Nike Zoom Fly 6 review

After testing the Zoom Fly 6 in the lab and on runs, we believe that:

• It's interesting for runners not yet ready to commit to a supershoe who are seeking a blend of performance and comfort.
• Those who disliked (or hated!) the bulky Zoom Fly 5 will love the Zoom Fly 6's lighter build, superb cushioning, and responsive feel.
• It's ideal for runners seeking an reasonably-priced, durable alternative to a supershoe, offering a similar ride but built to last.
• Could be perfect for those in need of a single shoe capable of daily runs, speed sessions, and even race-day performance.

We believe the Zoom Fly 6 makes significant improvements over its predecessor, but it still has limitations that could deter some runners. In our view, the snug toebox could be a major drawback for many. For a roomier option, we recommend the Mizuno Neo Vista, featuring an accommodating toebox and a stretchy knit upper that comfortably adapts to your feet.

Additionally, we found that the streamlined shape of the ZF6 reduces its stability, which may concern runners seeking a more supportive ride. If stability is a top priority, the ASICS Superblast 2 is an excellent alternative with its world-class support. And for those less concerned about weight, the Hoka Skyward X offers a balanced and durable option with plenty of cushioning.

In our opinion, a key requirement for a supertrainer is a notable stack height of around 40 mm to truly deserve the title, and Nike delivered. They officially claim 40 mm at the heel for a World Athletics-legal height, and our measurement came remarkably close at 39.7 mm.

With such a towering stack height, this shoe effortlessly covers all the long-distance spectrum—handling everything from demanding long runs to marathons.

The forefoot meets another benchmark we believe is essential for a supertrainer—crossing the 30 mm mark in stack height. Our calipers measured 30.1 mm in the forefoot, just edging past this threshold.

This measurement highlights another important takeaway—regardless of your footstrike, the Zoom Fly 6 provides abundant cushioning to support all running styles. However, there's a significantly higher concentration of ZoomX in the forefoot compared to the heel.

The heel-to-toe drop measured 9.6 mm here in the lab—a touch steeper than Nike’s claimed 8 mm.

In our view, this slightly elevated difference might be a dealbreaker for some forefoot strikers, yet remains consistent with the brand's feel.

The Zoom Fly 5 left many of us disappointed, mainly due to its excessive weight and Nike’s use of recycled (Next Nature) ZoomX foam, which offers significantly less energy return than standard ZoomX. Fortunately, version 6 corrected this.

Our initial durometer measurement showed the foam at 16.1 HA, delivering an explosively bouncy feel with a touch of plushness—not overly soft but perfectly balanced and energetic. It impressed us with its responsive performance during testing.

Notably, the sixth iteration marks the first Zoom Fly to feature real ZoomX foam. Previous versions either relied on the Next Nature (recycled) variant or React foam.

The Zoom Fly 6 isn’t 100% ZoomX. Like many supertrainers, it combines a high-performance foam with a secondary material placed closer to the ground—offering extra durability and support while preserving ZoomX’s standout properties.

That secondary material is SR-02, an EVA-based foam that Nike previously used in many shoes like the Vomero 17. Interestingly, it scored the same 16.1 HA durometer reading as ZoomX in our tests.

In our opinion, this approach aligns with the Zoom Fly series' role as the durable training companion to Nike’s supershoes. Using only ZoomX might not have been feasible for maintaining the shoe’s $170 price point while ensuring its longevity.

Aside from its world-class energy return, another hallmark of Pebax-based foams is their highly-resilient performance under cold conditions, maintaining its softness. The Zoom Fly 6 demonstrated this by hardening only 6% after spending 20 minutes in our freezer.

We discovered a 3.0 mm thin insole resting atop the foam, highlighting that this shoe is designed with a strong focus on performance.

The Zoom Fly once held the reputation of being a "budget-friendly" Vaporfly, especially during the era of the Zoom Fly Flyknit—a shoe fondly remembered by many of us.

That said, this Flyplate it’s not the same plate as the one featured in the Vaporfly 3. While the forefoot design closely resembles it, the midfoot and heel sections have been tweaked to favor slower paces and deliver smoother, more forgiving transitions.

We found that Nike crafted a moderately pronounced forefoot rocker, rising up to 4 cm. In our experience, this well-balanced design excels during fast-paced long runs or tempo workouts, offering smooth yet snappy transitions.

If you're a regular at RunRepeat, you probably know how much we love diving deep into running shoe foams, and ZoomX remains one of the most fascinating materials we’ve encountered—it was, after all, the original superfoam.

We’ve already mentioned before that this ZoomX is not the boring Next Nature variant. But is it the same top-tier ZoomX used in the Alphafly or Vaporfly?

Through our evaluation using a digital microscope, we confirmed that the Zoom Fly 6 features the same ZoomX formulation found in other Nike trainers like the Invincible 3 and Pegasus Plus, which is not the one featured by the Alphafly 3. This variant trades a bit of energy return for improved durability, striking a mix of responsiveness and longevity.

We created a precise gel mold of the toebox to determine the exact space inside the Zoom Fly 6.

From our first measurement, we recorded a mere 90.9 mm at the upper's widest part. This design caters perfectly to runners with narrow feet, but others will need to appreciate snug-fitting uppers to feel comfortable. It’s among the most compact toeboxes we've measured in the lab!

The trend persists in the big toe area, measuring just 72.6 mm in width. This narrow design reinforces Nike's intention to position the Zoom Fly 6 as a cheaper racing shoe, offering a secure fit in the toe area.

