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Trail Running Shoes • April 10, 2024

Inov-8 Trailfly Speed Review: Lean, Mean Technical Trail Machine

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What You Need To Know


9.5 oz. (270 g) – Average weight across all sizes

Stack Height / Drop

22 mm in hee, 18 mm in forefoot (4 mm drop)

Best For

Short, fast efforts on technical trails

Key Features

Graphene Grip outsole, Meta Shank rock plate, PowerFlo Pro midsole

On The Run
Aggressive Graphene Grip lugs Just enough protection to go fast Maybe not enough stack for long efforts
Price / Availability

Available now for $160

Introduction to the Inov-8 Trailfly Speed

SAM: There’s a new Inov-8 ’round these parts. UK’s resident bulletproof shoe maker has fully rebuilt its lineup of lasts and materials, and it has several new models on tap to show them off. So far, the brand’s 2024 launches have been focused on terrain and purpose — covering hard ground vs soft and distance vs speed. Each launch is also offered — or at least will be offered — in both precision and wide fits, opening up the flexibility for feet of all shapes and sizes. So far, we’ve put our feet in the revamped Mudtalon Speed and Trailfly, and now I’m here to dig into the Trailfly Speed.

The Trailfly Speed is the hard ground tempo and race day shoe in Inov-8’s revamped lineup. Instead of the “soft ground” directed upper and 8 mm Sticky Grip lugs on the Mudtalon and Mudtalon Speed, the Trailfly Speed has the shorter 4 mm Graphene Grip lugs and outsole configuration found on the Trailfly, a new Powerflow Pro midsole, a Meta-Shank rock plate, a 6 mm thick water-resistant beaded TPU Boomerang insole, and a single-piece air mesh upper. The total stack height is 22 mm in the heel and 18 mm in the forefoot for a 4 mm drop. If you read all that closely, you might have noticed that the lug height and insole take up over half of that total stack height underfoot, leaving barely the width of a shirt button in foam depth in the heel and almost half that in the forefoot.

I love a chunky max cushion cruiser as much as the next guy, but it’s always fun to tear up some singletrack in a slim, aggressive ripper of a shoe. The Inov-8 Trailfly Speed is made to do just that, and when it showed up, I was excited to get it out on the trails, even though I was a little worried about having so little under my feet.

What we like about the Inov-8 Trailfly Speed

SAM: As of this review, the Inov-8 Trailfly Speed is only available in the new wide last, although a precision fit is coming soon. I mentioned the fit of Topo Athletic shoes above, and while those may be the most similar shoes to this new Inov-8 direction, they’re far from the same. The Trailfly Speed fit true to size for me, with a slim midfoot and heel and plenty of room in the toe box. Seriously, there’s so much room. My toes love extra room, and there was more in the Trailfly Speed toebox than I usually find in Topo shoes or in Altra’s Standard Fit models.

The lockdown in the midfoot makes this shoe feel secure, aggressive, and capable on all manner of trails. Inov-8 calls the strategically cut transparent overlays on the air mesh the “Met-Cradle,” and they add plenty of support and protection without compromising the breathability of the upper.

The PowerFlow Pro midsole combined with the Meta-Shank rock plate feels like far more cushion than the 22 mm in the heel and 18 mm in the forefoot that actually exists. Now, some of the heavy lifting is certainly done by the 6 mm TPU Boomerang insole. Whatever the case, I never felt like I didn’t have enough underfoot, and there was even a little energy return. There’s no rocker and not enough midsole to feel properly “lively.” but the Trailfly Speed feels responsive and protective, and that’s exactly what it’s made to do.

Speaking of the Boomerang insole, the Trailfly Speed is the second shoe I’ve tested this year to come with a beaded TPU insole meant for comfort and to avoid waterlogging (the other being the Topo Athletic Pursuit 2). These insoles add comfort and responsiveness to the shoe and keep the squish away after water crossings. The one in the Trailfly Speed is even perforated to speed up drainage and drying. Count me as a fan.

Underneath the shoe, the Graphene Grip outsole adds even more confidence. This rubber has always been one of Inov8’s best assets, and it’s insanely durable and plenty grippy. Between the lockdown and the outsole, this is a surefooted shoe.

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What we don’t like about the Inov-8 Trailfly Speed

SAM: My test pair of the Trailfly Speed came in the blue/yellow colorway, and it’s just not my thing. It looks a little like someone skinned a dinosaur from a children’s TV show and made its hide into shoes. The red/black colorway Inov-8 has out is slightly better, but it’s still a little like a Diablo III character was going through an emo phase.

Other than my overly dramatic description of the styling, the biggest issue with the Inov-8 Trailfly Speed is just that the fit takes some adjustment and it might not be for everyone. The sleek heel takes a number of tries to get tightened correctly, and there’s no fully locked-in feeling from the heel cup. The toebox is wide enough that I might even call it too wide — I really had to cinch down the laces to keep the ball of my foot from moving around. None of this is specifically bad. In fact, I’m sure it’s great for certain feet, but I just never felt truly at home on my feet.

Finally, this is not a long-distance shoe. It feels protective, but even at the six to seven-mile mark, my feet would start to feel the pounding of the ground. I probably wouldn’t want to take this much over half marathon distance.

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Final thoughts on the Inov-8 Trailfly Speed

SAM: The Inov-8 Trailfly Speed is a nimble, aggressive, and very tough shoe for short, technical trails. I’m sure it will find its fans among the Inov-8 die-hards and newcomers alike because of the wider spectrum of feet it will fit. It’s a great shoe for trail runners who want something tough and fast and have specific fit requirements. Fans of the Topo Athletic Terraventure 4 and the Hoka Zinal 2 could find something to love here. I’m personally excited to see what Inov-8 does with their historic build quality and some of these new lasts.

You can pick up the Inov-8 Trailfly Speed for $160 from Inov-8 using the buttons below.

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Sam Edgin
Mid-Atlantic Trail Reviewer
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Sam lives in Baltimore with his wife and two kids and spends his days fixing espresso machines for Ceremony Coffee Roasters. He runs with the Faster Bastards when he can, races ultras, and has been working on completing the AT section by section. He thinks the best days are made of long miles on nasty trails, but that a good surf session, a really stunning book, or a day of board games are pretty all right too.

All-time favorite shoes: Saucony Xodus Ultra, Topo Athletic Ultraventure 3, Altra Lone Peak

More from Sam
Shoe Size


Fav. Distance


  • 6:15

  • 1:40:39

    Half Marathon
  • 21:30

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