Inov-8 TRAILFLY ULTRA G 300 MAX Review

Inov-8 is a brand that has spent years developing shoes that stimulate your feet to function and have a feel for the technical ground beneath you. Inov-8 road running shoes are firmer and more responsive rather than soft and pillow-like like many, which is the current market trend. For Inov-8 to make a shoe with a midsole stack height in the heel of 25mm is a real step away from what they have previously developed. The midsole stack height of the Roadclaw 275 for example is 20mm at the heel. This change reflects the current trends in running and when Inov-8 started selling shoes to fell runners in 2003 there wasn’t the number of trail races around that there are now. Off-road races were cross countries or fell races on very soft ground. Now runners are inspired to do a trail ultramarathon as their first race and they want shoes that will help them achieve their goals. As a result Inov-8 have evolved and developed a shoe that will cope with the variety of terrain and offer the runner the protection required to help them stay the course through higher mileage.

The terrain of trail ultramarathons varies, as it does a lot up and down the UK so the level of grip offered in shoes designed for these events also varies. The one thing that all shoes designed for off-road ultras do have is resilient cushioning. It can’t just be initially soft. It must offer some bounce and give the shoe some structure after 20 hours or so of constant use on firm tracks. The basic midsole of a trainer is made of EVA. This is rubber with lots of little bubbles in it. When you run you compress these bubbles and they spring back. When you have been running a long time they don’t all spring back and the midsole starts to feel a bit flat. If you stop running and put the shoes away for a day or so before your next run then the midsole recovers. It will breakdown over time and some of the bubbles will break. As a result, the shoe will lose its structure and cushioning over hundreds of running miles done in shorter (in terms of Ultra’s) runs. In ultra-distance races you don’t have the option to stop and let your cushioning spring back. This EVA type of midsole would start to feel flat just as your legs are starting to get tired. The midsole of shoes designed for Ultra’s have been developed to still absorb shock and hold structure after long continuous use.

To get this level of resilience in their midsoles Inov-8 has added Graphene. This makes the midsole still able to give some rebound and hold its structure after prolonged use. Like towards the end of a 100 mile race. The density of midsoles with this level of resilience tends to be firm and so Inov-8 have added their Boomerang insole. This gives the shoe a soft initial feel and has a high rebound.

The heel to forefoot drop is 6mm so the ‘TRAILFLY ULTRA G 300 MAX’ can be used by a heel or midfoot striker with equal comfort.

Although Inov-8 rates the width of the G 300 Max ‘5 out of 5’ on their fit scale i.e. the widest, I found them narrower than the Terraultra G270, with a lot less height in the toe box. I also found them a little shorter too. To get the same fit as I have in my Terraultra G270’s I have to go up half a size. Some of this fit is due to the difference between the fit of a zero drop shoe that requires room for your foot to spread on impact and function in the shoes and a shoe designed to also cope with the breaking forces associated with a heel strike. It’s no surprise that the fit in the midfoot was also snugger in the Trailfly Ultra.

For a shoe with this stack height you don’t feel it. The firmness of the cushioning stops you from feeling like you are ‘sinking’ into the shoe with every step and losing energy. The outsole is also splayed out to make the shoe wider at the base. This gives a very stable feel to the shoes.

Generally speaking the thicker the midsole the less flexible the shoe. Shoes that are softly cushioned feel more flexible than they are, as you flex into the cushioning rather than bend the shoe. A lot of these shoes have a rocker as well so the shoe rolls forward. The Trailfly Ultra isn’t soft and squishy. To make the shoe flex Inov-8 have put in a flex point called the ‘adaptor-flex’ just as the heel finishes. This in addition to the flex in the forefoot makes the shoe feel less ‘clumpy’ and less like a shoe of this stack height.

The lugs on the outsole are 4mm in length and well spread out to reduce clogging in the mud. The sole is made from a sticky rubber infused with Graphene to make it more durable than the soft sticky rubber would be on its own.

The shoe has a reassuringly solid feel and is specifically designed for ultramarathon distance, so the shoe has a comfortable ‘keep you going’ sort of a feel! This doesn’t mean that I am running any slower in the TrailFly, I just feel confident that I can keep going for a long time.

The TrailFly is designed for a variety of trail terrain. I have run on everything from open moorland, farmers’ fields, tarmac roads to hard-packed bridleways. Like all more cushioned shoes of this type it is happier on the harder packed terrain. However, it is versatile enough to cope well with a variety of terrain including my single-track paths through the heather. The flex in the shoes makes them a lot better than other shoes with this level of cushion and stack height.

As with all shoes of this type, these are best used for remaining comfortable during longer runs.

Charlie @ Northern Runner Newcastle

Other Considerations
Hoka Mafate: Hoka where the first brand to produce shoes with such a high stack height. The Mafate is Hoka’s ultra shoe designed for a variety of trail surfaces. They are stiffer than the Trailfly and so not as good on the single track rough terrain. Here is our review:
https://www.northernrunner.com/blog/hoka-one-one-evo-mafate-2-review

Scott Supertrac Ultra RC: These aren’t as cushioned but, rely on the rocker to make you light on your feet. The grip is very good on wet ground but, versatile enough for hard packed too:
https://www.northernrunner.com/search/supertrac-ultra

Scott Kinabalu Ultra RC: Similar to the Supertrac Ultra RC these too rely on the rocker. The stud length isn’t as long as on the Supertrac which makes them smoother on the firmer terrain:
https://www.northernrunner.com/search/kinabalu-ultra-rc

VJ Ultra: A similar firm stable ride:
https://www.northernrunner.com/shoes-c133/trail-running-shoes-c137/ultra-unisex-cushioned-trail-obstacle-course-racing-running-shoes-green-yellow-p6460

La Sportiva Jackal: These are the shoes that John Kelly wore for both of his Pennine Way Records. They have a firm feel to the cushioning. Here are our reviews:
https://www.northernrunner.com/blog/?s=Jackal

Topo Ultraventure: Not quite as solid feeling as the Trailfly. A broad rounded toe box allows your feet to spread and function in the shoes. Versatile enough to be used as an everyday trail shoe. Here is our review:
https://www.northernrunner.com/blog/?s=ultraventure

Altra Olympus 4: Like the Topo’s they have a broad rounded toe box that allows your feet to spread and function in the shoes:
https://www.northernrunner.com/search/olympus-4

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