The Nike ACG Ultrafly Trail is a buy for people chasing time or placing in trail races. About 276g in 27cm, the lightest of the 3 ACG shoes, with a ZoomX sole and a carbon plate end to end. The drop is 8.5mm. The official price is JPY 36,080, the highest of the 3.
The Shoe Nerd's top pick
This shoe's selling point is that the plate was "softened," not "stiffened." Road race shoes roll you forward with plate stiffness, but on stones and roots a stiff plate tilts the foot along with it. Nike lowered the plate's stiffness from the original and cut slits in its back so it flexes. I read it as a shoe for someone who chases time in trail races and can pay the highest price of the 3.
Key points
- The lightest of the 3 ACG shoes. 39g lighter than the Zegama in 27cm and 51g in 28cm
- The plate is less stiff than the original, with slits cut in its back. The maker explains it flexes over roots and rocks
- 97g heavier than the road Vaporfly 4 in 28cm. Not a shoe to expect a road race shoe's lightness from
Official numbers: the ACG Ultrafly Trail is about 276g with a plate
The stiffer the carbon plate, the better. That is a view that spread with road thick-soled shoes. But this shoe's product page says it "reduced" the plate's stiffness from the original.
I write the reason in a later section. First, the numbers. They are what I read on Oct 13, 2026, from Nike Japan's official product page, and the release timing is taken from Nike's own announcement of Aug 24, 2025.
| Item | Official specs |
|---|---|
| Release (worldwide announcement) | Spring 2026 |
| Official price (Japan, incl. tax) | JPY 36,080 |
| Weight (one shoe) | About 276g (27cm) / about 287g (men's 28cm) |
| Drop (the official term is offset) | 8.5mm |
| Last | Trail-specific with a widened forefoot and heel (announcement) |
| Plate | Yes (an end-to-end carbon plate; Nike's name is Flyplate) |
| Midsole foam | ZoomX (the insole is ZoomX too, per the announcement) |
| Outsole rubber | Vibram Megagrip (the announcement writes Vibram Litebase) |
| Sizes | 24 to 31cm (0.5cm steps, 15 sizes) |
| Colors | 6 colors |
| Terrain label | For low to high difficulty courses |
Going from 27cm to 28cm adds 11g (287 − 276). That is about 4.0% (11 ÷ 276). It is smaller than the Zegama's 23g and the Pegasus Trail's 19g, a build that does not get heavy easily even in larger sizes.
Image: Rakuten Ichiba
Nike ACG Ultrafly Trail
Lowest price on Rakuten is JPY 36,080 (as of 10/13), ranging up to JPY 101,800 depending on the shop. Prices change daily.
RecommendedSee it on Super Sports XEBIOSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanCompared with the original: a slit cut into the back of the plate
The changes the announcement lists are 4 places: plate, sole, upper and last.
| Place | Official description |
|---|---|
| Carbon plate | A rebuilt Flyplate. Stiffness lowered from the original, with slits cut in the back so it flexes over roots and rocks |
| Midsole foam | ZoomX in a form visible from outside. It deforms to the shape of the ground. The heel side is not wrapped |
| Upper fabric | A rebuilt mesh. Water drains easily and air passes easily |
| Last (shoe form) | A trail-specific last. Widened at the forefoot and heel, with room around the toes |
| Parts that hold the foot | An inner band, and a tongue attached to the upper fabric |
What I want readers to know is the mechanism in the 1st row. The plate is a part that gathers into 1 sheet the motion of the sole foam compressing and returning. On a flat paved road, the stiffer the plate, the more the direction of force lines up.
A trail's ground is not flat. If you step on the corner of a stone with a stiff single plate, the plate does not bend and tilts the whole shoe sideways. So Nike lowered the plate's stiffness and cut slits in the back. The explanation is that since the left and right of the plate can move separately, the plate can absorb bumps in the ground.
The product page says the same thing briefly: stiffness reduced from the original, control on trails raised. Though it is about a plate, the word is "control," not "rebound." Here the difference in thinking from road race shoes shows.
What can be said in numbers is the amount put into making it. According to the announcement, development took over 2 years, with test wear in 13 stages, over 30,000 miles in all. The testers were runners from 7 countries and 25 US states.
- 30,000 miles = about 48,270km (30,000 × 1.609)
- Per stage, about 3,713km (48,270 ÷ 13)
- As full marathons, about 1,144 races' worth (48,270 ÷ 42.195)
The announcement says it is the greatest distance in recent years for the test wear of a single Nike product. Athlete Caleb Olson won the Western States in a prototype-stage shoe.
Zegama and Pegasus Trail compared: a 39g and JPY 9,020 gap from the siblings
| Ultrafly Trail | Zegama Trail | Pegasus Trail | |
|---|---|---|---|
| Official terrain label | Low to high | High | Moderate |
| Plate | Carbon plate end to end | Rock plate in the forefoot | None |
| Drop | 8.5mm | 4mm | 8mm |
| Weight (27cm) | About 276g | About 315g | About 286g |
| Weight (28cm) | About 287g | About 338g | About 305g |
| Official price | JPY 36,080 | JPY 27,060 | JPY 17,930 |
| Price gap from the Ultrafly | — | −JPY 9,020 | −JPY 18,150 |
| Price per 1g saved | — | About JPY 231 | About JPY 1,815 |
The gap from the Zegama is 39g in 27cm (315 − 276). In 28cm it widens to 51g (338 − 287). The sole foam is the same ZoomX, so what makes the gap is the Zegama's 2nd layer of foam, the ankle fabric, and the amount of rubber.
