Inov8 Trailfly Ultra G 300 Max trail running shoe | Tested and reviewed

A classic range rover amongst sleek sports cars, the Trailfly Ultra has unbeatable protection, but does it's weight drag it down?

from INOV8
RRP  £83.00
featured Inov8 Trailfly Ultra G 300 Max trail running shoe

by James Forrest |
Updated on

You can’t really go too far wrong with a pair of trail shoes from Inov8. The Lake District-based brand are specialists in trail running shoes, known for making technically proficient trainers with first-rate traction. The Trailfly Ultra G 300 Max has been around for a while and has racked up an impressive array of industry gongs and best in test awards.

It is a mid-weight trainer with good levels of protection and support. Underfoot cushioning is good and the graphene-infused outsole is grippy.

It lacks the underfoot pop and energetic zip faster trail runners will want, and it’s quite heavy at 335g per shoe. But for those running big mileage distances at slower paces, who need more protection and a robust build, the Trailfly Ultra G 300 Max is an excellent ultra running shoe which fits the bill.

Sqaure framed Inov8 Trailfly Ultra G 300 Max trail running shoe
Price: £83 (RRP £165)


  • Great grip
  • High protection
  • Good stability
  • Durable over long distances


  • A tad heavy and beefy


laces and tongue of the Inov8 Trailfly Ultra G 300 Max trail running shoe

The upper is made from mesh, with some TPU overlays across the sides, heel and toebox for added toughness and abrasion-resistance, where required. The all-round feel of the uppers is quite robust and tough, rather than light and agile. They take a while to break-in, but comfort levels are pretty decent once you’re used to them. Inov8 says “the supportive upper fit adapts to the natural changes of the foot when running big miles”.


Inov8 makes a massive song and dance about this shoe’s midsole, describing it as “revolutionary” and a “world’s first”. We reckon the brand’s marketing team drank too much coffee on the day they wrote that – it’s over-the-top hype. Loads of brands have impressive midsole foam and it’d be wrong to say this shoe has anything utterly innovative.

Midsole of Inov8 Trailfly Ultra G 300 Max trail running shoe

Having said that, the cushioning is good with a reasonably springy feel and a nice comfortable ride. The sharpness of any rocks and stones underfoot are certainly dulled, and the cushioning smoothes out the feel of a lumpy-bumpy trail, which is great for tired feet on big mileage runs.

Ultimately this means the Trailfly Ultra G 300 Max lacks a bit of “ground feel” and underfoot sensitivity, which some trail runners like, but others will favour being cushioned from the harshness of the trail. The “revolutionary” stuff in this shoe’s midsole is the use of a graphene-infused EVA foam, which Inov8 calls G-Fly foam. Graphene is the magic midsole ingredient. According to the brand, it is the “strongest yet thinnest material on the planet”, an almost invisible single layer of graphite that is 200 times tougher than steel but also boasts “astonishing flexibility”.

Toebox of the Inov8 Trailfly Ultra G 300 Max trail running shoe

For a few years, it has been used in the outsoles of Inov8’s grippy footwear, but in this shoe it has been infused into the midsole foam. Inov8 says this approach “delivers 25% greater energy return and retains its optimum levels of underfoot rebound and comfort for longer, so runners feel faster and fresher over greater distances”. For long runs it works very well. But with each shoe weighing 335g (UK 8.5), which is a tad heavier than ideal, you lose some of that energy and bounce the midsole is supposed to give.


Outsole grip is the main area Inov8 excels. It is well-known for its outsole units, which invariably have rugged tread patterns, cleats and lugs with excellent bite, and an all-round design that provides slip-free traction. The Inov8 Trailfly Ultra G 300 Max’s outsole features Inov8’s graphene grip, which in this case is specifically tailored towards hard-packed, rocky trails and even road running.

lugs of the Inov8 Trailfly Ultra G 300 Max trail running shoe

The rubber lugs are 4mm deep and the tread pattern is aggressive. We found the grip excellent on forestry tracks, stony paths and mountain trails during our test runs in the Lake District fells. Another interesting feature is the groove or notch in the outsole, below the arch of the foot, which Inov8 calls the Adapter-Flex. The brand says this enables the shoe to “adapt and react to the terrain like no other”. We couldn’t really judge this feature’s efficacy in isolation and, in all honesty, couldn’t really tell whether it was making any difference or not. Having said that, the shoe certainly coped positively with mixed terrain.


It’s worth noting that Inov8 recommends you go half a size up in the Trailfly Ultra G 300 Max. The fit is described as a “wider fit” for improved comfort over long distances. There is more room and volume than some tighter-fitting Inov8 models, but the toebox is certainly not as wide as other brands such as Altra.

side shot of Inov8 Trailfly Ultra G 300 Max trail running shoe

There are lots of other options in the Inov8 Trailfly range. The TrailFly G 270 V2 is a popular zero- drop option for all distances, while the TrailFly Ultra G 280 is a lighter, bouncier, more deeply- cushioned model for long-distance runs. New for 2024, Inov8 has two fresh additions, both of which feature the brand’s new foot-shape fit, new Powerflow Pro foam and improved G-Grip rubber with more stickiness.

The brand has also simplified the naming conventions of these two new shoes, simply calling them TrailFly and TrailFly Speed. The TrailFly is more cushioned with a 6mm drop for longer runs and the TrailFly Speed lighter with a 4mm drop for faster runs.


No recycled materials are used in the Trailfly Ultra G 300 Max. Inov8 says the sustainability of the Trailfly Ultra G 300 Max is enhanced mostly by its durability. The brand told us: “Sustainability is boosted by us using graphene in the rubber G-Grip outsole and G-Fly foam midsole, which improves long-term durability. Graphene imparts its strength into both rubber and the foam to make it last longer. This means you get more miles out of your shoes, increasing the lifespan.”


side shot of Inov8 Trailfly Ultra G 300 Max trail running shoe

A chunky, supportive, protective, well-cushioned trail shoe with excellent grip and a first-rate reputation – but it’s a tad pricey

How we tested

James forrest trail running

Our tester for the Inov8 Trailfly Ultra G 300 Max was James Forrest. James is one of our long-time freelance gear testers both for LFTO and our print magazine, Trail. When he's not climbing mountains or walking unspeakable distances, he's running on his local trails in the Lake District.

As well as being a prolific long-distance walker and runner, James is also one of the most high-profile outdoor writers in the UK.

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