inov-8 TrailFly Ultra G 300 Max trail running shoes review: a perfect combination of durability, grip and performance

The inov-8 TrailFly Ultra G 300 Max is a long-lasting, hard-wearing trail shoe offering high comfort and performance levels, and excellent grip on rocky terrain

inov-8 TrailFly
(Image: © inov-8)

Advnture Verdict

Excellent trail running shoes for mid- to long-distance runs on rough and rocky terrain in any conditions, perfectly combining durability, grip and performance.


  • +

    Very durable outsole

  • +

    Excellent grip

  • +



  • -

    Very little trail feel

  • -


You can trust Advnture Our expert reviewers spend days testing and comparing gear so you know how it will perform out in the real world. Find out more about how we test and compare products.

First impressions

When inov-8 unveiled the TrailFly Ultra G 300 Max in April 2021, there was a flurry of excitement about the well-orchestrated launch in the muddier media outlets and among the ranks of trail running shoe fetishists. 

The British brand has been pioneering exciting and tough new shoes for years now, and the TrailFly Ultra G 300 Max featured the world’s first graphene-enhanced midsole compound (called G-fly foam). Combined with the extreme durability of the graphene-enhanced rubber outsole the brand introduced in 2018, this shoe, we were told, was about to take trail running footwear into a whole new realm.

As has been written about exhaustively before, Graphene has been reported as the world’s strongest material, but as a nanotechnology it is also one of the thinnest. When inov-8 included the two-dimensional honeycomb lattice carbon allotrope (say that 10 times fast while running over rocks!) into a proprietary foam compound with help of scientists at the University of Manchester, it resulted in 25 percent more energy return and vastly enhance durability compared to other midsole. 

The tech is impressive, there’s no doubt about that, and the brand have been putting their products on the hooves of ultra athletes such as Paul Tierney and Damian Hall, who have worn them while achieving astonishing things in the adventure-sphere. 

We got our hands on a few pairs of TrailFly Ultra G 300 Maxs early on, and a lot of the hype seemed justified. It was a late entry, but the shoe was so impressive that our trail testers (male and female) in both the United States and the UK quickly nominated it as the stand-out winner of the Best Trail Running shoe gong in Advnture’s 2021 Awards. 


• RRP: $190 (US) / £170 (UK)
• Weight (per shoe): 300g / 10.6oz
• Drop: 6mm
• Materials: Synthetic upper; G-fly mid sole; Graphene outsole
• Colors: Green and black
• Compatibility: Ultra running, all-distance trail running on hard and rocky terrain, and some road running

inov-8 Trail Fly

(Image credit: inov-8)

On the trails

Now, two months since the much-hyped launch, we’ve had a chance to wear the TrailFly Ultra G 300 Max for a lot more time on the trails, putting in hundreds of kilometers on the rough stuff. And the short verdict is, our decision to award the shoes the top spot in the hotly contested Best Trail Running still stacks up. Although, of course, they are not 100% perfect – running preferences are very subjective, so universal perfection does no exist.


As trail runners, we want long-haul comfort from soft cushioning, rugged durability, grippy traction and energy propulsion that puts a spring in our steps, and the inov-8 TrailFly Ultra G 300 Max offers all of that and more. 

Also, it doesn’t have the unyieldingly firm sensation many new trail shoes do, with carbon-fiber propulsion plates embedded in their midsoles – instead, with these there’s a soft, flexible and resilient sensation that will pay dividends deep into a long training run or a 50k or 100-mile trail running race. 


The Ultra in the name isn’t there for fun – these are designed for longer runs and trail escapades. They are perfectly good for short runs too, but the full benefit of the tech in the midsole and the level of support in the chassis will be appreciated more the further you run in them. The synthetic uppers are not waterproof (and neither would most runners want them to be), but the TrailFly Ultra G 300 Max drains and dries out quickly after water crossings, without taking on much weight.

On the downside, if you’re a tactile runner and you like a bit of trail feel, you’re not going to get any of that with these shoes, which have a chunky, almost maximist midsole with a rocker, which performs well in terms of transference of energy, but completely cuts out any feedback from the terrain below your feet. Again – if you are sticking in some serious mileage, this is likely less of a beef (and more of a benefit) than if you are pootling around your local trails 5k at a time.


The killer combination of durability and grip is always the main focus with inov-8’s graphene-based trail shoes, and the TrailFly Ultra G 300 Max continue to deliver on this front, to the surprise of absolutely no one. There has been some criticism of the brand in the past, because the shoe uppers degrade quicker than the outsoles (for the fairly obvious reason that they’re not made from the toughest material on the planet).

In my personal experience, the uppers of inov-8 shoes I have run thousands of kilometers in have held up remarkably well, and so far (closing in on 250km run on mixed terrain in the TrailFly Ultra G 300 Max) I can see no signs of the chassis degrading or any other wear and tear (not that I’d expect it). These shoes are my go-to trail runners at the moment, and I will update this review after another few hundred kilometers to further report on the durability of the uppers.

Pat Kinsella

Author of Caving, Canyoning, Coasteering…, a recently released book about all kinds of outdoor adventures around Britain, Pat has spent 20 years pursuing stories involving boots, bikes, boats, beers and bruises. En route he’s canoed Canada’s Yukon River, climbed Mont Blanc and Kilimanjaro, skied and mountain biked through the Norwegian Alps, run an ultra across the roof of Mauritius, and set short-lived records for trail-running Australia’s highest peaks and New Zealand’s Great Walks. He’s authored walking guides to Devon and Dorset, and once wrote a whole book about Toilets for Lonely Planet. Follow Pat’s escapades on Strava here and Instagram here.