The Inov8 TrailFly Zero V2. All photos: iRunFar/Eszter Horanyi
The day after Christmas when I slipped on the Inov8 TrailFly Zero V2 ($175) shoes for their first out-of-the-box trail adventure — for iRunFar reviewer Annie Behrend’s 15-mile birthday run — I knew instantly that Inov8 was serious about research, design, and executable improvements. With this new version of the TrailFly Zero, Inov8 made a sensible running shoe tangibly better. All the minor details that were a little off with the original are now a non-issue, a thing of the past. The fit and feel are both perceptibly dialed. On this first run, I ran the TrailFly Zero V2 in mud, rain, and snow, as well as on soft singletrack and dirt roads. They nailed it. Of course, they yearned for more rocks and hardpack, but they embraced the variety.
The TrailFly line offers something unique and satisfying for nearly every type of runner. There is the TrailFly Zero line, the Inov8 TrailFly Speed (review), the Inov8 TrailFly Max (review), and the Inov8 TrailFly (review) for daily training. Each of the models in V2 come in a standard or wide fit (the original Speed wasn’t offered in wide), showing that Inov8 is reading the needs of the greater trail running community. Although you can’t satisfy everyone, the company’s mission of natural foot function and ground connection keeps it real and steady in an ever-changing and ever-growing market.
I ran in the original version of the TrailFly Zero for months — resulting in the back-to-back testing of the two versions of the TrailFly Zero series. The original TrailFly Zero’s rhythm is being a steady trainer for hardpack trail running. A definite throughline from the original to the upgraded V2 is a reiteration of its reliability and steady performance on harder-packed and rocked surfaces, while not tentative on more technical and softer terrain. It is a shoe you don’t have to worry about because you know it can handle the weekly and quotidian runs — all year. Comparatively, the TrailFly Zero — both versions — ride similarly to the TrailFly Speed and the Topo Pursuit (review) with their footbed, style, and anatomical foot shape.
As the name suggests, the TrailFly Zero V2 is a zero-drop trail shoe. It rides with a 22-millimeter stack height heel to toe, with a slight rocker at each end. It has a claimed weight of 10.0 ounces (285 grams) for a U.S. men’s 9 — not light, not heavy. A zero-drop stack may be a hard sell for some individuals who aren’t biomechanically adapted, but for those runners with lower-limb endurance and an appreciation for down-trending minimalism, it’s a catch and keeper. However, I generally recommend a zero-drop trail running shoe for those who are ready, strong, and smart about their training. When it comes to zero-drop shoes, the TrailFly Zero V2 is a good place to start. The midsole and outsole provide suitable comfort without forgoing the ground connection and natural ride. The toebox honors wide toe splay and natural foot movement, but now with a more attuned overall fit and locked-in experience.
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Inov8 TrailFly Zero V2 Upper
A lateral view of the Inov8 TrailFly Zero V2.
The Inov8 TrailFly Zero V2 experienced necessary and notable upgrades. The redesign elements were primarily focused on the construction of the upper — how the runner experiences the outer shell and how the upper interacts with the environment. These changes made a considerable difference not only for the increased reliability of the shoe, but also for the shoe’s performance.
The TrailFly Zero V2 presents itself as a no-nonsense trail runner. Despite its possible lack in immediate aesthetic appeal, unlike the stealth TrailFly Speed with its blur of color, the upper undoubtedly performs its jobs — protection and lockdown. It is an unassuming workhorse. And while the upper’s all gray color was chosen purposefully, it fondly grew on me, and it goes well with everything. The TrailFly Zero V2 boasts not only beefier toe bumper protection but also thicker overlays on both the medial and lateral aspects of the shoe. These changes are profound for its overall durability, and for how it fits and performs during the gait cycle.
The Met-Cradle TPU overlays neatly tie into the lacing system for enhanced midfoot to heel lockdown — a much-needed upgrade. The original version suffered from loose heels and a voluminous midfoot, often giving way to unwanted space and movement. The overlays are doubly layered in some spots for extra abrasion resistance and upper toughness. In the latest version, designers carved out holes in the toe bumper for better drainage. Since this shoe runs all year round in every type of weather, these extra holes also function as ventilators in tandem with water release. It may read like the newer upper is a fortress, but it is just integrated protection.
The upper fabric is a multi-layer mesh that is smooth on the inside and guarded on the exterior, and is still breathable during hot summer months. It fully wraps around the forefoot, creating an integrated upper support system and an incorporated substrate for the overlay system.
