It is here, the much anticipated Nike Ultrafly has finally hit the shelves and has caused a bit of a stir in the trail running world. Ever since Nike announced the release of this shoe almost a year ago, I have been dying to get hold of a pair, and I have been lucky enough to be given a pair from Run4It to test prior to general release to test them out and give my thoughts on them. I’ve been able to get out for several runs in the Ultraflys to see how they fit, feel and how I believe they would fit into a shoe rotation.
Nike Ultrafly features & specifications:
- Weight: 284g (US9)
- Stack height: 38.5mm heel / 30mm forefoot (8.5mm drop)
- ZoomX foam
- Carbon Flyplate
- Vibram Litebase Megagrip Outsole
- 3.5mm lugs
- Vaporweave Upper
What makes the Ultrafly different and what is it designed for?
The Ultrafly is Nike’s first true attempt at bringing their ground-breaking ‘supershoe’ technology, seen in the Vaporfly and Alphafly, into a high-performance trail shoe. Nike pitch the Ultrafly as a do it all trail racer, for all-out efforts on shorter trail runs, to days-long attempts out in the mountains, exactly what the Vaporfly is for road racing.
They are doing so because it is now evident that in road races of all distances, particularly longer ones, the features found in ‘super shoes’ can improve running economy and delay the onset of muscle damage, elevating performance.
Whilst this type of shoe has been available since 2016 for road racing, it is only recently that this tech has begun to trickledown into trail shoes, with limited success. This is because the demands on trail shoes, and what makes them comfortable and efficient are not the same as their road racing counterparts. For instance, trail shoes require better tread to give confidence on more rugged terrain, and exposing some of these newer foams to trails can cause them to wear away much faster. Furthermore, if a shoe is too stiff, it won’t flex properly when contouring hills and scaling steep inclines, making them feel uncomfortable and potentially less efficient. These are all features found in newer road racing shoes, so the real test at bringing these technologies over into trail shoes is to see whether these shoes can be agile, stable and durable enough, whilst still providing that signature bounce and equivocal performance benefits of their road counterparts.
How they fit and feel on
Out of the box, you can tell that this is a very special shoe. The build quality of the shoe is exceptional, and you get the impression Nike have paid a lot of attention into nailing its core elements, and stripping back excess to ensure the shoe is slick and nimble.
On foot, the Nike Ultrafly fits true to size. I usually take a 10UK in Nike and I have about a thumb width at the toe which is perfect for me. When slipping on, I noticed they fit a little loose around the heel. However this wasn’t noticeable when running and I didn’t need to put a lock lace in. The heel then tapers into a much more snugly fitting midfoot, which is achieved by an internal gusset and external upper overlays, and then broadens into the forefoot which lets my toes splay nicely. Whilst wider fitting, I didn’t notice my foot sliding about in them when running. This is something I really appreciate when running on cambered surfaces and when cornering.
The upper is made of a light mesh material called Vaporweave, which appears to be the material used in earlier Vaporfly Next % models or is at least very similar. It is very breathable and does a great job at keeping the foot locked down. Furthermore, the upper doesn’t hold onto water and drains well, keeping the shoe light even if your route takes you through water. The tongue is wide and gusseted, with a bit of padding to protect your foot from lace bite. This design works well at preventing trail debris entering the shoe.
How the Ultrafly cushioning feels
The midsole in the Ultrafly uses two layers of ZoomX foam with a carbon fibre flyplate sandwiched between them. The midsole has a wrap of a fabric-like material around it, to help protect the ZoomX from scuffing and breaking down when exposed to trail surfaces and to stabilise the foam itself. The midsole base is also noticeably wide, with lots of outsole in contact with the ground at any one time. In hand, you can feel the softness of the midsole through the fabric, however it is very stiff when trying to bend the shoe, which I had reservations about when taking it onto the trails.
Those reservations where quickly dispelled however when out running. The Ultrafly was pleasantly soft underfoot, particularly through the heel, and that stiffness was not noticeable at all, with the rockered forefoot providing a nice propulsive feeling at toe-off at a range of paces. Nike haven’t shared too many details about how the flyplate in the Ultrafly differs to the plate found in the Vaporfly, but it doesn’t feel as curved or aggressive, meaning the ride of these shoes at slower paces (for me 5:15min/km to 4:30/min/km) isn’t too harsh. The Ultrafly also felt very stable underfoot when running on road and light trail, which I think can be accredited to that wide base-net and the midfoot lockdown.
When picking up the pace, the shoe had something similar to the distinctive Vaporfly ‘pop’. Going up the gears to a steady pace was effortless and it was really very easy to then maintain those higher speeds. However, the shoe’s additional weight was noticeable at faster paces approaching my 5-10km race pace, which is about 3:00-3:10min/km. Moreover, when hitting more technical sections and sharp corners, I didn’t feel quite as balanced in the shoe, similar to how I feel in the Nike Alphafly on the road sometimes, and had to take a wider lines on these occasions, or slow the pace. I think the softness of the foam, and stack height are contributors to this.
Protection wise, I did not notice any rocks or routes pushing up through the shoe on any occasion, with the high stack and fly plate providing a more than ample buffer between the trail and my foot.
The Ultrafly uses Vibram Litebase Megagrip. This is the first time Nike have used Vibram in a trail shoe and demonstrates that they are eager to make sure the Ultrafly can compete with the leading contenders in the trail racing space.
The 3.5mm lugs are chevroned and evenly spaced out to ensure you get a good hold on looser terrain and debris doesn’t cake up on them when hitting softer sections on the trail. On rock this tread works perfectly, even sticking to smooth wet rock sections with ease. The tread was also very effective on slick grass and held well on steep inclines, with no back slippage when driving hard uphill.
The shallow lugs also meant that on more runnable trails and road, the shoe felt really smooth and you don’t feel the lugs pushing up into your foot at all. The caveat to that is that on muddier sections, and slicker descents, the shoes grip isn’t ideal. This is not the shoe to be lacing up for boggy hill races and or races with steep slippy descents. I noticed some sliding on this type of terrain and did not feel confident to up the pace on these sections in the Ultrafly as a result.
How can the Nike Ultrafly improve your run?
We position the Ultrafly running shoes in our Trail category. The Ultrafly feels best when you’re trying to run at a steady tempo pace and excels on rolling light trails and single track. It is an absolute rocket on this type of terrain, and I distinctly noticed less muscle soreness after longer efforts in them compared to similar trail shoes. It is also an absolute joy to run on roads on.
As such, I feel as though the Ultrafly is best placed for longer trail efforts and races, and generally for that kind of terrain I don’t think you can find anything better than the Ultrafly on the market currently. For shorter efforts of 45 minutes or under and on more technical, muddier terrain, I would still prefer something that is lighter, with a little less stack height and more lug depth than what the Ultrafly provides.
If you’re looking for a shoe that provides the same degree of protection and cushion in a less race specific set-up, underfoot feel, you should look at the Nike Zegama. Alternatively, if you may want something just as race-ready but lighter and nimbler on loose and uneven terrain, you should look at the NNormal Kjerag as a potential option.