Inov8 Roadfly review

After testing the Inov8 Roadfly extensively in our lab, we’re convinced it’s an excellent choice for:

• Runners planning a transition from regular shoes to minimalist, low-drop designs—this shoe is a fantastic bridge between both worlds.
• Fans of the Inov8 Trailfly seeking a similarly agile, road-specific experience.
• Neutral runners seeking a shoe with a standard drop and an anatomical toebox—perfect for those hesitant to transition to Altra's low-drop design.

The Inov8 Trailfly falls short of expectations for those seeking a true low-drop experience. Despite being marketed with a 6 mm drop, we measured significantly more, making it less appealing for forefoot strikers. In our view, the Altra Escalante 4 is a superior choice for those ready to embrace a zero-drop geometry, and the Altra Experience Flow is a better pick for those wanting a low-drop design.

Additionally, we believe the Trailfly's weight is a concern for its low stack height. For runners prioritizing a lightweight yet cushioned ride, the ASICS Novablast 4 offers an excellent weight-to-cushioning ratio. Alternatively, the New Balance FuelCell Rebel v4 delivers an impressively feather-light design, making it ideal for those wanting a low-stack running shoe.

The heel stack measured 31.5 mm, which is relatively low by today's running shoe standards but feels surprisingly high for the Roadfly. 

Our weird feeling come partly because Inov8 lists 27 mm in their specs and partly because the shoe is positioned as a hybrid between minimalist and modern designs. At 31.5 mm, however, it leans closer to the realm of daily trainers.

The forefoot stack measured 22.1 mm, slightly higher than Inov8's stated 21 mm. We found this discrepancy unnoticeable during testing—it has an agile feel for forefoot and midfoot strikers, and unlike the heel area, perfectly aligning with the Roadfly’s purpose.

With the heel stack measuring much higher than expected, we found the heel-to-toe drop significantly exceeded Inov8's stated 6 mm. Our measurement of 9.4 mm makes the shoe less appealing to those preferring a low-drop experience.

Inov8 incorporated its POWERFLOW PRO foam, a name that suggests top speed but, in reality, is a standard EVA midsole with moderate energy return and a firm underfoot feel. Our durometer test confirmed this with a 26.0 HA score.

We believe this firmer setup is a good idea for the Roadfly. A softer midsole could introduce instability and increase the risk of bottoming out, especially for forefoot strikers. However, we think there’s room for improvement—incorporating a modern nitrogen-infused foam could be beneficial, significantly reducing the shoe’s weight.

Through our evaluation in a 20-minute freezer test, we discovered the POWERFLOW PRO foam retained much of its resilience, softening by only 18.8%. Nice result!

The BOOMERANG insole stands out as a unique feature, setting the Roadfly apart from most daily trainers. Instead of the average 4 or 5 mm EVA insole, Inov8 opts for a thick 7.2-mm TPU footbed—an advanced material designed to enhance energy return more effectively than typical insoles.

This Boost-like insole significantly elevates cushioning, particularly benefiting forefoot strikers who enjoy improved comfort in the front of the shoe.

As textbooks suggest, low-cushioned shoes should avoid rockered soles, and Inov8 made the right choice with the Roadfly. It delivers a natural ride that encourages foot strength, and that makes it an ideal partner for those transitioning from regular shoes to barefoot designs.

By the way, this photo perfectly highlights the significant role of the insole in cushioning this shoe—it’s absolutely massive!

Using our caliper, we measured the Roadfly's toebox at 100.9 mm at its widest point in the standard D width. In our experience, this measurement makes it one of the most wide-foot-friendly options we’ve tested recently.

Additionally, Inov8 offers a wide size in select markets, further enhancing its appeal for those with broader feet.

The upper height on the Roadfly is relatively low, and in our experience, runners who often struggle with low-volume uppers might feel some discomfort despite the stretchy mesh attempting to offset this limitation. Of course, runners who thrive in snug-fitting uppers will feel the opposite.

The toebox design is anatomic, barely tapering towards the big toe. Our caliper measured a substantial 89.2 mm width in our second measurement point, providing a spacious fit that allows unrestricted, Altra-like toe splay.

The Inov8 Roadfly is a 100% neutral running shoe that we don’t recommend for runners with even mild stability needs. In our experience, its narrow platform and super-flexible design—despite being low to the ground—demand a well-centered stride.

The Roadfly demonstrated moderate resistance when we bent and twisted it during our tests, earning a 3 out of 5 on our torsional rigidity scale. In our view, this well-balanced flexibility suits its versatile, walk-to-run design.

The heel counter leans toward the flexible side, and after testing, we rated it 2 out of 5. In our view, Inov8 nailed the balance for those seeking a transition shoe between stiffer regular trainers and minimalist designs with ultra-flexible heels.

