Thursday, April 11, 2024

Inov-8 Trailyfly Multi Tester Review: 9 Comparisons

Article by Jeff Valliere and Mike Postaski

Inov-8 Trailyfly ($150)


Jeff V:  The Inov-8 Trailfly is an all new model from Inov 8, with a new foot shape design for all day comfort, yet with great security and with soft yet stable cushioning on a full stack height of  29mm heel / 23mm forefoot which is enhanced by a Boomerang TPU footbed and very good traction. It is a great all around and versatile shoe, equally at home running door to trail, buffed trails and dirt roads, and all the way up the mountain into more technical terrain.  

They make for a great daily trainer that, while not the fastest shoe out there, can easily handle fast running on just about any trail.  In addition to having a more generous fit foot shape design, they come in 2 widths, standard and wide.


Comfort, roomy yet secure fit (and width options), cushion, traction, protection, trail feel - Jeff V

Full coverage, yet flexible outsole Mike P

Comfortable upper, especially around tongue area Mike P

Width options Mike P

New Boomerang insole is lighter and more flexible Mike P


Styling - Jeff V

Slight loss of flex around midfoot Mike P

Heel hold could be better, could use some inner bolsters Mike P/Jeff V

Most comparable shoes

Inov-8 TerraUltra G270

Inov-8 TrailFly Speed

Topo MTN Racer 3


Altra Timp 5

Salomon Genesis


Approx. Weight: 10.2 oz  / 289g (US9)

Samples: men’s  10.6oz /302g US 10, 10.4 oz / 294g US 9.5

Stack Height: men’s 29mm heel / 23mm forefoot ( 6mm drop spec) 

Platform Width: 85mm heel / 62mm midfoot / 112mm forefoot

$150 Available now

First Impressions, Fit and Upper

Jeff V:  I have tested/reviewed a few pairs of Inov 8 shoes in the past and while they are fine shoes with good grip and secure uppers, they have never really landed for me for some reason.  

Inov-8 have really upped their game though this year with several new models such as the Mudtalon Speed (RTR Review), the TrailFly and the TrailFly Speed.  

With a 29/23 stack, it is by no means a max cushion shoe, but has ample cushioning for long days on the trail.  Notable is the foot shape design, such as Topo and Altra have.  In my opinion it is much more functionally closer to Topo, where there is ample room in the toe box for overall comfort, splay and swelling, yet still provides a very good foothold, even in technical terrain.

Fit is overall true to size, with very good hold in the heel and midfoot and as mentioned above, there is a wider toe box to allow for some wiggle room, yet the upper remains very secure.  I only notice a slight bit of waver when running steep off camber sidehill situations or when running very fast in technical terrain, but it is reasonably manageable.  T

he Trailfly comes in standard and wide fit, where for my narrow, low volume foot, I went with the standard fit which is perfect.

The single piece Air Mesh upper is breathable, well protected and comfortable with “Met Cradle” overly strips providing added an extra supportive locked in feel.

The toe bumper is thick and protective, warding off any stubs and bumps.

The heel collar is well padded and the heel counter is semi flexible, generally secure and supportive, but could use a little more structure.

The tongue is well padded and gusseted as well.

Mike P: I haven’t run in an Inov-8 shoe in a while, but I did love the Terraultra G 270 (now called Trailfly G270) when it first came out. This shoe, as well as the new TrailFly Speed (RTR Review soon), seems to be something of an iteration of that G 270. The new TrailFly notably incorporates a 6mm drop, which does feel noticeable in comparison to the lower 4mm of the TrailFly Speed and the zero drop of the older G 270.

I have found in the past that Inov-8’s sizing tends to run a bit small/short. I’ve typically run in size US 10.0 for Inov-8 but I received the TrailFly in US 9.5. 

It definitely runs short - my toes are pretty jammed up in the front, even with my most ultrathin socks. It’s passable for testing, but just so. On flats and inclines they’re ok, but any type of descent and they’re just too short up front for me. I would need a US 10.0 to make them runnable beyond testing. 

