Inov8 Trailfly Speed v2 review

The Inov8 Trailfly Speed v2 sounds like a good choice for:

• Those with wide feet looking for a roomy, natural fit that allows the toes to spread comfortably.
• Anyone tackling short, fast trail runs on dry, hard-packed terrain where its low stack and strong ground feel can shine.
• Hikers that go for the occasional run and prefer a flexible shoe with a close-to-the-ground feel and plenty of connection with the terrain.
• Runners who prioritize nimble handling and solid durability over maximum cushioning and energy return.

If you have narrow feet, the Inov8 Trailfly Speed v2 probably won't work for you. Instead, we suggest going for the Xero Shoes Mesa Summit.

We also think heavier runners might be better off with a bit more cushioning underfoot. The Inov8 Trailfly v2 is the obvious option here, while the Topo Terraventure 5 is another excellent choice that combines extra cushioning with durable Vibram rubber.

Inov8 positions the Trailfly Speed v2 firmly in the low-stack category, which usually comes with moderate shock absorption.

Our 97 SA result in the heel and 76 SA in the forefoot clearly confirms that, and we find it refreshing for runners seeking a shoe that goes against the market's current trend toward higher stacks and more cushioning.

We measured 57.1% in the heel and 60.5% in the forefoot, putting the Powerflow Pro foam in a fairly average range among trail shoes. In our opinion, we expected a little more from a shoe at this price point.

As we noted when discussing shock absorption, Inov8 positions the Trailfly Speed v2 firmly in the low-stack category, with a thinner midsole than the non-Speed version.

We measured 25.5 mm in the heel, making this shoe an excellent choice if you dislike maximalist designs and prefer a closer-to-the-ground ride. And that's what we felt using the Trailfly Speed v2: a low-riding setup that delivers a more natural, connected feel.

The forefoot sits well below the current lab average, and we carefully measured it at just 20.1 mm. It's more than a minimalist shoe, but it certainly qualifies as low stack in our assessment.

The regular Trailfly v2 has a higher drop than the Speed variant. Inov8 states a 4 mm drop, while we measured 5.4 mm, giving it a mid-drop setup that feels remarkably similar to Topo Athletic shoes.

Another feature that clearly sets the Speed variant apart from the regular Trailfly v2 is its foam. This version uses a much firmer compound, which may be a smart design choice given the low stack height and the need to prevent excessive compression.

However, Inov8 may have gone a little too far with this iron-firm foam, which we measured at 54.0 AC. For runners who prefer a softer feel, this could be a deal-breaker. In our assessment, something in between, around 40-45 AC, would have been a more balanced choice.

At least when we put it in the freezer, it only became 10% firmer, which is a very positive result compared to most other trail shoes.

We noticed that Inov8 has preserved its familiar non-rockered geometry, giving the Speed v2 a natural feel that perfectly complements its low-stack design. And makes it excellent for walking long distances too.

Inov8 fans usually expect their signature anatomical fit, which allows the toes to spread naturally. We wanted to see whether version 2 of the Trailfly Speed could maintain that same roomy design.

Our first measurement is already well above the lab average at 100.3 mm, which is excellent news for those seeking excellent toe splay.

Then we moved our calipers to the toebox area and found another above-average result of 79.7 mm, further confirming the wide-foot-ready design.

At the same time, keep in mind that this generous width may feel too roomy for runners with narrow feet.

The toebox height measured 25.9 mm, falling a bit below our current lab average, but that's not particularly surprising given how closely the design mirrors the regular Trailfly v2.

The vertical space is just right for a trail shoe, providing a secure fit while still leaving enough room to wiggle a bit your toes.

Traction is adequate, with a coefficient of friction of 0.62 in our SATRA TM144 test. 

That's a decent result that makes the shoe a safe pick for dry conditions, which are clearly its preferred terrain. However, wet surfaces are a different story with the Trailfly Speed v2, and you'll see why next.

The 3.5-mm lug depth and tightly-spaced layout clearly suggest that the Trailfly Speed v2 is designed primarily for gravel roads and easy terrain.

In our assessment, it's best suited to dry conditions rather than technical trails or soft, wet ground, where the shallow, closely-packed lugs are less effective.