Tongues and laces are always an afterthought — so it seems. As with most Inov8 shoes, I am not a fan of their basic, flat, slippery-feeling laces. The tongue on the original version was almost a dealbreaker. It was hard to keep it in place throughout a run. It would duck, sneak, and slide, and since the sizing wasn’t quite right the first time around, the extraneous and loose tongue was amplified. Inov8 is normalizing sizing across all their models, but I also understand there is a difference in sizing across nations and across the pond. The TrailFly Zero V2 fits wildly better, and it comes with a slimmer, smaller, and more stable tongue.
Inov8 TrailFly Zero V2 Midsole
A medial view of the Inov8 TrailFly Zero V2.
The Inov8 TrailFly Zero V2 has a FlySpeed Pro midsole, which is a supercritical nitrogen-infused EVA foam built for enduring support. The pulse of a running shoe resides in the design and construction of its midsole. That is not to say that the totality of the shoe doesn’t matter. It certainly does. However, the midsole is central because it is the immediate surface interfacing with our foundation — our feet and core. If it weren’t for the original TrailFly Zero’s FlySpeed Pro midsole, I probably wouldn’t have continued running in them.
I found the midsole of the TrailFly Zero V2 to be nimble, fun, and a firm comfort. The Boomerang footbed furthers this experience. As a side note, I first encountered a Boomerang insole in the Topo Traverse (review) and the Topo Pursuit. I quickly became fond of TPU compression beads underfoot. This footbed technology provides enhanced energy return and also sheds water efficiently. I know some runners who insert their Boomerang footbeds into other running shoes because of the feel and rebound.
The TrailFly Zero V2 and TrailFly Max both have FlySpeed Pro foam, which is different than the TrailFly Speed’s PowerFlow Pro midsole. Different shoes. Different mission. Different midsoles. The TrailFly Zero V2 doesn’t have a rockplate, but I don’t think it requires that degree of fortification. The difference between the two midsole materials is noticeable. The FlySpeed Pro offers more longevity both to an individual run and to the overall life of the shoe.
Since I stepped right into the V2 from the original after months of testing, I can confidently attest that the firm midsole comfort has remained constant between the shoes and that the integrity of the FlySpeed Pro midsole has remained steady across the miles. Although the shoe isn’t shaped to be a speed monster, the midsole supports faster miles when needed, but it also shows up for continued underfoot comfort. The low stack height still allows for decent ground control and feedback.
Inov8 TrailFly Zero V2 Outsole
The outsole of the Inov8 TrailFly Zero V2.
The Inov8 TrailFly Zero V2 comes with full coverage of the brand’s proprietary G-Grip graphene rubber outsole — a decent rival of the Vibram Megagrip. Full coverage adds weight but boosts protection and enhances long-term durability. According to the brand, they’ve enhanced the rubber’s traction for better grip on wet rocks. Since the TrailFly’s mission is rock and hardpack, this upgrade seems practical and noteworthy, and perhaps pushes it to compete with the outsoles of some VJ shoes. To be tested.
The TrailFly Zero V2 outsole wears the same layout — including lug depth — as the TrailFly Speed. At the trail interface, there are 4-millimeter multi-directional lugs, adequate for harder surfaces and moderate singletrack. The grip is notable, and again, reliable across most trail conditions and moderate weather circumstances. The outsole has seen very little wear, given the number of road miles within the shoe’s total mileage. As I noted in the Inov8 TrailFly Speed review, brands like VJ and Inov8 have found a way to enhance grip but also soften the rubber enough to make it amenable for brief road running.
Inov8 TrailFly Zero V2 Overall Impressions
A top view of the Inov8 TrailFly Zero V2.
The Inov8 TrailFly Zero V2 showed up ready to tackle the trails with a dialed-in fit and feel. Inov8 listened to feedback across the board for the TrailFly series, and designers answered with a second generation that can endure and face the hardpack life. The upper of the original really needed some fine-tuning — notably with lockdown — and they nailed it. They took a reliable and endurance-focused trail performer and enhanced its durability and overall fit.
The TrailFly Zero V2 is geared for what the brand calls True Natural Running. I have taken this to mean foot-focused, gait-supported running with heel-to-toe natural movement. This shoe design works for that, and it also supports hard-surfaced trail running — front country and backcountry — with endurance and textured terrain in mind. It has innate versatility, but shines on the daily grinds, especially if zero drop is a standard in the running arsenal.
As a foot-focused strength and conditioning coach, I support and applaud the companies that recognize natural foot biomechanics and differently shaped feet. Inov8 is a shoe company I tell my athletes and runners about all the time. Their approach to launching different versions of their base models is much appreciated.
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Call for Comments
- Have you run in the Inov8 TrailFly Zero V2? What did you think?
- Do you have any experience with other shoes in the Inov8 TrailFly line?
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