As far as the new Standard/Wide fit, it’s hard for me to get a read on it with the length not being correct for me. I do have both the TrailFly and the TrailFly Speed in Wide fit. The Wide fit is more noticeable in the TrailFly Speed - pretty much on par with a Topo and almost Altra-wide. I like the fit for comfort, but if I wanted a more dialed in fit for added security, I think the Standard fit would work better for me at a US10 . I think having the width option is great and should accommodate almost all foot sizes.

That being said, Jeff V will take the lead on this review, and I’ll focus more on the comparison aspect between the two new models in our upcoming TrailFly Speed review.

Midsole & Platform

Jeff V:  The new Powerflow Pro foam midsole is light, well cushioned and responsive, providing a quick, smooth ride with very good protection and overall performance on varied terrain.  I do not find the Trailfly to necessarily inspire speedy runs, but they can easily get up and go when you ask them to and perform very well at any speed and are a quite versatile everyday trainer.  

Adding to the cushioning and comfort is a new, lighter version of the 6mm Boomerang footbed that “features hundreds of expanded TPU beads that compress and spring back for more energy return and cushioning”.  

Also in the mix for added protection is a flexible fingered Meta Shank rock plate that allows the feet to move naturally and experience a nice level of trail feel.  Whether I am running my daily 60-90 minute run, or getting out for a full day of running or hiking, the Trailfly can handle just about any duration run without feeling the least bit beat up.

Mike P: The new Boomerang insole is a standout feature of the new TrailFly. It has actually been redesigned and improved from the previous/original Boomerang. It’s now both lighter and more flexible. I weighed them at 56g/pair for my TrailFly Speed insoles (US 10.0, wide). I weigh 60g/pair for a set of my old Boomerang insoles (US 10.0, regular). It doesn’t seem like much, but I do notice the difference in weight. 

[New - left, Old - right]

Either the beads or possibly the filler material seems to be lighter. They are also more flexible, which is also noticeable on the run. I’ve swapped my original Boomerangs into many shoes, and there was alway some loss of flex when using those. This newer insole should alleviate or possibly eliminate that consideration.

[Old Boomerang insole on top of newer, wide version Boomerang - the new insole on the bottom is 2g lighter despite being larger in volume]

I like the feel of the new Powerflow Pro foam. As Jeff says, it doesn’t “feel” super speedy, but it also doesn’t feel slow or mushy either. It falls somewhere in the middle in terms of responsiveness, and the shoe definitely feels more protective underfoot than both the G 270 and the TrailFly Speed. I never feel like I’m bottoming out in the midsole foam, which is something I felt with the G270. 

I don’t know what the exact orientation of the “Meta Shank” rock plate is but it is fingered up front to follow the toe bones. 

It does not feel like a thick plate, and it also doesn’t feel stiff under the midfoot. If anything, I noticed some stiffness under the arch of the foot, more towards the heel area. When landing on that spot I felt some instability at times, whereas I had better flex and feel under the forefoot. 


Jeff V:  The outsole features Inov 8’s Graphene Grip sticky rubber compound with  4mm chevron shaped directional lugs.  Traction has been superb on all terrain and conditions I have run on, from wet to dry, sandy, muddy, snowy, frozen snow, Utah sandstone, scrambling, etc…  Even when running loose, steep off trail, they grab quite well.

The lugs are still low profile and broad enough to perform well on the road, making them a versatile road to trail to mountaintops sort of shoe.  

The Meta Flex groove up front helps with flexibility on technical terrain and also help with propulsion at toe off.  Durability of the outsole is proving to be above average so far.

Mike P: Durability has been proven with Inov-8 graphene outsoles. I put 395 miles on my first pair of G 270’s and the outsole was still in good shape, while the midsole was fully packed out. The TrailFly outsole is full coverage, which is really great for protection. Yet the orientation of the lugs allows for plenty of flex, especially under the forefoot. 

The Meta Flex groove that spans across the entire forefoot does a good job of maintaining a smooth ride, even though there are no breaks in the rubber underfoot. 

