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Inov-8 Trailfly Ultra G280: New Midsole!
By Chief Editor Matthew Klein

Newer technologies in road shoes often take some time to reach the trail scene. It is not until recently that we have begun to see newer foams begin to make an appearance on the dirt. Inov-8 is known for having unique footwear, particularly in the areas of fit and function. Many of their shoes are light, anatomically inspired and have interesting special purposes. The Trailfly Ultra G 280 is another one of those series. Featuring a wider anatomic toe box (rare for a shoe with an 8mm drop or greater) and a new midsole foam (FLYSPEED), Inov-8 is hoping to break into the market with the lure of an incredible new material to rival the super foams seen in road racing shoes. How the FLYSPEED foam actually performs is a slightly different story. 

Inov-8 Trailfly Ultra 6 280
Price: $185 at Inov-8
Weight: 9.8 oz, 280 g (men's size 9), Women's Weights Not Provided
Stack Height: 33 mm / 25 mm
Drop: 8 mm
Classification: Long Distance / Uptempo Trail Shoe


The Inov-8 Trailfly Ultra G 280 is a lighter-weight trail shoe with excellent grip and a slightly bouncy midsole for a variety of terrain and speeds on softer surfaces. A knit upper secures the foot well with an anatomic toebox and a low sitting upper. The new nitrogen-infused FLYSPEED midsole provides more cushioning and mildly more bounce than traditional EVA trail shoe midsoles. The Ultra G 280 is best for those that want a lighter shoe with an anatomic but secure fit that can handle easier to technical terrain at long run pace to uptempo speeds.

SIMILAR SHOES: Brooks Catamont, Hoka Torrent 2


The Inov-8 Trailfly Ultra G 280 fits me true to size if slightly short in my normal men's US size 10. The width is wider in the toebox and normal in the midfoot and heel. The volume is fairly normal except for the midfoot where it feels like it sits slightly low. This is partially due to the thinner laces that feel like they create extra pressure on the top of my foot with longer efforts. Using a Lydiard lacing pattern completely relieved this pressure and I would encourage others with sensitivities of their extensor tendons or structures on the top of the foot to consider using this technique. The toe box is anatomic and fits wider. There is plenty of room for toe splay without being sloppy. There is a decent toe guard that I have felt rubbing up against my toes. I have not had blisters, but this contributes to the slightly short feeling. I would still go true to size for the majority of distances, but those between sizes or doing ultra-distance events may want to consider a half-size up. The midfoot is normal in width, featuring a non-gusseted tongue that is secured by the laces. The tongue is slightly thinner and again I felt the laces bite into the top of my foot during longer efforts (see above for the fix). The heel is normal in width with a moderately stiff heel counter and little heel collar padding. I did notice the heel counter, so those with sensitivities may not do well here. Those who like stiff counters will appreciate it as it does a great job of locking the heel in. I did not have to lace lock the shoe, so security was quite good. The mesh is a knit material that does not stretch a ton and provides fairly good security. With the laces secured, the knit lines in the midfoot seem to lock things down well while staying on the lighter side for a trail shoe. Overall, the Ultra G 280 has an anatomic toebox with lower volume midfoot that still feels secure for trail efforts. 


The Inov-8 Trailfly is on the lighter end for a trail shoe and has a slightly bouncy midsole, giving it the versatility to pick up the pace of trails. The Graphene outsole and lugs are highly aggressive, making it an excellent choice for technical terrain or areas where grip is needed. I had the chance to test these on mud after some rain here in Southern California and found the grip to be excellent on both wet rock and wet dirt. The new nitrogen-infused FLYSPEED provides a decently cushioned sole for a shoe that feels so nimble and lighter than its listed weight. The foam itself is mildly bouncy on road and trail. It does not feel like a super foam but feels better than pure EVA foams. It is best described as a firmer and more sturdy mix between HYPERBURST and DNA Flash. It is not incredibly bouncy but does provide a cushioned feel underfoot. Pushing the pace makes the foam come alive a little more. This makes the Ultra.G 280 great for uptempo and some faster efforts on trail. It does have enough cushioning for moderate to long runs on trails. However, the more flexible forefoot may make it top out at half to full marathon distances for most people (if that). Those that want a nimble, quicker shoe with an excellent grip that can handle more flexibility will be able to take this shoe as long as their body can handle.

