Nike Streakfly 2: análisis y review

We had a lot of fun testing the Nike Streakfly 2 and can recommend it for:

• Runners seeking a super-fast shoe to race the mile, 5K, or 10K at blazing-fast speeds, and even half marathons if they're lightweight.
• Fans of old-school racing flats who want a modernized feel with today's technology and a carbon plate, in the best fusion we've ever seen to date.
• Those disappointed by the original Streakfly, as it lacked the speed needed for true racing. That's now completely fixed.
• Forefoot strikers focused on 5K and 10K races who need a supershoe for intervals and competition.

We believe that the Streakfly 2 falls short for those aiming at longer distances like half marathons or marathons. From our perspective, other supershoes from Nike like the Vaporfly 4 or Alphafly 3, although pricier, are better picks for those events.

Additionally, we are convinced that the ultra-narrow toebox and spike-inspired low-drop geometry limit the Streakfly 2's appeal for many runners. Heel strikers should opt for the Adidas Adizero Takumi Sen 10 for its higher-drop geometry, while those needing more room will find the New Balance FuelCell SuperComp Pacer v2 far more comfortable.

It's clear to us that Nike wanted to better reposition and differentiate its range of supershoes, and now everything makes much more sense. Just look at the stack height in the heel:

• Nike Streakfly 2: 27.0 mm
• Nike Vaporfly 4: 34.1 mm
• Nike Alphafly 3: 38.1 mm

Depending on how much cushioning you want, how far you plan to run, or simply how much ground feel you prefer, Nike now has you covered. Previously, the line was much blurrier between the three shoes, as the original Streakfly had 31.7 mm.

Naturally, with 27.0 mm underfoot, you can expect a super-direct, feedback-rich ride that feels miles away from the traditional supershoe experience of recent years.

The forefoot also measures quite thin at 23.3 mm, but compared to the heel, it's actually really close to the average. In our view, this shoe is simply built for those seeking a direct ground feel. We believe this is a shoe that truly rewards raw speed—not just relative to your fitness level, but in an absolute sense. The faster you run, the better the Streakfly 2 feels underfoot.

In fact, we think that this is the closest a road shoe has been to a track spike—both in its aerodynamic shape, low weight, and fast-reacting feeling. It reminds us a lot of the Nike Dragonfly 2 Elite, which is Nike’s top spike for 3000, 5000, and 10000 events, and we believe owners of that shoe will love the SF2 for training.

While most Nike supershoes feature a mid or high drop, the Streakfly 2 breaks away from that trend with a spike-like low drop of 3.7 mm. We believe it’s much better suited for runners with a midfoot or forefoot striking technique, and we take no responsibility for any heel striker choosing the SF2...

Another huge letdown from the original Streakfly was its ZoomX foam. As we explained in our guide about running shoe foams, brands use different formulations under the same name. In the Streakfly v1, the ZoomX was not the top-tier one found in supershoes, but a training-focused version that was more long-lasting but delivered less energy return.

After complaints from every corner, Nike changed course and gave us the real deal in the Streakfly 2, as we proved by observing both foams under the microscope. See the differences? The one in the SF2 matches the supercritical Pebax used in the Nike Vaporfly 4 and Dragonfly 2, and that's exactly what we want for pure performance.

In terms of energy return, it’s extremely good. In this version, Nike made it slightly softer than in other supershoes at 16.4 HA, reinforcing the ground feel and proprioceptive-focused ride of this shoe.

The Streakfly 2 follows the original supershoe recipe by using two slabs of foam with a carbon plate nestled in between, and the secondary layer of ZoomX delivered a similar result of 17.4 HA.

We put the Streakfly 2 in our freezer for 20 minutes, and it came back 20% firmer. That’s a good result, although not outstanding for a Pebax foam.

The insole is thinner than average at 3.0 mm, highlighting how Nike wanted to maximize the ZoomX foam experience given the low stack height—and we’re all for it!

The Streakfly 2 features a unique shape that feels much closer to a track spike than a regular running shoe, rewarding a clean forefoot strike. Basically, landing in the back half of the shoe means you won’t get the magic of this shoe.

However, the forefoot curvature of this shoe is simply wild, delivering an exhilarating ride that feels fantastic for mile, 5K, and 10K events. It just propels you forward if you land in the right spot.

Another major omission from the original Streakfly was the plate. Nowadays, you simply can't sell a race-focused 5K/10K shoe without a full-length carbon plate for that explosive-energy ride most racers expect.

Luckily, Nike fixed that in version 2, though the shape of the so-called Flyplate changes slightly compared to the Vaporfly and Alphafly designs, again reinforcing a forefoot strike.

We already mentioned a few times that this shoe feels like a track spike for road running, and here we found further proof of it thanks to our super-precise gel test for the toebox.

From the very first moment we tried the shoes, they felt snug-fitting and clearly built for short, fast efforts. Our testing confirmed these first impressions: just 89.7 mm in the widest part of the upper!

The second measurement of 66.7 mm was even more revealing.

The Streakfly 2 has a super-snug fit to unlock maximum speed, but forget about any natural toe splay. It’s not designed for that, and we believe that even running a half marathon in these is like the absolute limit for most runners.

Unsurprisingly, the height of the toebox is extremely restricted at 23.1 mm.

All in all, it’s clear that this is one of the lowest-volume uppers we’ve ever analyzed in the lab, with limited room both vertically and horizontally. On the flip side, for runners with small, narrow feet or those who love a glove-like upper, it feels amazing.

