Deeply Cushioned Trail Running Shoes Compared: inov-8 TrailFly Ultra G 300 Max, Altra Timp Ultra Mont Blanc, and Hoka Speedgoat 5

Introduction

Ultra running has grown fast, and the brands have followed. Deeply cushioned trail shoes designed specifically for long distance over mixed terrain are now a major category, and three models stand out as the most popular picks: the inov-8 TrailFly Ultra G 300 Max (referred to here simply as the TrailFly), the Altra Timp Ultra Mont Blanc, and the Hoka Speedgoat 5.

All three have been put through serious mileage on real trails, including a challenging 45-mile ultra. They are built for the same job, but they are very different in design, fit, and personality. Here is how they stack up.

Specs: Price, Weight, and Heel Drop

The TrailFly is the most expensive of the three at around £170 in the UK, with the Altra Mont Blanc close behind at £165. The Hoka Speedgoat 5 is the most affordable at £130, making it clearly the best value of the trio.

On weight, the TrailFly is the heaviest at 342g in a men’s UK 9.5, followed by the Speedgoat 5 at 312g (in a men’s UK 10) and the Mont Blanc at a genuinely impressive 292g in a UK 9.5 given how much cushioning it packs.

Heel drop splits them further: the TrailFly sits at 6mm, the Speedgoat 5 at 4mm, and the Mont Blanc is a true zero-drop shoe, meaning the same stack height under the heel and the forefoot. Heel offset is a deeply personal choice for distance running; some runners find a bit of drop takes tension off the lower leg when fatigue sets in, while others find it gets in the way.

Upper Construction and Fit

The TrailFly takes an old-school, heavily structured approach: a soft, breathable engineered mesh with plenty of structural overlays running from heel to toe box and around the lace eyelets, plus a rubberized toe bumper for trail debris. It is a durable, secure-feeling upper.

The Altra Mont Blanc sits at the opposite end of the spectrum. It uses two lighter fabrics, a plush material wrapping the toe box to the midfoot, transitioning to a stiffer, almost see-through fabric at the rear. There is no plastic heel cup, the ankle collar padding is minimal, and the overall feel is light, stripped back, and under-structured.

The Speedgoat 5 lands in between. Hoka uses a knitted mesh that is breathable, soft, and lightweight, with a good amount of recycled fabric, a few overlays at the lace eyelets, a rubber toe overlay, decent ankle padding, and a proper heel cup. The new flared heel design has proven somewhat controversial. All three shoes share a similarly thin gusseted tongue with limited padding.

On sizing, the Mont Blanc runs true to size, the Speedgoat runs a little short in length (half a size up is recommended), and the TrailFly also sizes up slightly short. On a 45-mile effort, the TrailFly felt cramped once feet swelled, costing a couple of hours, so half a size up would have been the smarter choice. For toe box volume, the Altra’s foot-shaped design is the roomiest, the inov-8 is also generous, and the Speedgoat is the narrowest of the three, though not severely so, and the softer upper gives it more give.

Midsole Performance

All three are deeply cushioned, and all three midsoles are genuinely comfortable underfoot. The G-FLY foam in the TrailFly is the firmest of the three, which helps the shoe feel connected and stable on technical terrain for a max-cushion shoe. The trade-off is weight: you notice that midsole when you are running.

The Hoka and Altra midsoles are noticeably softer, but that softness costs a little connection on technical trails. The EGO MAX midsole in the Altra strikes arguably the best balance of comfort, connection, responsiveness, and stability, and it is the strongest midsole performer of the three.

Outsole and Grip

Grip matters, especially for anyone running wet, muddy winters and dry, dusty summers. Two of the shoes use Vibram Megagrip: the Speedgoat 5 and the Mont Blanc, the latter in a lighter-based Megagrip variant that keeps the sticky properties while saving a few grams. Both feel confidence-inspiring on rocky ground, wet or dry. The Mont Blanc’s lugs are shallower than the Speedgoat’s, and while it performed better than expected in mud, a deeper lug would help. Hoka’s 5mm lug depth is judged to be just right.

The TrailFly uses inov-8’s graphene-infused rubber, their grippiest and hardest-wearing compound. With a 4mm lug depth and chunky lug shapes, it has performed well across wet and dry conditions with no complaints about grip or traction.

Overall Performance

None of the three are perfect, and the flaws tell the real story. The TrailFly has handled everything thrown at it, including that demanding 45-mile ultra, but a weight reduction of around 40g would make it far more responsive on shorter, faster runs and a much more versatile shoe. At £170 it is also expensive, though older colorways can now be found for around £135, which is closer to what it should have cost originally.

The Mont Blanc has bigger problems. The upper is under-structured, midfoot lockdown is difficult, and heel slip is nearly impossible to prevent. On steep technical descents the foot moves around inside the shoe, which is uncomfortable and unstable in a shoe designed for mountainous races like UTMB. Toe protection is also lacking; kicking a rock on a fast rocky descent would be a serious problem. It is a shame, because the EGO MAX midsole is brilliant. With the fit issues addressed, this could be a great shoe. This time around, the negatives outweigh the positives.

The Speedgoat 5 is a clear improvement over the disappointing Speedgoat 4 for this tester’s foot shape, though the Speedgoat 3 still fits best of all. Midfoot lockdown still requires pulling the laces tight, and a few more structural overlays around the midfoot would help both lockdown and long-term fit. That said, plenty of long-run miles have gone into this shoe happily, and it is the pick for an upcoming race.

Conclusion

If you want a deeply cushioned shoe to eat up miles over mixed terrain, the Altra Mont Blanc is worth skipping for now until the fit and lockdown issues are resolved, because the midsole underneath deserves a better upper. That leaves the TrailFly and the Speedgoat 5, and both are enjoyable shoes. Had the TrailFly been 30 or 40 grams lighter, it would likely have taken the top spot. As it stands, the Hoka Speedgoat 5 is the winner: improved fit, best value at £130, and the one most likely to earn long-term miles.