Article by Bryan Lim
Nike Streakfly 2 ($180 / AUD 250)
Introduction
With all eyes on the release of the Vaporfly 4 (VF4), it is not surprising that its little sibling the Streakfly 2 (SF2) has gone a little unnoticed. But this should not be the case as it has been completely redesigned from its predecessor which was released a full three years ago. A lot can and has happened in that time for both the Streakfly lineage and also the plated shoe scene. The SF2 now sees a decreased stack height from 32mm to 27mm and a decrease in drop from 6mm to 4mm, and the introduction of a full length carbon fibre FlyPlate. Essentially what we have is a trimmed down VF4.
The plated shoe scene is now ever more saturated; some say the VF4 is no longer a marathon shoe and would be great for a 5k up to a half, whereas the intended purpose for the Streakfly would be for a 5k. On the other side of the fence, Adidas has adopted a different philosophy with the less aggressive Takumi Sen 10 (and soon to be 11) for shorter distances and the Adios Pro 4 which is capable of most distances up to the marathon and possibly beyond, occupying the space that the VF4 and Alphafly 3 take up (discounting the illegal Prime X of course). Without having worn the original Streakfly, my contention is that the SF2, and contrary to ‘‘road racing’ printed on the midsole, is a great track shoe and is only more suited for elite road runners to race in.
Pros:
Ground/track field, if desired
The updated engineered mesh upper offers incredible lockdown
Feels extremely light on the foot
More forgiving than most spikes
Phenomenally grippy outsole
Cons:
A very specific shoe that is often not required in a rotation, i.e. lacking in versatility
Harsher than most other road shoes
Limited to forefoot strikers
Durability (likely)
Stats
Spec Weight: Mens 8.5 4.44 oz / 126 g
Sample Weight: Mens US9 , 4.44 oz / 126 g
Stack Height: Heel – 27mm, Forefoot – 23mm (4mm drop) (reduced from 32/26, 6mm drop )
I would like to note that my measurement of the forefoot and heel both come in at 30mm.
Platform Width: 70 mm heel / 62 mm
(tapering to 41mm which is the width that contacts the ground) midfoot / 99 mm forefoot)
First Impressions, Fit and Upper
My first impression of the SF2 was fear, and fear that I would not be able to do good enough to bring out the best in the shoe! Fears aside, it is apparent how aggressive they are when putting them on. You feel some of the softness in the ZoomX foam, but the structure created by the plate and aggressiveness of it is immediately apparent. You will also note that the SF2 appears to have a close to a zero drop (see foot away from the camera in the image above, and the below image) and I believe the claimed 4mm drop is for when the shoe is in its intended ‘racing state’, i.e. titled forwards on the forefoot. Further and as noted, my measurement of the fore and rearfoot come in at 30mm, which could also be a reason for the visual appearance that the SF2 does not have a drop.
The fit is absolutely perfect and true to size for me. I would note that the toe box width may be restrictive for some, but the overall length and width in my size provided the perfect fit. In the image, my index finger points to where my big toe bulges slightly over the width of the platform, and does so even without socks on. The upper is forgiving enough such that even with this, there were no hot spots or areas where I felt undue pressure on.
What can be said is that the toe box volume is surprisingly generous. This was not an issue for me as I can easily fit into narrow shoes (e.g. the very old Adizero Adios 3). It is imperative you try these in store before purchasing.
The tongue is strategically padded thin, non-gusseted with a non-symmetrical v-shaped finishing (see below image) to wrap around the base of your ankle. The heel collar is also minimally but strategically padded. The mesh upper is also minimally but strategically reinforced in the heel cup and forefoot. You see what I’m trying to say? Everything is minimal, and all concessions made to provide comfort are done so intentionally and are done so for a functional purpose.
Minimal but necessary heel collar cushioning with a nicely designed anatomical asymmetrical V-shaped tongue
Minimal but necessary toe box reinforcement
Midsole & Platform
As discussed in the prior section, I would describe the overall platform to be on the narrower side where a slither of my big toe protrudes out, although I would say this did not cause any reduction in performance. Also as mentioned, try before you buy.