From the moment we unboxed the shoe, we appreciated its streamlined design, a refreshing contrast to the bulky, maximalist models we’ve recently tested in the lab, like the PUMA MagMax Nitro or the Hoka Skyflow.

With a forefoot measuring just 111.6 mm, it undeniably demands 100% neutral running form but rewards with a dynamic, agile, and fun ride.

The heel enhances the nimble design, measuring just 83.8 mm with our digital calipers. However, this ultra-slim, competition-like heel design compromises stability in the rear—something potential buyers should consider. Therefore... heel strikers, proceed with caution!

The Roadfly flexes effortlessly, requiring just 20.6N to bend it to our standard 90-degree test point. This makes it fantastic for everyday activities like walking the dog, picking up the kids, grocery runs and, naturally, daily running!

The Inov8 Roadfly qualifies as a lightweight shoe at 8.9 oz or 251g, but in our view, it could be lighter given its size.

In fact, we believe a reduction to around 8 oz or 230g would be an interesting goal for version 2. However, in our experience, the current design prioritizes outsole durability—a trade-off we appreciate over shaving off a bit more weight. Maybe it just needs a new supercritical foam!

At first glance, the upper of the Inov8 Roadfly might resemble that of a cheap running shoe, but as soon as we put it through rigorous testing, its true quality became clear. 

In terms of breathability, the toebox exceeded our expectations. Using our smoke-pumping machine, we pushed the limits, and the results were outstanding. Smoke flowed through the toebox with ease, earning it a perfect 5/5 in ventilation.

Next, we tested the upper’s structure by moving it over a powerful LED light. This revealed Inov8's clever design strategy: while the toebox maximizes breathability, the rest of the upper is thicker and prioritizes stability and durability.

Under the microscope, we observed a dual-layer engineered mesh in the toebox, designed with countless ventilation holes.

Unlike other shoes that compromise airflow with thick inner layers, Inov8 opted for a thin layer. Additionally, we discovered a reinforced toe area—perfectly suited for easy trails or gravel roads—highlighting its versatile design.

To test the Roadfly’s toebox durability, we applied our Dremel at 5K RPM with 3.2N of force. Sadly, it scored just 1/5—highlighting significant room for improvement.

The heel performed slightly better, scoring a 3/5—not exceptional but far from problematic.

We believe this is crucial, as many will use the Roadfly for walking or gym workouts on top of running, where heel durability often faces greater challenges.

Moving to the outsole, we had high hopes inspired by the Inov8 Trailfly’s impressive performance. True to its DNA, the traction exceeded expectations, reinforcing Inov8’s reputation for crafting grippy outsoles.

Despite the firm 83.5-HC rubber—typically less effective for grip—the full-length ground contact compensates brilliantly. All in all, we were impressed by its reliable traction, which felt secure and stable across a variety of surfaces.

It’s rare to find outsoles that balance excellent grip with standout durability, and while the Roadfly excels in the former, it falls short in the latter. After testing, we discovered a 1.5-mm dent from our Dremel, which underperformed compared to most road running shoes.

Although our Dremel test showed more wear than anticipated, we found the 3.8 mm rubber thickness and extensive full-length coverage balance the result with ease.

Having more outsole in contact with the ground allows forces to distribute more evenly, which isn’t reflected in our Dremel test. On the other hand, it's worth noting that the full-length rubber coverage and generous thickness add significant weight to the shoe, so this feature doesn't come without a major trade-off.

Aiming to rival daily trainers like the Nike Pegasus 41, Inov8 priced the Roadfly within the low range for this category, and we believe it’s a fair deal. The shoe is well-crafted, offers compelling features like an anatomic toebox, and impressively, they also managed to trim over 10% off the Trailfly’s price.

The Roadfly includes reflective elements on both the rear and front, which we found interesting for visibility in low-light conditions.

The tongue is generously padded, delivering a plush instep feel that we found excellent for those who value comfort and secure lace knots. However, we believe a slimmer, weight-saving tongue would better suit the Roadfly's moderate stack height. Maybe around 5 or 6 mm!

The tongue is sewn to the sides of the midsole—a snug-fitting design choice that we believe enhances both fit and comfort. That's nice, as this feature is especially essential for a shoe with such a spacious toebox.

The heel includes a convenient finger-loop tab, making it effortless to slip the shoe on daily. Plus, it adds a premium touch that elevates the overall look.

Those seeking extra room in the upper or aiming to reduce cushioning and stack height can easily do so, as the BOOMERANG insole is removable. Simply swap in a thinner footbed, and make sure it aligns well with the Roadfly’s foot-shaped toebox.