Ride, Conclusions and Recommendations

Jeff V:  I’ll be honest that my first impressions were not overwhelming, perhaps because of past mediocre experiences and they are admittedly not a shoe that you put on and you are just itching to go fast in them.  However, I was surprised on the first run how much I liked them and as I ran in them, I liked them more and more, to the point where testing or not, I will be reaching for them regularly for my daily runs.

The Trailfly provides a smooth, lively and predictable well protected ride on a wide variety of terrain, from door to trail to the high mountains.  

While I do not necessarily need, or seek out a specifically “foot shaped” shoe, I appreciate the added room and comfort for most day to day training on the trails, as they are very secure overall with only a little bit of waver when side hilling steep terrain or at fast speeds in very technical terrain.  The Trailfly is an excellent day to day trainer or even racer for some and I would consider it to be versatile enough if you are looking for a one shoe quiver.

Jeff V’s Score: 9.4/10

Ride: 9.5, Fit: 9.5, Value: 9.5, Style: 8, Traction: 9.5, Rock Protection: 9.5


Mike P: When thinking about the ride of the shoe, I can’t help but think that it feels like a beefed up G 270. The G270 is more dynamic, firmer and responsive, mostly due to the fact that it’s lower to the ground and also zero drop. With that shoe, over time, I felt like the zero drop was a bit too much of a strain, and also the insole packed out after a while and it felt thin under the forefoot.

This flavor of TrailFly alleviates both of those issues. There’s more stack at 29/23mm, and the 6mm drop is smoother and doesn’t strain the lower legs. There’s noticeably more cushion underfoot, especially for me, under the forefoot. The Powerflow Pro foam feels similar to Altra’s EGO Max - somewhat responsive, somewhat lightweight, but not overly dynamic in character. 

Overall the ride feels smooth, as opposed to dynamic and agile. Here again I defer to Jeff for his technical assessment, as my incorrect sizing didn’t allow me to push them too much. If I had to guess at true, ideal sizing for me - I’d go with US 10.0 regular fit. 

They don’t feel as stable as they could be - as mentioned earlier, I detect a hint of stiffness under the midfoot/front of heel. If I had to pinpoint an instability point under the shoe - that would be the area. But If you can manage solid forefoot placements, you’re good to go, as there’s plenty of flex up front and no lateral instability.

Another area that could be improved is the heel area - the interior is pretty vertical, without any real bolsters around the heel. The fit of the shoe does manage to keep the heel seated, but it seems to rely on pressing the heel into the rear of the shoe as opposed to holding the heel down. I think loosening up this pressure and perhaps adding some interior padding would really round out the comfort level of the shoe.

This is a solid all-around shoe from Inov-8. For me, it hits squarely in that middle ground of everyday training - not overly cushioned, and not overly thin. It has some range for quicker runs, and also to go a bit longer if needed. Keep an eye out for our review of the TrailFly’s sibling - TrailFly Speed. I’ll take a more comparative angle in that review.

Mike P’s Score:  8.88 / 10

Ride: 8 - Smooth and comfortable, but nothing really stands out

Fit: 9 - Properly sized, you should be able to dial in a good length/width combo

Value: 9.5 - Outsole no problem, midsole should hold up longer

Style: 9 - I like the gradient look, and overall color scheme 

Traction: 9.5 - Inov-8 knows what they’re doing here

Rock Protection: 9.5 - Really good and still flexible 

Smiles 😊😊😊

9 Comparisons

Index to all RTR reviews: HERE 

Inov-8 TrailFly Speed (RTR Review soon)

Mike P (10.0): Stay tuned for our upcoming review. The Speed flavor is noticeably closer to the ground, and seems like it has an even wider fit. It’s listed at a 4mm drop, but rides almost like a zero drop shoe. It’s very different from this TrailFly - it feels much more minimal.

Inov-8 Trailfly G 270 (RTR Review)

Mike P (10.0): The TrailFly is a beefed up version of this shoe. It loses some dynamic feel, but adds noticeable cushion, drop, and protection. The upper is also better and more comfortable. The G 270 had some rigid edges around the ankle collar, andthe tongue was a bit thin. They leaned a bit more into the comfort side of the spectrum with the TrailFly. The wide fit of the TrailFly is wider than what they called the “wide” fit of the G 270. If you want to dial it in a bit, you can pick the Standard fit.

