Nike ACG Ultra Fly Trail Review: Road Shoe DNA for Long Trail Days

Introduction

The Nike ACG Ultra Fly Trail is an interesting proposition: a trail shoe that looks and behaves remarkably like a road shoe. During a first run of around five to six miles along the North Devon coast on the Southwest Coast Path, mixing steep climbs, narrow sections, loose rocks and tree roots, it delivered a cushioned, energetic ride that felt closer to road running than most trail shoes manage.

It is not a shoe for feeling every stone underfoot, but for long days out on runnable terrain it shows a lot of promise.

Who This Product Is For

This is a shoe for runners tackling longer trail days and ultras on runnable or moderately technical terrain, particularly anyone who prioritises cushioning and energy return over raw ground feel. If you like the sensation of a big, soft, bouncy midsole and want something that transitions easily between trail and road, it fits that brief well.

Main Strengths

The numbers are substantial: 37mm of heel stack, 28.5mm in the forefoot, an 8.5mm drop, and a weight of 10.1 oz (285g) in a UK 8.5 / US 9.5 test shoe. The midsole uses a sizable stack of ZoomX foam, which Nike claims provides 85% energy return. On the run, that translated into a very springy, energetic feel with plenty of roll through each stride.

A full-length carbon fiber fly plate sits in the midsole. It is less stiff than the original Ultra Fly and is split for added flexibility, which helps with control on lumpier, bumpier trail sections. The shoe also handled lumps and bumps well, and the relatively wide platform offered decent stability on a hard-running coastal route with no rolls or loss of footing.

The upper details are well thought out. Mesh uppers are designed to drain water away, there are well-padded heel collars with a structured heel counter, moderately padded winged tongues descending into a full gusseted internal forefoot bootie to keep debris out, and a Vibram Light Base outsole with 3mm lugs.

Fit was another highlight. In a regular size, the toe box offered enough clearance, a roomy forefoot, no pinching across the toe knuckles, and good midfoot lockdown from the thin wrapping tongue. Comfort walking on steep hills was equally good, which matters for anyone taking this shoe into ultra territory.

Things to Consider Before Buying

The biggest trade-off is grip and control. The Vibram Light Base outsole with 3mm lugs is quite shallow for a shoe aimed at challenging trail conditions, and the dry conditions limited grip testing to loose rock and surface water on misty sections.

The soft, springy midsole also takes away some stability on more technical ground. Less confident trail runners may struggle to control the shoe, and the landing lacks the reassurance of a firmer platform. Runners who want a lot of ground feel will be disappointed too: this shoe does not offer a full connection to the trail underfoot.

On price, it sits at the premium end: $260 or £229 in the UK.

Buying Advice

If your routes are mostly runnable, classic long-distance trail terrain with steep ups and downs rather than gnarly technical scrambles, the Nike ACG Ultra Fly Trail makes a strong case. It feels lightweight for a trail shoe, protective and cushioned underfoot, and comfortable enough for hours on your feet.

On the strength of a first run, it inspires confidence for a long day on this kind of terrain. But if your trails are wet, rocky and technical, the shallow lugs and soft ride are worth weighing carefully before committing.

Conclusion

The Nike ACG Ultra Fly Trail brings road shoe DNA to the trail: big ZoomX cushioning, a forgiving split carbon plate, and a comfortable, roomy fit built for long hauls. Its shallow lugs and softer landing make it a specialist for runnable terrain rather than an all-conditions trail weapon. For the right runner and the right terrain, that trade looks well worth making.