Review: inov-8 Trailfly Ultra G 300 Max Trail Running Shoes | Trail Hub |
Review: inov-8 Trailfly Ultra G 300 Max Trail Running Shoes

Review: inov-8 Trailfly Ultra G 300 Max Trail Running Shoes

Review: inov-8 Trailfly Ultra G 300 Max Trail Running Shoes

Written By: SportsShoes

The inov-8 TRAILFLY ULTRA G 300 MAX is a revolutionary trail shoe featuring the world’s first Graphene-enhanced foam, called G-FLY™. The foam 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.

Pioneering a new way for cushioned ultra-running shoes, the inov-8 TRAILFLY ULTRA G 300 MAX also features a unique underfoot ADAPTER-FLEX™ groove, allowing it to adapt and react to the terrain like no other. And that’s not all. GRAPHENE-GRIP™ rubber delivers the world’s toughest trail traction, while the supportive upper fit adapts to the natural changes of the foot when running big miles.

It’s time to defy the limits of your long run.

Photo of the shoes

Our Trail Running Ambassador, Ben Mounsey, has been busy putting the inov-8 TRAILFLY ULTRA G 300 MAX trail running shoes to the test. Here he provides a detailed review and explains how they fit in with the rest of the inov-8 off-road shoe range.

Price: £170

Weight: 300g (average weight across sizes)

Drop: 6mm

Lug depth: 4mm

Length: Fits slightly small

Width: 5 (widest)

Stack Height: 30mm (heel) and 24mm (forefoot)

RATINGS (out of 5) - Comfort: 4 | Cushioning: 3 | Support: 3.5 | Grip: 3 | Protection: 4

Perhaps the most eagerly anticipated inov-8 launch in history, the release of the new inov-8 TRAIL ULTRA G 300 MAX is certainly one that has captured my attention.

Following in the footsteps of the inov-8 TERRAULTRA ULTRA G 270 was always going to be an extremely difficult task, especially given their incredible success. They are, in my opinion, the best all-round trail running shoes currently on the market.

Fans of the TERRAULTRA will be pleased to know that the upper design of the TRAILFLY is almost identical in terms of fit and feel. Both shoes are rated 5 on the inov-8 fit scale (meaning they’re the widest possible fit), they have the same lacing system and gusseted tongue design and are built from the same protective and durable upper materials. They’re even the same bright green colour, which over the years has become synonymous with Graphene infused inov-8 shoes.

However, below the upper, the TRAILFLY are a completely different shoe altogether and it’s refreshing to see that inov-8 are living up to their name by being extremely innovative and very bold with this latest design.

As I picked up the shoes for the first time and turned them on their side for closer inspection, it was clear that I was holding a completely different beast to its predecessor. With a stack height that even HOKA would be proud of, from the midsole down, they look anything but inov-8.

I was told to expect something different and different they most certainly are. A world apart from a shoe like the X-TALON, for example, as rather than feeling a close connection with the ground, you’re raised far from it. I’ve previously tested a small number of high stack shoes, but, excuse the pun, the TRAILFLY are on a completely different level altogether. Wearing them is the closest thing I’ve been to altitude training for the last 12 months. Another thing I really noticed was the drop, more so than any other shoe if I’m being honest. It feels more like 10mm than 6mm, which does encourage you to lean further forward to encourage speed and propulsion, but does take a bit of getting used to. In comparison, the TERRAULTRA are zero drop shoes, so very different in this respect.

Prior to running in the TRAILFLY, I envisaged testing the most cushioned and springy trail shoe ever made, but this is simply not the case. I’m not saying that they’re not cushioned, just that the cushioning is different to how I thought it might be. Rather than feeling soft and plush, the G-FLY™ Foam is much firmer than I expected.

Photo of the shoes

inov-8 claims that scientific tests prove that the foam infused with Graphene, the world’s strongest material, delivers 25% greater energy return and is far more resistant to compressive wear, doubling the industry standard for longevity*. Because I have only tested the TRAILFLY for a few weeks, I cannot comment on their longevity and durability over time. However, having owned a number of graphene infused trail shoes, I do believe that the addition of graphene significantly prolongs their lifespan. This is something I have noticed when comparing newer versions of the TERRAULTRA and X-TALON range to their predecessors and is something I also expect to see with the TRAILFLY.

*The industry standard is generally considered to be around 500-800km

What is also pleasing to see is that the quality and durability of inov-8 uppers continues to improve with every new release. The TRAILFLY uses a double-layered toe guard for increased strength and protection, whilst the lightweight mesh maintains breathability. Every part of this shoe is built to last and so far, I have been extremely impressed with their quality and durability.