The Nike Streakfly 2 feels like a radical throwback compared to any modern running shoe or average daily trainer launched in the last few years.

The midsole is narrow, there are no sky-high sidewalls, and no stability-driven features at all. In our view, if it wasn’t for the carbon plate, the shoe would be impossible to enjoy—now it’s just wild, but fun too!

Despite featuring a carbon-fiber plate, the massive midsole cutout and low stack height deliver surprisingly low torsional rigidity, scoring a 2/5 on our scale.

The heel counter feels remarkably similar to those found in track spikes, scoring a 1/5 in our manual test. It lets your body handle the stabilization, making the ride ultra-natural and fun—but also more demanding.

You probably already guessed how insanely narrow this shoe is based on our previous photos, right? Nike basically designed a go-kart that devours sharp corners and loves flat-out accelerations.

After using our precision calipers to get the real numbers, we discovered 102.2 mm, confirming this bold design.

If you were impressed by the forefoot, wait until you see the heel. At 70.8 mm, it’s (at the time of this review) the narrowest road running shoe we’ve ever measured in the lab.

We really applaud Nike because, with the Alphafly and Vaporfly already covering other needs, there was space to create something wild, and they delivered. However, again, we strongly advise against this shoe for heel strikers.

The incredible flexibility of this shoe really surprised us in the lab. Despite packing a carbon plate, the super-low stack height, the narrow midsole, and the huge central cutout let the shoe flex easily. In fact, we only needed 7.0N to move it to 30º.

But if there's a defining feature of the Streakfly 2, it’s the ridiculously low weight. When we held it after unboxing for the first time, we thought it was crazy how light it felt, and we put it straightaway on our digital scale.

At 4.5 oz or 128g, it’s almost a miracle. It’s lighter than most track spikes on the market and way, way lighter than most supershoes. It basically disappears on your foot, and if you love this barely-there sensation for a 5K or 10K, Nike finally delivered exactly what you were asking for.

For context, the previous version of the Streakfly was already a lightweight shoe at 6 oz or 171g!

From the moment we got the Streakfly 2 in the lab, we knew it would deliver top-tier ventilation. The shoe is so focused on being as feather-light as possible that there was no doubt in our minds it would ace our smoke test—and indeed, it scored a perfect 5/5.

When we inspected the upper by shining a LED light through it, we were amazed by how breathable it looked. Not just the toebox, but nearly the entire upper feels ultra-airy, confirming the complete absence of support features or midsole sidewalls.

Under our microscope, we discovered that the engineered mesh used by Nike differs from the Vaporfly’s design and is totally distinct from the Atomknit found in the Alphafly. Feels a bit cheaper, which makes sense given the much lower price tag of the Streakfly 2.

Yet, it does a superb job when it comes to airflow, letting your feet breathe during fast-paced runs.

Oh, and please don’t expect any comfort-driven features here. Aside from a modest amount of padding in the heel area, everything else is clearly optimized for performance and extreme weight savings.

The upper breathes like crazy, but it comes at the cost of low durability. However, this relationship is pretty common—in the lab, we often find that ultra-airy uppers surrender quickly to our fast-spinning Dremel and earn a 1/5.

That said, we believe this is not a shoe meant for daily training or rough-terrain running, so durability concerns are less alarming here compared to other models.

The heel padding was a more important test for us, and fortunately, the Streakfly 2 delivered a solid performance at 4/5. No concerns at all in this area.

The outsole of the Streakfly 2 follows the average supershoe layout, with the forefoot well covered, an exposed midfoot, and a barely-protected heel that favors a race-day build over daily use.

We measured the hardness of the forefoot rubber at 63 HC and the heel at 43 HC, which really helps to achieve nice grip. From our testing, these soft numbers clearly suggest that you shouldn’t expect it to last forever. It's just not made for that.

So, how does such soft rubber perform in terms of durability? Let's find out with our Dremel test. The result was, as expected, worse than average due to the soft rubber formulation. But at 1.7 mm, it's not dramatic—we actually expected something much worse!

The outsole measures 2.4 mm in thickness in the forefoot.

It’s probably the only area where we see real potential for weight savings—maybe Nike will go all-in on that for version 3 too.

The price tag of the Streakfly 2 feels like a two-sided story. On one hand, we feel it's fair for offering superfoam and a carbon plate in such a feather-light package. On the other, some might find it pricey given its limited distance range and thin cushioning, and it also features a small increase from version 1. Which side are you on?

We found zero reflective elements in the Streakfly 2—which is exactly what we expected anyway.

The tongue is ridiculously lightweight, and it's the thinnest we’ve ever measured at the time of this review at 0.4 mm. That’s hugely impressive because we’ve tested hundreds of shoes here in the lab.

It clearly shows how Nike pushed for an ultra-stripped-down design to make the shoe as feather-light as possible. Oh, and the lacing system surprised us too—we expected something similar to the Vaporfly 4 but instead found a wire-based setup instead of the usual punched eyelets.

To keep the weight as low as possible, Nike decided not to attach the tongue to the sides, saving a few grams in the process. While that often leads to some shifting, the lockdown is so snug and race-ready that it’s unlikely you’ll feel it.

The heel features a pull tab that’s more about style than function. Still, it looks great, almost like a sleek little flap on a race car.

We were genuinely surprised to find that the Streakfly 2 doesn’t feature a removable insole, especially considering the Vaporfly 4—developed alongside it—does. It’s a curious choice, given how much the two shoes otherwise share.