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Inov-8 Trailfly Ultra G 300 Max Performance Review

Inov-8 Trailfly Ultra G 300 Max

The Inov-8 Trailfly Ultra G 300 Max is an ultramarathon and long distance trail running shoe that utilizes a new Graphene-enhanced foam called G-FLY. 

Inov-8 has utilized Graphene-enhanced rubber on its shoes since 2018. Recently, I tested the Inov-8 Terraultra G270 and the traction was amazing. Because of that testing experience, I’m a believer in Graphene. Graphene was only first isolated in 2004. Inov-8 got interested in 2016 due to Graphene’s ability to increase the strength, elasticity, and durability of other compounds. 

For me, the question is, will Graphene help foam as much as it does rubber? Keep reading for my full performance review of the Trailfly Ultra G 300 Max.

The Trailfly Ultra G 300 Max made our Best Trail Running Shoes for Hiking list.

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Inov-8 Trailfly Ultra G 300 Max Cushion


In my first impressions post, I said the Trailfly Ultra G 300 Max may be the best cushioned trail runner on the market. There’s no maybe anymore. It’s the best cushioned trail runner on the market. Graphene’s inclusion in the G-Fly foam compound creates something slightly bouncy but still stable enough for trail use. That’s not easy to do. I understand why Inov-8 and others revere Graphene as space-age wonder material.

Graphene does have an intense smell right out of the box but it’s worth it. A few runs minimize the powerful tire rubber-esque smell and then you can focus on the positives. Graphene saves your joints while still allowing you to feel the trail. If you run a lot of trails, you’ll want this shoe in your rotation for the cushion alone.

Inov-8 Trailfly Ultra G 300 Max Traction


Graphene Grip rubber is a beautiful thing. I said in the G270 review that it made me feel like Spiderman. That feeling’s still present.

And the incredible durability is back as well. It hardly looks like I’ve put any miles on these despite running a bunch miles including some on pavement. Even the texture on the lugs is hanging around except where I toe off. I test a lot of shoes and that just doesn’t happen. It’s the kind of traction that puts your mind at ease on even the slickest of trails.

Inov-8 Trailfly Ultra G 300 Max Support


The fuse does the majority of the work keeping your foot on the footbed. You don’t really sit below the rim of the midsole foam like in a lot of shoes. And there’s not really a heel counter in the back. But the lacing structure works well to lock you down.

The 6mm drop makes it easy to stay upright. With a stack height of 24mm in the forefoot and 30mm in the heel, I was worried the height would be iffy if I hit a root the wrong way. But on my trail runs, I didn’t notice any instability when tackling root-filled sections. The combo of the upper, lacing system, and extremely grippy traction kept me upright.

Inov-8 Trailfly Ultra G 300 Max Fit


In my first run, the Trailfly Ultra G 300 Max felt a little short lengthwise but that went away on the second run. I’d recommend going true to size. Wide footers will have plenty of room due to Inov-8’s generous last and toe box. The shoe clamps down well on more narrow feet as well. The extra room doesn’t compromise stability, comfort, or fit.

Inov-8 Trailfly Ultra G 300 Max Materials


I’d still like Inov-8 to figure out a way to get the same amount of stability with less fuse. And while the G 300 Max has less fuse than the G270, it’s still a little too plasticky for $190. To some, this won’t matter, but people do ultramarathons in these bad boys. Fuse just isn’t the best material when you spend that much time on your feet. I understand they use it for durablity but hopefully once G-Fly foam decreases in price we can get a supportive but more comfortable upper construction.



The Inov-8 Trailfly Ultra G 300 Max is the first shoe to feature the Graphene enhanced G-Fly foam and it’s one of, if not the, best trail shoe on the market. The combo of amazing cushion and superior traction just puts these above the crowd.

Is $190 a high price? Sure, but that happens when you’re an early adopter of new tech. Could Inov-8 innovate a bit more with the upper? Yep. But that’s minor quibble. This shoe gets the biggest, most important stuff right and will make a lot of trail runners very happy. In fact these made our best running shoes list currently available.

How to Buy the Inov-8 Trailfly Ultra G 300 Max

The Trailfly Ultra G 300 Max is now available at Inov-8.

  • Price: $190
  • Release Date: April 8, 2021
  • Weight: 10.5oz / 300g
  • Drop: 6mm (30mm/24mm)
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Tech Specs

The Trailfly Ultra G 300 Max is Inov-8’s most advanced shoe to-date and it’s got plenty of features that will appeal to trail runners and shoe nerds alike:

  • G-FLY foam provides 25% more energy return than EVA
  • G-FLY foam doubles durability (lifespan of 1,200km / 745 miles)
  • Midsole stack height of 30mm in the heel and 24mm in the forefoot
  • Graphene Grip outsole rubber
  • 4mm deep multi-directional outsole lugs
  • Vertical outsole grooves for metatarsal independence
  • 10mm deep midfoot ADAPTER-FLEX groove for forefoot/heel mobility
  • 6mm eTPU Boomerang insole
  • Gusseted tongue
  • Wide toe-box
First Impressions

First Impressions

I received the Trailfly Ultra G 300 Max yesterday. The following quick thoughts are based on a mile walk last night and a five mile road run this morning.


G-FLY is plush with a nice little bounce. Not a huge bounce, but it’s definitely the best cushion yet from Inov-8. It feels like a more stable version of Nike React. It’s similar in feel to the DNA Loft in the Brooks Glycerin 19. It also feels softer than one of my favorite higher stack trail running shoes, the Brooks Catamount, and may now be the best cushioned trail runner on the market.


As I mentioned in my Terraultra G270 review, Graphene Grip rubber is fantastic. It feels just as grippy in the Trailfly Ultra G 300 Max. I’m looking forward to taking it out on the trails to continue testing the incredible grip strength.


There’s no heel counter but the midsole does rise slightly at the heel for an extra touch of stability. I was honestly surprised that the soft G-FLY foam was so stable. The real test will be running technical trails…but so far I’m optimistic that Inov-8 delivered a softer ride without sacrificing support.


The upper is very similar to the Terraultra G270 but uses less fuse. This is a slight improvement that I lobbied for in my review and feels good so far.


The Trailfly Ultra G 300 Max offers plenty of space for wide footers just like other Inov-8 models. However, on my initial run I thought they may run a touch short. My right foot didn’t feel like I had my typical thumbnail worth of room at the toe. I’ll monitor the sizing and make a final recommendation after some more miles in them.


My early impression is that Inov-8 produced a softer trail shoe that will appeal to a wide range of trail going runners and hikers. Not everyone can handle Inov-8’s typical 0mm drop so adding plush cushioning and increasing to a 6mm drop should win them a lot of customers.

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