Not having worn Nike for a while (since the Alphafly 1 and Vaporfly Next% v1), I can’t compare how the ZoomX in the SF2 performs against other current Nike offerings, but it definitely is softer than the FFTurbo+ in the Asics Metaspeed Paris and perhaps only slightly softer than the Lightstrike Pro in the Adidas Adios Pro 4.
The softness of the ZoomX is stabilised by a full length carbon fibre FlyPlate runs close to the ground at the forefoot before rising to the middle of the midsole at the mid to rearfoot. The curved shape of the plate is apparent via the cutout in the midsole on the lateral side in the forefoot. As to whether the plate’s shape is the same in the VF4, this is unclear.
Weight saving is the name of the game for the SF2 with an aggressively tapered midfoot and an extensive cutout through the length of the midsole foam that exposes the full length FlyPlate. To add to the flexibility promoted through this cutout, I noticed that the FlyPlate flexes very easily. This also was the case in the SF1, which Ryan reviewed back in 2022. I particularly like this, as the ride is more forgiving and it feels a lot more natural to run in, like a traditional flat but with the assistance of a plate. Compare this with the Asics Metaspeed LD, which is a long distance track shoe with an integrated carbon spike plate, there is absolutely no flex offered.
Finally, and also as touched on before, the apparent zero to negative drop of the SF2 is definitely noticeable where heel striking is not an option as you would lose all efficiencies created by the rockered / curved forefoot geometry and the FlyPlate’s assistance. To do so would be to work against the shoe itself.
Outsole
Not much can be said about the outsole when there’s, well, not much of it, except that it works well when used according to its intended purpose. As in the images below, only the forefoot has extensive outsole coverage, and even then there is a sizable cutout on the lateral side where a Swoosh has been added. Note that the cutout is exposed ZoomX foam, as are the white unpainted bits between the webbed outsole design.
As in the image above, the webbed outsole pattern is textured for extra traction, with density increasing as you work your way closer to the extreme forefoot. In the image below, and akin to the SF1, two very thin rubber pieces have been placed in the rearfoot. I presume the purpose is to provide some protection for the exposed ZoomX foam. I am not so sure this works as there is considerable wear of the exposed foam where the image below was taken after one 4.5km track session where the SF2 has not seen contact with any concrete or bitumen. I am genuinely intrigued but also fearful as to how long the shoe will last if it is used for ‘road racing’.
Ride, Conclusions and Recommendations
Five smiles for what a unique, bespoke and special shoe the SF2 is and how epic it is when used for paces under 3:15/km (~5:14/mile) which is the sort of pace I can hold for 400m and 800m reps. It felt even more phenomenal at quicker paces and evidently so when I was doing 300m reps at around 2:45-55/km (~4:35/mile) where the ZoomX foam and FlyPlate really complements each other to provide for smooth toe-offs and quick transitions. However, at ‘slower’ paces below 3:30/km (~5:38/mile), the SF2 felt almost dead in the sense that it felt like a raw old school flat. I presume this is where I start to midfoot strike and fail to utilise the forefoot of the shoe, which makes up 99% of what the SF2 is all about.
Unlike its predecessor, the SF2 is not at all approachable in its geometry, stack height and drop (in today’s market and attitude towards this). While it rides fantastically at pace, it does not have the build quality for any sort of every day running, including warming up before a track session. This makes the SF2 a very specific shoe for specific uses only. For runners like myself (18 minute 5k, sub 3 marathon runner), I will only take the SF2 out for specific quality sessions, and not even for fartlek or threshold sessions. If there was a little more stack in the heel and outsole coverage, I could see myself using the shoe so much more.
My final thoughts are that the SF2 would be a competitor to the Adidas Takumi Sen 10/11, but it also is not as the TS is far more versatile. It is also like the Asics Metaspeed LD, but is technically more versatile as the SF2 can be used on the road. But the question is, would you?
I love the SF2, but I have scored it down for value as being such a unique shoe, it does not offer that much value for money due to its lack of versatility. Perhaps if I were a track athlete or a much faster runner, I could see myself scoring it a lot higher.