For me, the biggest advantage of this high stack and thick midsole is not the cushioning, but the increased level of protection from sharp rocks and rough underfoot terrain. As previously mentioned, it’s a shoe as far removed from the X-Talon range as possible and that’s because it has been specifically designed and developed for a completely different environment, terrain and type of running altogether. Personally, this shoe only really suits around 25% of my weekly runs, as I spend most of my time training on soft and muddy terrain. This is not a fell shoe and therefore not suitable for all of my runs. However, it is fantastic for running around my local quarry and I also find them a pleasure to wear when switching to harder asphalt or concrete surfaces and especially when travelling at speed. As a heavy-footed runner, I really strike the ground with force. The TRAILFLY help to soak up this impact and during the relatively short period in which I’ve been testing this shoe, it’s one of the most positive things that I have noticed.

Something else that has really impressed me is the new ADAPTER-FLEX™ technology, which is a unique feature of this particular shoe. This basically means that the sole is essentially broken into two sections, by a unique underfoot ADAPTER-FLEX™ groove, which constantly adapts and reacts to the ever-changing terrain. I love this concept and I think that this design really works, allowing it to become the first high-stack shoe that moves and flexes in this particular way during a run.

For me, the TRAILFLY is a good heavy-duty training shoe because it’s slightly heavier than most other off-road shoes in the inov-8 range and is built to soak up the big miles. As the name suggests, the average weight of this shoe is 300g, but this figure is obviously higher if you have larger feet. Personally, I like to race with light and fast equipment, over shorter distances than which these shoes have been designed for. Therefore, I would use the TRAILFLY as a training shoe on hard and rocky terrain. Basically, whenever I need a shoe to cope with long distance and high impact on solid ground. As is the case with all inov-8 shoes, I have found that the grip is trustworthy and reliable across all types of off-road surfaces, with the exception of thick mud and ice. That said, I would wear other, more specific shoes, to cope with these kinds of extreme conditions.

The truth is that I honestly like the TRAILFLY the more I wear them, but they did take some getting used to, mainly because they are so different to anything I’ve previously worn before. Therefore, I gradually introduced them in-between using my regular training shoes, so that I could sensibly adapt to them. This is important if you are switching between completely different types of shoes, for example, it wouldn’t be wise to just suddenly start wearing zero drop shoes for everything you do after you’ve spent years running in shoes with an 8mm drop.


  • New ADAPTER-FLEX™ technology helps you to tackle ever-changing off-road terrain.
  • This is a shoe built to last, with an extremely durable upper and Graphene infused outsole that should double the industry standard for longevity.
  • High level of underfoot protection, especially against sharp rocks.
  • A wide fit and roomy toe-box which allows all runners to wear this shoe


  • The cushioning is not as soft and spongy as first expected. Try the inov-8 TERRAULTRA G 270 as a suitable alternative.
  • This shoe is slightly heavier than other inov-8 trail running shoes.


Because of its unique design, this shoe will inevitably attract and divide opinion. However, inov-8 have now successfully launched two very different trail shoes for ultra-distance running - the TRAILFLY and the TERRAULTRA, giving runners the option of choosing a shoe which best suits their individual needs and requirements.

So, where exactly does the TRAILFLY ULTRA G MAX fit into the inov-8 range, how does it compare to other shoes in the range and is this the right shoe for you?

Let me try and explain by picking out my key recommendations for different types of terrain and purposes.

If you are someone new to trail running and who primarily runs on the road, or is looking for a shoe to switch between different types of terrain and surfaces, then I would recommend the inov-8 PARKCLAW 260, as this is the ultimate road to trail shoe and an excellent all-rounder.

If you are someone who runs on soft and muddy off-road surfaces, where grip and close connection with the ground are the two most important factors, I would recommend either the inov-8 MUDCLAW G 260 V2, or for lightweight performance, the inov-8 X-TALON G 210.

If you are looking for the perfect all-round trail shoe, with soft and plush cushioning and unrivalled levels of comfort, then look no further than the inov-8 TERRAULTRA G 270. As previously mentioned, I consider this to be the best trail running shoe currently on the market.

And finally, if you are looking for a long-ultra distance trail shoe which can adapt and react to any kind of terrain, one that is built to last and offers plenty of protection and rebound, then the new TRAILFLY ULTRA G 300 MAX is an excellent choice.

Find out more about off-road running by visiting our trail running hub and make sure you've got all the running kit you need for your next adventure.

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