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Nike ACG Ultrafly Trail

Unisex Shoes - Hyper Crimson/Whit
This Item Ships For Free!
Shop All Nike

Nike ACG Ultrafly Trail

Unisex Shoes - Hyper Crimson/Whit
Available to order January 29, 2026
This item is coming soon.
Important Shipping Note: U.S. sales only.

Here at Running Warehouse, we want you to be completely satisfied with your purchase. If you are unsatisfied with your purchase for any reason, items can be returned with free return shipping within 90 days from the original invoice date.

We will match or beat any posted overall price advertised in-store or online on in stock items.

Ultimate. Racing. Performance. The Nike ACG Ultrafly Trail is a trail racing super shoe, made to own long-distance events with wild speed.

Best Use

Super Trail | Race UltraSuper Trail | Race Ultra

Surface

Smooth Trails & FireroadsSmooth Trails & Fireroads

Cushioning

Barefoot
Minimal
Low
Medium
High
Maximal

All Women's Road Shoes

  • Daily TrainersDaily Trainers

    As the broad base of the running shoe pyramid, daily trainers are the definition of a go-to running shoe. They prioritize dependable comfort, support, durability, and routine versatility. They're a staple in every runner's closet. If you're newer to running shoes, you can confidently start your journey here.

  • Performance TrainersPerformance Trainers

    Performance trainers (or "super trainers") blend elements of daily trainers and super shoes, often giving you the benefits of advanced foams and plates, but adapted for daily training. They make fast runs faster and long runs easier. Highly versatile, many are also great choices as accessible racing shoes.

  • Super ShoesSuper Shoes

    The pinnacle of the pyramid, super shoes are the fastest running shoes you can buy. They're designed to race your absolute best and are the apex of running shoe technology and innovation. Often built with carbon-fiber plates and cutting-edge superfoams for the highest energy return, they're made for ultimate racing speed.

Women's Running Shoes by Surface

  • Roads & PavementRoads & Pavement

    Road running shoes feature smooth outsoles that are designed for running on paved surfaces such as roads, sidewalks, and bike paths.

  • Smooth Trails & FireroadsSmooth Trails & Fireroads

    Designed to handle most trail runs, these shoes prioritize comfort and a smooth ride. These shoes are great for anything from smooth singletrack, park trails, and fireroads making them ideal for those who run from their doorstep on streets before hitting the trail.

  • Rocky & Technical TrailsRocky & Technical Trails

    These shoes are best used for hard, rugged trails such as shale, granite or sandstone where grip on smooth surfaces and underfoot protection are important.

  • Soft & Muddy TrailsSoft & Muddy Trails

    Designed for use in muddy, soggy conditions, these shoes feature very aggressive outsoles that dig deep into soft ground for exceptional traction.

  • Snowy & Icy TrailsSnowy & Icy Trails

    These shoes feature technical outsoles designed to grip snowy and icy trails making them ideal for winter trail running.

Cushioning Level

  • Cushioning level, or stack height, refers to how much shoe is between your foot and the ground. For this category, we reference the amount of cushioning below the forefoot as the heel height will be equal to or greater than the forefoot height.

    Learn more about stack heights and how we measure them.

  • Barefoot

    0-13mm. The Shoe generally does not have a midsole and feels like there is no cushioning. This shoe is all about feeling the ground underfoot.

  • Minimal

    14-18mm. The shoe has a thin midsole that allows for a natural running experience. Racing shoes and minimalist shoes are common here. These shoes offer a feeling of being connected to the road or trail.

  • Low

    19-23mm. The shoe has a slightly cushioned feel and may feature added cushioning technologies. Performance training shoes and some trail shoes are common here. These offer protection during footstrike but prioritize a lightweight, grounded experience.

  • Medium

    24-28mm. These shoes have a stack height that fall near the middle of the spectrum.The shoes in this category are verstaile and great for all types of runs and distances.

  • High

    29-34mm. The shoe has a thick midsole and ample cushioning. These shoes are highly protective and absorb more impact than the body.

  • Maximal

    35mm plus. The shoe has an extremely thick midsole and extra cushioning. The focus is on protection and soft foam underfoot with hardly any ground feel.

Stability Level

  • Neutral Running Shoes

    Neutral shoes support the foot through a normal range of arch collapse and generally do not have built-in technology to correct movement.

  • Stability Running Shoes

    Stability shoes are a great option for those who overpronate or need added support. These shoes help to limit the inward rolling motion of the ankle while running or walking and assist in guiding the foot straight through the gait cycle.