There is a heel bevel and a mild forefoot rocker. The heel transition is a little clunky, especially with the adapter flex causing a slightly odd transition through the midfoot. This makes landing farther forward in the Ultra G 280 more comfortable. The clunky heel makes the heel drop feel slightly higher than the 8mm listed drop (more like 9-10mm). The forefoot has a great transition thanks to decent flexibility and fantastic grip. The Graphene outsole grips extremely well and the lugs easily dig into most things. While it isn't the best option as a road shoe, I have used these as a door-to-trail option and the lugs have remained intact after 30 miles. While the Ultra G 280 is on the lighter end, I still expect the durability to be quite high thanks to the well-placed outsole coverage.

DYK? The end of INOV-8 shoe names indicates how many grams the shoe is.


The Inov-8 Trailfly Ultra G 280 is a neutral trail shoe. Outside of the heel counter that extends a decent amount forward, there are no major methods of stability. The midsole is fairly flexible, making it adaptable to a variety of terrain. While the adapter flex is angled in such a way it could facilitate motion laterally, it it somewhat uncomfortable and feels more like something to avoid. There are deep longitudinal flex grooves in the forefoot that may facilitate motion forward. However, the Ultra G 280 is really best for those who do not need stability and want a truly neutral shoe. 


Does a Trail Shoe Need a Super Foam?

The new FLYSPEED midsole is certainly comfortable and bouncier than many of the hard and stiff midsoles found in trail shoes. Inov-8 reports that it provides a 65-68% energy return. Energy return refers to how much energy a shoe is able to maintain from the force of the foot hitting the ground. A shoe that maintains all energy (100%) would bounce back all the energy that was put into the ground. This is not possible as things like heat loss cannot be contained, so 100% is not attainable. However, many companies are getting closer than ever expected to that number. The midsole is good for a trail shoe, but is far behind the majority of newer super foams on the market. EVA (traditional) foams are known to provide energy return in the 50-60% range. The majority of true super foams on the market currently provide upwards of 75-85% energy return (with some in testing providing far more). Most of these foams are used in road shoes, but Saucony PWRRUN PB and Nike ZoomX are already being used in trail shoes.

That said, one could argue that super-soft trail shoes are not necessary. Trails are inherently less stable than road. The dirt or softer materials provide more cushioning but also more movement. A soft shoe combined with a soft surface only increases instability. Therefore, it makes sense that a shoe like the Ultra G 280 would not use a super foam. It does not have a plate for stiffness and is actually quite flexible. Combining flexibility, softness and instability would be a disaster.

The Trailfly FLYSPEED midsole feels far better on trail than road. The Graphene lugs seem to add extra firmness on road, while they dig in and allow the midsole to shine more on trail. While not a super bouncy shoe like the many road shoes we are getting used to, it has enough cushioning and mild bounce to feel like it can pick up the pace. The narrow sole (especially midfoot) would probably not work with a super soft midsole, so perhaps this is the best option for a trail shoe. That said, I would still like to challenge Inov-8 to start thinking about more resilient and responsive foams. There are plenty of ways to add guidance or stability that were often seen in the trail world first (high stack, flared midsoles) if things get too bouncy and soft. I appreciate Inov-8's attempts at growth, but there is a little more work needed. 


