excellent. The softer rubber here also made the outsole an asset on road and hard pack surfaces by adding to the cushion and rebound story of the shoe increasing its versatility to truly all terrain. The outsole is well decoupled with a gap between front and back for what I found smooth any pace, up and down with up front plenty of flexibility for agile toe offs and great ground feel. All this great stuff may a touch too much of a great thing as I might see more outsole lug coverage on the medial forefoot to resist the compression of the midsole there a touch more.


I was very surprised by the ride here, and on all surfaces from snow, to mud, to hard pack single track and even road. On the softer side for a trail shoe with lots of rebound but generally very stable, every run was a big smile. There is enough cushion here for big distances and it is light enough for short and fast. This said the forefoot may be a bit to soft for more technical terrain, not in the sense that the shoe lacks agility and flexibility but it feels like that medial forefoot side is compressing a bit to far leading to a few rock bites there and potentially during long runs on more technical terrain some medial forefoot fatigue.


Said it Ride and will say it again in Conclusions, the Long Sky was a big and pleasant surprise. it is versatile for just about any trail (or even road) terrain, and for runs up to decently long distances on smoother terrain, and has a lively, agile softer ride with rebound which is the shoe's highlight.

But for a bit more under foot protection up front on the medial side of the sole, from firmer foam or more outsole and potentially a bit less dense more foot wrapping outer upper to go with the bootie for lower volume feet, it would be a top top contender as my shoe of the year and may yet still be!

At approximately 9.65 oz / 274 g  in a US M9 with a stack height: 27.5mm heel / 19.5mm forefoot and its stout Vibram MegaGrip outsole Long Sky packs a lot of substance at a relatively low weight. For runs of 6 to up to 10 miles on mostly smoother Park City single tracks on both hard dirt and snow/mud often all mixed in it has been a grea full on Winter into now Summer companion.

Sam’s Score: 9.1 /10

Ride: 9.5 (30%) Fit: 8.5 (30%) Value: 9 (10%) Style: 9 (5%) Traction:10  (15%) Rock Protection: 8 (10%)

But for the mid foot fit and rock protection/ forefoot medial side softness the shoe would score higher yet.


Hoka Torrent 1 (RTR Review)

Somewhat lighter but still above 9 oz at 9.2 oz vs. 9.65 oz for the Merrell, the Torrent with a 5mm drop vs 8mm for the Long Sky has less heel stack and about the same forefoot stack. The Long Sky’s cushion is slightly softer and has more rebound while the Torrent’s forefoot is more protective and more stable as it has firmer foam up front than at the rear and firmer than the Long Sky’s, neither having a rock plate. I prefer the ride of the Long Sky and would call the upper fit a toss up with the Long Sky having a more accommodating toe box and more secure heel hold while the Torrent has a more secure midfoot. True to size in both.

Brooks Caldera 4 (RTR Review)

A very tight contest between these two, The Brooks weighs a bit less than half an ounce more but has a broader on the ground platform, more front protection and stability and a more secure upper. It wins on all those counts but the Merrell midsole is more lively and fun to run. Polish the forefoot protection and slight upper issues and the Merrell would be a clear winner but for now the Caldera leans at the tape for the win. Both true to size.

adidas Terrex Two BOA (RTR Review)

Very similar rides here, on the softer side, with the Terrex seeming to provide more softness from its outsole than the firmer Lightstrike midsole while the Merrell provides rebound and softness primarily from its midsole. The Terex is almost two ounces heavier and a bit more stable up front. The Long Sky is more agile and quick in feel while the Terrex upper with its similar heavy duty materials is more secure due to the BOA System. The weight difference tips the scales towards the Long Sky unless you plan to use the Terrex for ultra length runs over moderate terrain where it would be a better choice due to its upper support and somewhat greater forefoot protection.

Salomon Sense Pro/4 (RTR Review)

Somewhat lighter at 9.35 oz / 265 g but not that much lighter really, the Pro has a superior and really flawless upper for a medium to narrow foot. It’s ride is denser and given its ProFeel rock plate and Optivibe midsole more protective and also somewhat more stable up front.  The Long Sky has softer more lively cushion and is if not quite the speed rocket the Pro is, but easier on the legs and a better choice for training and longer runs on smooth terrain. True to size as with Long Sky if a more performance race type fit.

Salomon Sense Ride 3 (RTR Review)

A full ounce heavier the Ride 3 shines in its forefoot protection and cushion. It’s upper and rear support is flawless but maybe a touch overdone adding to its weight which tops the scales at 10.6 oz so a full once heavier So much dense cushion and protection for me that while it will get me further than the Long Sky, the overall ride is more dull and lifeless in comparison. True to size in both.

Saucony Peregrine 10 (RTR Review)

Considerably firmer, with less rebound and an ounce heavier, the Peregrine leans more technical terrain than the Long Sky. Its forefoot is protected (and stabilized better than the Merrell’s)  with a woven rock plate and is far stiffer with less distinct flex than the more agile for climbing Long Sky. It leans shorter distances on technical terrain for me (yet a a big weight penalty) while the Long Sky leans medium distances on smoother terrain

Nike Terra Kiger 5 (RTR Review)

Weighing slightly less than the Long Sky, the Kiger has more forefoot protection and stability, a more secure upper, but only adequate traction in comparison to the Long Sky. The React foam in the Kiger gets close to the Merrell midsole but is more dense in feel with less rebound.. Kiger is a faster, more agile and protective shoe but has not quite as pleasing a ride.

Watch the Video Review from the Trails in Park City

Tester Profile

Sam is the Editor and Founder of Road Trail Run. He is 63 with a 2018 3:40 Boston qualifier. Sam has been running for over 45 years and has a 2:28 marathon PR. These days he runs halves in the just sub 1:40 range training 30-40 miles per week mostly at moderate paces on the roads and trails of New Hampshire and Utah. He is 5'10" tall and weighs about 165 lbs.

Read reviewers' full run bios here
The product reviewed was provided at no cost. The opinions herein are the authors'.
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Marcel said...

looking forward to your full review! my impression so far (just walking around in the appartment, no running): a little wider forefoot than the Skyfire even though it is more pointed. negative: slight heel-slippage and even more important very noticable "cringling" of the material of the shoe below the ankle on the inside (hard to describe, escpecially in English, but i can even slide a finger down between the shoe and the ankle). probably a marathon-lacing would fix the problem but for marathon lacing the tongue - for whatever reason - is just too short:-( beside of this, a very comfy shoe. nonetheless, the Skyfire at least for me personally has a much better fit, especially below the ankle - it almost fits like a sock. the performance-fit of the skyfire is perfect in my opinion even though this makes the toebox a little to narrow for my forefoot but this problem exists with almost every standard-with shoe (current exceptions: Triumph 17, Novablast Tokyo Edition, Wave Shadow 3, Fujitrabuco Lite).

Scott said...

I've been loving my Long Skys. I took a chance on mail ordering these, relying on your review. My biggest concern was the 8mm drop but this hasn't been a noticeable problem so far.
I've been running on icy, hard-packed snow and some slush and find these a super-grippy and livelier ride than my OG Torrents. I've done 35+ km runs in them and still feel fresh.
In addition to training runs I'll be using these in muddier ultras or in the later stages of ultras when the higher drop and medial support might help me hold my form together.

Sam Winebaum said...

Hi Scott, ‘
Thanks for your feedback and comments. Glad they are working out well for you. Merrell while super reputable for trail hiking should be much more well known for running as their shoes are really fine.
Sam, Editor