At A Glance:

  • Vaporfly of the trails? Check. 
  • Less weight + more energy = greater speed 
  • Re-optimized carbon fiber plate 

Product Highlights:

Yes fans, it's here! LONG desired, the Nike ACG Ultrafly Trail is a drool-worthy upgrade for a trail running super shoe that's worth the wait. It's made to dominate 100-mile ultramarathons over smooth-to-moderate terrain, with lightweight agility to shred shorter distance races too.

Starting in the midsole, its two layers of ZoomX superfoam have been unlocked for even more energy return. Nike removed the external fabric wrap found on the original version. With less weight and more freedom for the foam to work, you get greater efficiency to feel fresher for longer.

Crucially, the full-length carbon fiber Flyplate is optimized from many rounds of testing and feedback. Now 30% more flexible, the previous wishbone shape is replaced by medial and lateral plates that are fully independent. Now more adaptable to uneven terrain, you'll enjoy better control and smoother transitions.

Connecting you to the trail, the Vibram Megagrip outsole is an Ultrafly-exclusive pattern. This full-length design sheds additional weight, while the 3 mm Traction Lugs deliver sticky grip for moderate trails and exposed rock sections. Completed with a vapor mesh upper, it delivers quick-drying breathability and confident lockdown, so all you have to do is run.

Refined from top to bottom, lighter in every area, and more energetic than ever, the Nike ACG Ultrafly Trail is made for your fastest trail races ever. Lace up and go claim your crown!

Model Number: HF5668-801

Specs & Fit

Shoe Specs

  • Weight: 9.5 oz | 269 g
  • Heel Stack: 38 mm
  • Forefoot Stack: 29.5 mm
  • Heel-Toe Offset: 8.5 mm

How We Measure Our Shoe Specs

  • We measure every shoe in-house to provide accurate and consistent details.

  • Weight

    The weight is based on a Men's size 9 for Men's and Unisex shoes or Women's size 8 for Women's shoes. The weight listed is for a single shoe, including the laces.

  • Heel Stack

    The heel stack refers to how high your heel sits above the ground when wearing shoes. Based on Men's size 9 as the standard.

  • Forefoot Stack

    Forefoot stack refers to how high the ball of the foot sits above the ground when wearing shoes. Based on Men's size 9 as the standard.

  • Heel-toe Offset

    Heel-toe offset (drop) is the difference in height between the heel stack and the forefoot stack. We use the number given to us by the brand.

How We Measure Shoe Fit

  • All measurements are based on Medium width. Note: fit is relative to the "average" running shoe.

  • We partner with SmartLast, a program by Heeluxe, to use advanced shoe-measuring technology, to provide objective measurements for toe box, midfoot, and heel widths as well as overall length.

Cushioning Level

  • BarefootBarefoot

    0-13mm. The Shoe generally does not have a midsole and feels like there is no cushioning. This shoe is all about feeling the ground underfoot.

  • MinimalMinimal

    14-18mm. The shoe has a thin midsole that allows for a natural running experience. Racing shoes and minimalist shoes are common here. These shoes offer a feeling of being connected to the road or trail.

  • LowLow

    19-23mm. The shoe has a slightly cushioned feel and may feature added cushioning technologies. Performance training shoes and some trail shoes are common here. These offer protection during footstrike but prioritize a lightweight, grounded experience.

  • MediumMedium

    24-28mm. These shoes have a stack height that fall near the middle of the spectrum.The shoes in this category are verstaile and great for all types of runs and distances.

  • HighHigh

    29-34mm. The shoe has a thick midsole and ample cushioning. These shoes are highly protective and absorb more impact than the body.

  • MaximalMaximal

    35mm plus. The shoe has an extremely thick midsole and extra cushioning. The focus is on protection and soft foam underfoot with hardly any ground feel.

Technologies

MIDSOLE 

  • ZoomX superfoam creates a featherweight double layer of high-energy performance. 
  • Carbon fiber Flyplate is full-length, 30% more flexible, and split into fully independent sides for smoother control. 

OUTSOLE 

  • Vibram® Megagrip with Traction Lug technology provides industry-leading grip on wet and dry surfaces. Its Litebase bottom layer is 50% thinner and 30% lighter than standard outsoles. 

UPPER 

  • Vapor mesh is made for durability and quick-drying breathability. 
  • Midfoot band adds comfortable containment for secure foot lockdown.

Customer Reviews

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