Topo MTN Racer 3: (RTR Review)

Jeff V:  This is the first and most obvious comparison that comes to mind for me.  Both shoes are about the same weight, same price and of course both have a more foot shaped design that is not as extreme as Altra, but functionally useful and welcome while providing good foothold and security.  The Topo, at a few grams less even, has 4mm more stack height and feels a bit more lively to me, while the Trailfly has a bit better ground feel and stability, while still providing excellent protection.  Traction is comparable.  

Mike P: This shoe also came to mind for me, the most obvious difference is that the Topo feels much softer underfoot. It also seems to be more flexible throughout, especially under the midfoot. TrailFly gets a big edge with its new Boomerang insole - it gives the shoe a better connection to the ground. Topo introduced a TPU insole of their own in the upcoming Pursuit 2, so I hope they will do the same with the next MTN Racer. 

Salomon Genesis: (RTR Review)

Jeff V:  Again, close in stack height and the same price, the Genesis is lighter with a quicker, more dynamic ride and a more substantial, well cushioned/protective feel.  The Genesis has more substantial lugs, while the Trailfly with Graphene grip compound has slightly better grip overall.

Mike P: Agree with Jeff - the Genesis is overall a better shoe. The cushioning feels softer, yet also more dynamic. I did find them slightly tapered up front in the toebox, so that’s a consideration if you’re thinking about Inov-8’s wide fit. Edge to the TrailFly in traction and durability, but the Genesis is still pretty good in that department.

Inov8 Mudtalon Speed: (RTR Review)

Jeff V: The Mudtalon is lighter and more stripped down, narrower, with a lower stack and a thin upper that does not retain water.  Both are foot shaped, but it is much more apparent in the Trailfly than the Mudtalon and both come in standard and wide options.  Beyond those major differences, the Mudtalon has incredibly aggressive 7mm lugs that are superior (to any shoe) in loose junk, mud and soft snow.

Brooks Cascadia 17: (RTR Review)

Jeff V:  The Cascadia is a great all around, do everything shoe, with more cushioning and protection underfoot, but with not as good ground feel. The wider toe box of the Trailfly is welcome on longer days or for those with wider feet.  The Cascadia has been creeping up in weight (12oz for my US M10) and this is very noticeable with the Trailfly at a considerably lighter 10.6oz /302g US 10 .  Trailfly has superior traction and outsole durability.

Saucony Peregrine 13:  (RTR Review)

Jeff V:  Close in stack height, weight and price, so another good comparison.  The Trailfly has better ground feel and flexibility and better sticky rubber for overall better grip, and despite the slightly more aggressive lugs the Peregrine is known for. This said the  Peregrine with a more secure fit, feels more competent in technical terrain, off trail, rock hopping, etc…

Altra Timp 5 (RTR Review)

Mike P (9.5): The shape of these shoes is very similar, but note the sizing difference here. My Timp 5’s are perfectly true to size, but I’m totally jammed up in the same US 9.5 for the TrailFly. I would need a 10.0 in the TrailFly for an equivalent fit. The Altra is slightly wider, but not that much. The TrailFly’s upper material is more flexible and breathable, and holds just as well. The Altra’s foam feels more dynamic, while the TrailFly feels vaguely similar, but not as good. Altra of course is zero drop, so if you’re looking for a Timp-type feel with a drop, the TrailFly is probably your best bet. 

VJ XTRM 2 (RTR Review)

Mike P (10.5): Putting this one at the end, since the comp is not as close as the others above. The VJ is much narrower in the upper, and also narrower on the ground, allowing for more foot precise placements in technical terrain. It’s firmer underfoot with a bit of a stiff ride and flex. The TrailFly is much smoother - better on trail, while the XTRM is of course better in “extreme” off-trail situations.