Score: 8.9/10
Ride 9 (50%) Fit: 10 (30%) Value: 6 (15%) Style: 10 (5%)
😊😊😊😊😊
5 Comparisons
Adidas Takumi Sen 8 (RTR Review)
On paper the TS is the shoe most similar to the SF1 and SF2, as both TS and SF are intended to be shorter distance road racing shoes. However, I think the TS is more suitable to this purpose. Whilst the TS8 is no longer as relevant, the upcoming TS11 appears to be an exciting update to the TS lineage. It appears that the TS11 would be a ‘lite’ competitor to the VF4, and the SF2 is a ‘lite’ competitor to the TS11. It seems Adidas and Nike are a little off calibration in their carbon plated line up, with the former having the TS10/11 for shorter distances, the ever versatile Adios Pro 4 for all other distances, and the illegal (stack height wise) Prime X Strung 3, and the latter having the SF2 for shorter distances, the VF4 for distances up to the marathon, and the Alphafly 3 as the flagship marathon shoe. Does the TS compare with the SF2, I’d argue no as the TS is far more versatile and able to be worn by many more more meaningfully.
Asics Metaspeed LD
At 4.2 oz / 119g in the LD, this is only one of two pairs of shoes I have worn that is lighter than the SF2. But can the LD be considered a running shoe given that it can actually only be used on track? The LD (not version 2) was released in 2023 and retailed at AUD 400 (250 USD), and was essentially the track version of the Metaspeed+, with a FFTurbo midsole and an exposed fully rigid sculpted and integrated spike plate which meant that no spikes were actually needed. The LD is intended for track races up to 10,000m. Whilst less forgiving than the SF2 in the forefoot due to the rigidity of the spike plate, it is actually more versatile as there is a perceivable drop and the shoe allows you to midfoot strike and also where the spike plate commences in the midfoot (see image below). The FFTurbo is noticeably firmer as it is nylon based and not Pebax. The SF2 is softer and is also ‘capable’ of being used off track. Similar to the SF2, the LD did not receive much, if any fanfare upon release due to is extremely limited audience.
Reebok Floatride Run Fast Pro 2 (RTR Review)
This is the only shoe I have worn that is significantly (mind boggling to use this term) lighter than the SF2, coming in at 3.88oz / 110g. It too utilises a PEBAX only midsole, but does not have a plate. The RFP2 has a lot of ground feel and has ample flex, as it has no structural aids in its construction. Whilst you can say it is a lot more versatile than the SF2, it really isn’t, as it too is calf destroying given its very minimal construction. THe RFP2 and SF2 are shoes I will only take out at quality track sessions. The difference is that with the RFP2, I can take it on the warm ups and cool downs as well. Each is unique within its own rights.
Asics Sortie Magic 6 (RTR Review)
The SM6 and SF2 also weigh the same, but the SM6 is a traditional flat with no plate, and rides even lower at close to 20mm in the heel. As a traditional flat, the SM6 has far more ground feel and requires you to generate the power with no assistance. The SM6 would also be more durable with its full outsole coverage and in particular has a better traction with a DSP waffle outsole in the forefoot. The SF2 is however the faster shoe.
Adidas Adios Pro 4 (RTR Review)
I have thrown this in as an almost tongue-in-cheek comparison. The AP4 is the total opposite of the SF2, as with other max stack plated supershoes. I compare the AP4 because it is a shoe I would be willing to wear for the marathon, but also at 800m and mile repeats at 3:30/km (~5:38/mile). In terms of versatility, the AP4 is the complete opposite of the SF2. Where I would use the SF2 is for a track race if I were to enter one, and quality repeats. But for a 5000m track race, I would actually pick the AP4 over the SF2.
Index to all RTR reviews: HERE
Tester Profiles
Bryan Lim lives in Melbourne, Australia. He picked up running in mid-2016 as a stressed-out law school student and ended up running a full marathon as his first event. Ever since, he has focussed on becoming a better runner, with PRs of 1:22 in the half-marathon and 2:59 in the marathon. Bryan also enjoys longer distances and trail events, and has run the 2024 Comrades marathon in 8:05 and a driveway ultra (52km over 838 laps) in the midst of a Covid-19 lockdown. He also enjoys running tourism, completing the Chicago Marathon, Amsterdam Marathon, Shonan Marathon and Toronto Half. Whilst enjoying running, he has taken the community aspect of things with passion. Bryan is an accredited Athletics Australia community coach and runs his own local track club, Glasshouse Run Club.
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