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Merrell Skyfire review: lightweight trail running shoes ideal for tough trails

Merrell Skyfire are fast and floaty mountain runners for time-orientated skyline scamperers

Merrell Skyfire
(Image: © Pat Kinsella)

Our Verdict

An excellent and supremely light and comfortable shoe for running very fast on rough, tough and technical trails, so long as the conditions underfoot are not too soft and skiddy.

For

  • Comfortable
  • Extremely light
  • Built for speed

Against

  • Lugs don’t cope with slippery mud well
  • Laces prone to coming undone

First impressions

In the right conditions, Merrell Skyfire trail running shoes are capable of absolutely blazing along tight, twisty singletrack trails at a redhot pace. They’re super light, with a mesh and TPU upper that weighs very little, and the dirt-facing face is armed with Merrell’s mountain-grade Quantum Grip 5mm lugs, intelligently positioned across the sole. The materials won’t keep water out if you encounter stream crossings, but they also shed moisture while you’re still on the move.

An internal bootie inside the mesh helps keep your feet securely in place, and the tongue is integrated with this sock to prevent the ingress of grit and small stones. The padding around the heel and below the ankle is generous, so they’re comfortable straight out of the box, and the EVA foam midsole cushions some of the impact of repeated footstrikes, and helps with stability. The design includes a rockplate to protect your feet from sharp sticks and stones.

Specifications

RRP: $100 (US) £100 (UK)
Weight (per shoe):  242g/8.5oz
Materials used: Mesh and TPU upper, EVA foam insole, Quantum Grip rubber outsole
Drop: 6mm
Colours: Lime forest / Skyfire orange / Black
Compatibility: Ideal for tackling mid-level mountain tracks and rubbly singletrack trails at speed

In the field

We ran over 200km in the Skyfires, in a whole range of conditions and across various terrain types, ranging from sun-baked corrugated mud on the Mendip Hills in late summer, to waterlogged trails on Exmoor and along technical sections of singletrack on the South West Coast Path. 

The 5mm Quantum Grip lugs are excellent on tight, technical, rocky trails – large enough and well positioned to inspire confidence without being so big and aggressive that they cause discomfort when you’re running on harder surfaces – but in our experience they struggled to perform in softer, muddier conditions, and we went for several unintended slides during gloopy descents. There’s no arguing with the comfort level of these shoes, though – they feel lovely from the very first wear. They’re luxuriously light and hug your feet beautifully, while allowing them to breath freely. 

They’re not waterproof, but neither do they claim to be – Merrell do actually do a Gore-tex version ($125 / £125), but the mesh outer on these shoes shed water very quickly, and we prefer this cheaper version for their nimbleness (the GTX versions will probably last longer, though, and both are very competitively priced). 

One little niggle we had was that the laces were prone to coming undone mid run – which is particularly annoying in a pair of shoes that otherwise encourages you to run fast. (And yes, we can tie our laces properly, honest – but many trail shoes these days offer a pocket to tuck laces away, or use an elasticized material in their laces that bites better and stays knotted, or employ a more innovative tightening method altogether, whereas the Skyfire come with very bog-standard shoe-laces).