True to Inov-8, the Trailfly Ultra G 280 is a unique shoe with a slightly odd fit for me. I have enjoyed it, but have a few suggestions of how to improve. The first is to fix the upper. The excessive pressure on the dorsum of my foot makes me think that either the tongue needs to be thicker or a little more height is needed in the midfoot. I have not taken this shoe above 12 miles and do not think I would given that pressure. Others likely do not have the same extensor sensitivity I have and should be fine for longer distances

The biggest suggestion I have is in the midsole. Mid 60% energy return is far below the leaders. I challenge Inov-8 to get that number up by a significant amount. With the Nike ZoomX trail racer coming to market soon and the Endorphin Edge already out, Inov-8 will have some serious competition. I would suggest decreasing the density of this midsole material, or consider using a higher-quality foam.

The final suggestion I have is to get rid of the adapter flex. It provides an awkward transition and makes the heel feel clunky in this design. A full ground contact midsole will be inherently more stable as there is more ground contact. There are other ways to facilitate motion, including many of the "guidance" methods we frequently discuss.


The Inov-8 Trailfly Ultra G 280 is a lighter trail shoe with a wide toe box, low fit, mildly bouncy new midsole and fantastic grip for a variety of aggressive terrain. The knit upper has a wide toe box, but also features a lower midfoot. Those with high insteps may need to avoid this shoe, while those with stable lower feet will enjoy it. Those that want some toe splay without being sloppy will enjoy the anatomic fit. The midsole is best for those who do not like super soft foams but still want a slightly newer midsole that has some mild rebound. The Adapter Flex still feels odd, making the heel feel more blocking and almost forces me to land on the forefoot for a better transition. Unless you need some forced midtarsal mobility, most people will like this shoe if they land farther forward. The flexible forefoot combined with lighter weight make this an easy shoe to pick up the pace in and transition through the front of the shoe. A solid option for faster running and training on trails without being too nimble, those looking to race half marathon trail distances or marathon trails if they land a bit farther forward will enjoy the Inov-8 Trailfly Ultra G 280.


Fit: B/B- (Upper sits low and causes extra pressure across the top of the foot. Requires relacing. Tongue potentially too thin for laces. Anatomic toe box is good without being sloppy.)
Performance: A- 
(Responsive midsole for a trail shoe with fantastic grip. Handles easy to technical terrain well. Lighter weight for a trail shoe allows for a variety of paces. Easy to run quicker in on trails with just enough cushioning for some longer efforts)
Stability: B [Neutral] (Standard neutral ride. Fairly flexible sole and midtarsal flex groove creates extra motion that will require extra ankle control. Not unstable, but not a guidance or stability shoe. )
DPT/Footwear Science: B/B- (Good effort with newer foam, but energy return and midsole material not truly high or bouncy enough to compete with true super foams coming to the market)
Personal: B (I want to like these more, but low sitting upper causes too much pressure on the tops of my feet. Relacing helps somewhat, but not my favorite upper. Midsole is great and grip is fantastic. Lighter weight for a trail shoe is great in the era of max stack height monster trail shoes. I challenge Inov-8 to bump their energy return in the FLYSPEED midsole into the mid 70% range, then we'll talk. 


Price: $185 at Inov-8

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Editor's Note: As always, the views presented on this website belong to myself or the selected few who contribute to these posts. This website should not and does not serve as a replacement for seeking medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist. If you are in the Los Angeles area, I am currently taking clients for running evaluations.

***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at Inov-8 for sending us a pair.  This in no way affected the honesty of this review. We systematically put each type of shoe through certain runs prior to review. For trainers and performance trainers, we take them on daily runs, workouts, recovery runs and a long run prior to review (often accumulating anywhere from 20-50 miles in the process). For racing flats we ensure that we have completed intervals, a tempo or steady state run as well as a warm-up and cool down in each pair prior to review. This systematic process is to ensure that we have experience with each shoe in a large variety of conditions to provide expansive and thorough reviews for the public and for companies. Our views are based on our extensive history in the footwear industry and years testing and developing footwear. If you are a footwear rep looking for footwear reviews or consultations on development, we are currently looking to partner with companies to assist, discuss and promote footwear models. Partnership will not affect the honesty of our reviews.

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