The gap from the Pegasus Trail is only 10g (286 − 276). For that, the price is 2.01 times (36,080 ÷ 17,930). On lightness alone it does not pay. What you pay for is 3 things: ZoomX, the carbon plate and Vibram rubber.
The drop differs from the Pegasus Trail by only 0.5mm (8.5 − 8). Wearing the Pegasus Trail on everyday mountains and the Ultrafly on race day is a pairing with no strain in terms of heel height. It differs from the Zegama by 4.5mm.
- Chasing time or placing in a race, a course with long runnable sections → Ultrafly Trail
- The goal is to finish, and you want to protect your feet on rocks and long descents → Zegama Trail. The plate is there to protect, not to roll
- Want 1 pair to cover training and the paved roads to and from → Pegasus Trail
- I do not recommend buying it as a first trail shoe. For half the price, there is the Pegasus Trail with the same 8mm-class drop
What I like
It brings road race materials straight to the mountains. ZoomX is the foam Nike writes as the lightest, softest and best returning, and the announcement gives its return as 85%. Plus a carbon plate. The combination is the same line as the Vaporfly.
On top of that, the tweaks for the mountains are detailed. A soft plate, a last wide at the forefoot and heel, an upper of cloth that drains water. The announcement even includes wading through water in its assumptions.
The range of destinations is the widest of the 3 too. The Japan official terrain label is "low to high difficulty." The announcement writes it is a shoe for every trail event, from events climbing 1km of elevation straight up to multi-day stage races.
The size range is wide too. 15 sizes from 24cm to 31cm, 2 more than the other 2. The announcement says it comes out in both men's and women's sizes.
Things to watch
If you read the numbers thinking "it's a race shoe, so it's light," you miss. The Vaporfly 4 I read in this site's article on Nike's 10 running shoes is about 190g in 28cm. The Ultrafly is about 287g in the same 28cm, so 97g heavier (287 − 190).
Even against the road daily Pegasus 42 (about 300g in 28cm), it is only 13g lighter (300 − 287). The Vibram rubber and the widened sole add to it. It is light only within the 3 trail shoes.
The price is the highest of the 3 and about JPY 131 per gram (36,080 ÷ 276). It exceeds 2 times the Pegasus Trail's about JPY 63.
The sole rubber's name is split: the product page writes "Megagrip" and the announcement "Litebase."
Who the Ultrafly Trail fits
- Good fit: someone chasing time or placing in trail races
- Good fit: someone entering courses with a high share of forest roads and runnable mountain paths. The plate and ZoomX work for a long time
- Good fit: someone who normally wears the Pegasus Trail and wants a different shoe only on race day. The drop gap is 0.5mm
If the goal is to finish, the Zegama, JPY 9,020 cheaper with more protective parts, fits better. It is the highest of the 3, so leaving training to the other 1 makes it last longer.
Price and where to buy
| Model | Official price | Rakuten price |
|---|---|---|
| ACG Ultrafly Trail | JPY 36,080 | JPY 36,080–101,800 |
| Ultrafly (original) | Not listed on the Japan official site | JPY 23,700 |
| ACG Zegama Trail | JPY 27,060 | — |
| ACG Pegasus Trail | JPY 17,930 | JPY 17,800–83,500 |
When searching in a store, look at "ACG" at the start of the name. The "Ultrafly" without ACG is the original, the generation with the stiffer plate. It also has the last from before widening the forefoot and heel.
Even if the original remains cheaply, for this shoe I would choose the current generation. What changed is not the color or the fabric but the plate itself. The reason for using a plate on trails has been rewritten between generations.
Image: Rakuten Ichiba
Nike ACG Ultrafly Trail
Lowest price on Rakuten is JPY 36,080 (as of 10/13), ranging up to JPY 101,800 depending on the shop. Prices change daily.
RecommendedSee it on Super Sports XEBIOSee it on Rakuten IchibaSee it on Yahoo! Shopping Japan
Image: Rakuten Ichiba
Nike Ultrafly (original)
Lowest price on Rakuten is JPY 23,700 (as of 10/13). Prices change daily. Shoes are best tried on in the evening, when your feet swell, with your usual socks. Fit varies by brand, so check the return and exchange terms on the shop page before you buy.
RecommendedSee it on Rakuten IchibaFAQ
How do the ACG Ultrafly Trail and Zegama Trail differ?
Ultrafly if you aim for speed, Zegama if you want to protect your foot on rocks. The Ultrafly is 39g lighter in 27cm and JPY 9,020 more. The plates differ in role too: an end-to-end carbon plate versus a rock plate in the forefoot.
How does the ACG Ultrafly Trail fit?
It is built with room at the front and heel of the foot. The announcement says the trail-specific last widens the forefoot and heel. Holding the foot are the inner band and a tongue attached to the fabric.
Japan official sizes are 15, from 24 to 31cm in 0.5cm steps. The page I opened was a single row starting at 24cm.
Can the ACG Ultrafly Trail be used for training?
You can, but I do not recommend it on price. It is a shoe for "trail running and racing."
Whether to wear down a shoe at about JPY 131 per gram on everyday mountain runs. Using the ACG Pegasus Trail, with nearly the same drop, as your everyday shoe and saving this one for races is the straightforward setup on the numbers.
Up to how many km of races can the ACG Ultrafly Trail be used?
The announcement lists everything from short climbing events to multi-day stage races.
In long races, the mandatory gear list is set before the shoes. I lined up the items in the article on mandatory gear for 4 trail races. If you want protection in a long race with lots of rocky ground, comparing with the ACG Zegama Trail article makes the difference clear.
