Merrell MTL Skyfire

Merrell MTL Skyfire Review Analysis (2021)

Last update: May 2022

The Merrell MTL Skyfire is a lightweight trail running shoe to go fast downhill on the most challenging terrains.

The Consensus

9.2Overall score
A very good versatile and lightweight trail running shoe for tackling the most mountainous terrains!
Crafted specifically for taking on tough mountain trails, the Merrell MTL Skyfire is the perfect shoe for higher elevations and shorter running stints on uphill terrains. Its lightweight design (9 oz./242 g) coupled with its great traction and breathable fabric makes the MTL Skyfire an extremely prudent choice for off-trail runners.

Its stack dimensions are 23.5mm/17.5mm, with a drop of 6mm and lugs of 5 mm, to provide the best possible running conditions on rocky slopes. Runners who have tried the MTL Skyfire remarked that the sneaker was bouncy, comfortable, and provided a smooth running experience. However, according to recent studies, there is some discrepancy regarding adequate cushioning, which tends to be a stronger preference for female runners than male runners.

Runners have also stated that the MTL Skyfire is highly breathable but that this design comes with the pitfall of absorbing a significant amount of moisture straight through to the foot on wet trails or in rainy weather. MTL Skyfire users have also commented on the narrowness of the sneaker design, which is likely intentional to provide a snug fit for added security on rocky trails. This may make the shoe a great option for narrow to medium feet runners but may prove too tight for runners with wider feet. For best results, runners who tried the MTL Skyfire recommend tying the laces as tightly as possible for added heel and ankle protection. However, this may be unsustainable and prove to be too uncomfortable for longer runs.

Note that while the Merrell MTL Skyfire is ideal for shorter running sessions, cross-country runners will likely do better with the sneaker’s companion, the Long Sky. Runners were also a big fan of the Merrell MTL Skyfire’s reasonable price of only $100, which is relatively budget-friendly compared with other sneaker brands of the same high caliber.

Overall, the Merrell MTL Skyfire is a very good running shoe for off-trail, short-distance runners looking for a snug fit, lightweight design, above-average traction, and a great overall value! Longer-distance runners, or those who prefer a bit of extra cushioning, will do well to consider the brand’s Long Sky option as an alternative.
Value for money
  • Precise and safe foot lockdown
  • Comfortable and springy cushioning
  • Impeccable grip
  • Lightweight
  • Narrow shoes, especially in the forefoot area
  • Laces are not very practical and not so easy to adjust to find the right level of tightening



  • First of all, we find Quantum Grip on the outsole of the Merrell MTL Skyfire. This is a durable rubber designed specifically by the brand for the mountain. It allows the athlete to tackle the most difficult trails with confidence thanks to the shoe’s impeccable traction.
Merrell MTL Skyfire rubber outsole lugs


  • The midsole is equipped with EVA foam. Ethylene-vinyl acetate is a material known for its lightness and natural cushioning which is used in many sports shoes. It protects the foot from stones and the roughness of natural terrains. This platform promises a springy and fluid ride.
  • In addition, there is a rock plate that protects the foot from potentially dangerous rocks on trail terrain. This also improves the durability of the shoe.
  • Finally, the EVA foam sockliner conforms to the shape of the foot and completes the cushioning.


  • The upper of the Merrell MTL Skyfire features an engineered mesh with TPU overlays. This configuration is designed to effectively lockdown the foot during training for optimal comfort. Perforations throughout the mesh ensure good ventilation to prevent your foot from overheating during exercise when you’re going faster.
  • The inner mesh lining feels soft to the skin and helps the foot breathe in the shoe.
  • There is also an internal bootie that allows the foot to be wrapped comfortably and flexibly. In addition to preventing chafing irritations, it also provides a better fitting foot lockdown.
  • In addition, the external molded TPU heel counter comfortably locks-in the heel for a more comfortable and effective foot lockdown during running.
  • Finally, the reflective details allow the runner to be seen even at night for more safety.


Technical Specs

Pronation typeNeutral
Drop6 mm
Heel stack height24 mm
Forefoot stack height18 mm
FeaturesAvailable in GTX, Rock plate, Vegan
Weight (men)263 g/9.3 oz
Release year2020


OutsoleQuantum Grip
MidsoleEVA foam, rock plate, EVA foam sockliner
UpperEngineered mesh with TPU overlays, inner mesh lining, internal bootie, external molded TPU heel counter, reflective details

Reference: Merrell

Frequently Asked Questions (FAQs)

How does the Merrell MTL Skyfire fit?

This trail shoe follows a standard sizing system. Trailers who have tried it on confirm that it runs true to size. So you can choose your usual size for trail shoes. However, if this is your first pair of Merrells, a visit to the store can be wise to be sure to choose the best size.

Is this trail shoe suitable for heavy athletes (85 kg/187 lbs or more)?

To date, only one study has investigated the relationship between weight, sole thickness, and risk of injury. According to the conclusions of this study, minimalist shoes can increase the risk of injury for runners weighing more than 71 kg/157 lbs. Apart from this, there are no recommendations for other categories of running shoes. The MTL Skyfire has a stack height of 24 mm under the heel and should, therefore, be suitable for everyone.

Can you run an ultra-trail with this model?

This Merrell trail shoe is mainly recommended for short to medium distances at high speeds. However, it remains suitable for longer distances and at a slow or moderate pace. For ultra-trail, there is no special indication. If you find this shoe comfortable during your long runs, there should be no problem.

Is this shoe waterproof?

This model is available in two versions: Gore-Tex and standard. Thanks to its water-repellent nature, the standard version is designed to fend off small water infiltrations and dry quickly. Therefore, your foot should stay dry if you are running in light rain and passing through puddles. If the rain is heavier, your foot may get wet after a while. The Gore-Tex version offers better protection and keeps your feet dry even in heavy rain or when crossing shallow streams. However, we should note that the Gore-Tex version is a little more expensive and heavier. It’s up to you to see which one suits your objectives. The standard configuration has the advantage of offering sufficient ventilation of the foot during the effort and being lighter and more flexible.

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