We appreciated how the Graphene Grip rubber covers the entire outsole, leaving no exposed foam whatsoever. We also liked the huge flex grooves, especially the prominent horizontal groove in the forefoot, which helps give the shoe its flexible feel.

Speaking of flexibility, our lab test confirms just how flexible this shoe is. After bending it to 30 degrees, we found that the Trailfly Speed v2 required only 8.6N of force, one of the lowest readings we've ever recorded in the lab.

That's excellent news for runners who dislike stiff shoes and want a highly-flexible design that also works well for all-day hikes.

While the flexibility result was excellent news for the Inov8, the weight measurement was a different story. The Trailfly Speed v2 tipped our scale at 10.1 oz (286g), which is surprisingly heavy for such a low-stack shoe and even makes it heavier than the regular version, likely due to its denser foam.

For a shoe with Speed in the name, we believe this extra weight is a significant drawback.

One of the main benefits of a lower stack height is improved stability, and that's exactly what we experienced with this shoe compared to the regular version.

This becomes even more noticeable when leaving smooth, predictable terrain behind, as the low-stack design handles unexpected changes in the ground, such as roots and channels, with greater confidence.

When we unboxed the Inov8 Trailfly Speed v2 and manually twisted it to get a first impression of its rigidity, we immediately noticed how little resistance it offered.

Our custom lab machine confirmed that initial assessment, with a torsional rigidity score of just 10.5 Nm, well below the average.

We found the heel counter to be moderately stiff, scoring 2/5 in our manual test. This provides a good balance between structure and flexibility though leaning more towards the latter, and it keeps the heel secure without making the rear feel overly rigid.

Besides the firmer, denser foam, the wider forefoot is another reason the Trailfly Speed v2 weighs more than the non-Speed version.

We measured 118.6 mm in the forefoot compared to 111.0 mm in the regular model, and that extra width clearly contributed to the stability boost we noticed during our runs.

The heel is also noticeably wider on the Speed v2, measuring 87.8 mm compared to 83.3 mm on the regular version.

The toebox durability is outstanding, earning a perfect 5/5 in our test.

On top of that, the Trailfly Speed v2 comes with plenty of protection, with strong KPU overlays replacing the 3D-print overlays from the first generation. These new overlays provide excellent protection and makes the upper an exceptionally tough area of the shoe.

The heel padding also performed very well in our durability test, scoring 4/5. Therefore, this is a durable, hard-wearing area that should hold up well to repeated use on the trails.

The Graphene Grip rubber performed well in our outsole durability test, with just 0.9 mm of wear after abrasion.

Inov8 uses a 1.7 mm-thick rubber layer, which we believe is more than sufficient for the dry, easy terrain this shoe is designed to handle.

The BOOMERANG insole is noticeably thick, measuring 7.2 mm. This extra material adds a welcome layer of cushioning underfoot and accounts for almost half of the midsole height.

You can remove it and replace it with a thinner insole, making the Inov8 Trailfly Speed v2 even lower to the ground. However, you'll also lose the extra pop that the BOOMERANG insole brings to the ride, which is clearly noticeable, as most third-party insoles simply can't match it in that regard.

The Trailfly Speed v2 has no reflective elements whatsoever.

While many parts of the shoe remain similar to the regular version, the tongue is a notable exception. Inov8 completely redesigned it, and we found that it feels more premium and refined than before.

However, the redesign comes with significantly less padding. At just 2.9 mm thick, the tongue is very thin and also relatively short, which may not appeal to runners who prefer a more substantial, generously padded design.

The tongue features a semi-gusseted design that works well. That said, we wonder why Inov8 went to the trouble of matching every other component in blue, only to leave this fabric in white.

Small details matter, especially when you're suggesting an MSRP not far away from $200...

The finger-loop heel tab is a cool addition that makes the shoe easier to put on showcasing the Inov8 branding.

The Inov8 Trailfly Speed v2 comes at a $10 premium over the regular model, making its value proposition somewhat bittersweet. Some features are genuinely impressive, but others fall short of what we'd expect at this price point.

In our opinion, waiting for a decent discount is probably the smartest way to get the most value from this shoe.