Vertical clearance for the toes is equally limited, measuring just 24.5 mm.

In our view, those who prefer a more relaxed and less snug experience should avoid the Zoom Fly 6.

With its nearly 40-mm stack height and compact dimensions, the Zoom Fly 6 offers surprising stability—thanks to the carbon plate, supportive midsole sidewalls, and a heel flare that takes its design from the Alphafly 3. That said, this is 100% neutral running shoe, and we don't recommend it for anyone with stability issues.

With a carbon-fiber plate sandwiched between two foam layers, it’s no surprise that bending or twisting the shoe was impossible—a clear 5/5 on our scale!

The heel features a highly-structured design, earning a 4 out of 5—an intentional shift away from the ultra-flexible heels typical of most supershoes. This highlights the shoe’s hybrid nature, blending racing performance with daily trainer support.

We mentioned earlier that this shoe has compact dimensions—and we meant it. From the first step, it felt agile and streamlined, completely avoiding the bulky nature of many supertrainers.

Using our calipers, we measured the forefoot at just 111.9 mm—a narrow result that falls below the average for running shoes.

The same design approach continues in the heel, measuring just 87.9 mm. For this reason,  heel strikers who tend to land slightly off-center may find that the Zoom Fly 6 doesn’t provide the best support for their stride.

As we mentioned earlier, this shoe feels like a blend of a supershoe and a daily trainer, and here’s further evidence: despite the carbon-fiber plate, it’s not extremely stiff, scoring just 35.5N in our 90-degree bend test.

This makes the ZF6 more suited to slower paces compared to stiffer alternatives, and a bit less extreme for racing.

The Zoom Fly 5 disappointed many runners because it was heavy, weighing 9.85 oz (280g), mainly due to the Next Nature ZoomX variant and other design choices. Thankfully, Nike improved the Zoom Fly 6, reducing the weight to 8.75 oz (248g), making it much lighter and easier to run in.

Nike designed the Zoom Fly 6 with comfort in mind, incorporating generous padding in the heel and a thick, plush main layer. While this approach enhances the luxurious feel of the shoe, it also limits airflow, earning a moderate 3/5 breathability score in our lab tests.

For most climates, this is adequate, but in extremely hot conditions, we recommend pairing the shoe with ultra-thin, moisture-wicking socks, especially for longer runs.

When examining the upper under an LED light, we found that Nike focused ventilation on essential areas, including the toebox, midfoot, and tongue. This targeted approach ensures airflow in key zones while maintaining structure in the rear of the shoe.

Using a microscope, we discovered the upper’s unique construction—a thick, durable mesh layer supported by an ultra-thin, transparent top layer. This rare combination adds some strength without significantly increasing the shoe’s weight.

We also discovered an interesting detail on the upper—Nike added a small reinforcement to prevent holes from forming.

Whether this was a deliberate feature or a late fix is unclear, but it’s a welcome addition for runners prone to that issue, offering a nice durability boost in this critical spot.

To put the upper to the test, we fired up our Dremel and subjected the material to our usual stress test, ready to see how it would hold up against simulated wear and tear.

The results were outstanding. In our experience, very few running shoes achieve a top-tier durability score, and the Zoom Fly 6 excelled earning a perfect 5/5.

The heel continued the impressive performance streak set by the toebox, earning another flawless 5/5 in our tests. This extraordinary durability is rare to find and makes the Zoom Fly 6 a supertrainer perfect for runners who frequently wear out their uppers.

After setting an impressive standard in terms of durability with its plush yet durable upper, we turned our attention to the outsole. Using our durometer, we measured its hardness at 82.0 HC—a well-balanced result better suited for training than racing.

We found impressive rubber coverage, with only the midfoot and a small section of the forefoot exposed—an intentional design choice aimed at reducing weight.

Returning to durability, the outsole performed well—surpassing the average—though not quite reaching the excellence of the upper. Still, we were satisfied as it showed only a minimal 0.8-mm dent during testing.

Our final outsole measurement focused on rubber thickness, which came in at 3.2 mm—a surprising result that felt even a bit excessive for a hybrid shoe built for both racing and training. 

In our view, reducing this to 2 or 2.5 mm, given the rubber's good durability, could offer weight-saving benefits and a more responsive feel while maintaining adequate longevity.

In our opinion, the Zoom Fly 6 offers great value for a supertrainer. Its MSRP is even lower than the Nike Pegasus Plus—a surprising detail we appreciated when we purchased this pair to test in our lab!

Nike added reflective elements, a feature that enhances safety during nighttime runs and is always a welcome detail we appreciate.

One of the main features that makes the Zoom Fly 6 comfortable is the tongue. While many supertrainers often skimp on tongue padding, Nike invested some weight here and designed a 6.1-mm tongue—more typical of a daily trainer.

This provides great comfort for long runs, even lasting over two hours. However, those looking for the ZF6 primarily for racing may prefer a thinner 3 or 4-mm tongue to keep the shoe lighter and more responsive.

We found a semi-gusseted tongue, our favorite design for performance-oriented shoes—it enhances lockdown while adding minimal weight.

One of the few carryovers from the Zoom Fly 5 is the absence of a heel tab, and we have no complaints about it.

The thin stock insole is removable, but we don’t think swapping it is a good idea for most runners. The shoe already has limited vertical space in the toebox, and a thicker replacement would make the fit uncomfortably cramped.