The Inov-8 Trailfly  and Trailfly Speed available now at Inov-8  & at our partner
Use our code RTR235 for 5% off all products

Tester Profiles

Jeff Valliere loves to run and explore the mountains of Colorado, the steeper and more technical the better. He has summited all of the 14ers in the state and can be found on mountain trails daily, no matter the weather, season, conditions or whether there is daylight or not.  On the side he loves to ski (all forms) bike and hike, often with his family, as he introduces his 12 year old daughters to the outdoors. Jeff was born and raised in New Hampshire, but has called Colorado home for over 25 years. He is 5’9” and 145 lbs.

Mike Postaski currently focuses on long mountainous ultras - anywhere from 50K up to his favorite - 100M. 5'10", 138 lbs, midfoot/forefoot striker - he typically averages 70 mpw (mostly on trails), ramping up to 100+ mpw during race buildups. A recent 2:39 road marathoner, his easy running pace ranges from 7:30 - 9:00/mi. From 2022-23 Mike has won the Standhope 100M, IMTUF 100M, and Scout Mountain 100M trail ultras. He also set a CR of 123.74M at the Pulse Endurance Runs 24H and completed the Boise Trails Challenge on foot in 3 days 13 hours, besting the previous record by 7 hours. Mike's shoe preferences lean towards firmer, dense cushioning, and shoes with narrower profiles. He prefers extra forefoot space, especially for long ultras, and he strongly dislikes pointy toe boxes.

Samples were provided at no charge for review purposes. RoadTrail Run has affiliate partnerships and may earn commission on products purchased via shopping links in this article. These partnerships do not influence our editorial content. The opinions herein are entirely the authors'.

Comments and Questions Welcome Below! Please let us know mileage, paces, race distances, and current preferred shoes

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Gregor said...

Hello, good as allways. Can you compare them to Merrell long sky 2? Thx

Anonymous said...

Ever try the Boomerang footbed in the Timp 5? I think that would be a nice set up for 100’s.

Mike P said...

I've tested Long Sky 2 (Matryx version - not the regular one). The LS is more flexible underfoot - there's no rock plate in the mix. It's also noticeably lighter (8.8 vs. 9.9 oz). Its a much narrower fit, but I have no issues because the Matryx upper holds the foot very well. The TrailFly has more cushion, so feel softer, especially descents with the added foam under the heel. I do think the Merrell is a much better overall shoe though, it's so light and fun to run in. It's a faster shoe. But if you need space up front, the TrailFly wide option could work well.

Haven't tried the new insole in the Timp 5, but it would definitely fit fell. Definitely a good setup for a 100. Just a touch more cush, and the feel will remain consistent throughout the long race.

Ante said...

Very interesting shoes from Inov8, great review!
Hows the wet weight and drainage?
You tested Vj Maxx 2, it should be comparable shoe? Would love to hear of main difference.

Mike P said...

Wet weight is pretty good - the upper has a lot of synthetic mesh and overlays so it doesn't absorb much. Of course the TPU insole doesn't hold anything either.

VJ MAXx2 is an incredible shoe - 8.6 oz appropriately sized for me vs. 10.4 oz in my TrailFly sample which is way to tight. Big difference is that the midsole foam of the VJ feels softer, yet is also responsive. TrailFly foam is denser, less dynamic, but it does get the edge in stability if you're focused on technical terrain. MAXx2 is so much fun to run in "lighter" conditions though!

Anonymous said...

Thanks, will try the Maxx2 now when they start shipping

Jerry McIntire said...

I ran the Innov8 Terra Ultra 260 which I liked. The outsole was exceptionally durable but the upper separated from the sole before the shoes were worn out, so I haven't bought an Innov8 since. Has durability improved?

Mike P said...

Jerry- I can't really say because I won't be able to put more miles in them due to the incorrect size that I have. The material and construction does seem similar to the G 270's that I had - which lasted quite a long time without any issue for me.

Anonymous said...

FYI the midsole is just a slab of CMEVA, like the last ones.

Nothing supercritical or infused.

Honestly these four new shoes from Inov8 smack of saving production costs. Maybe if they spent less money paying a consultancy firm to change their logo they might be able to afford a nitrogen infused midsole and a competitive weight, upper material, outsole... etc

Anonymous said...

Thank you for your extensive review!I was wondering how these compare to the Hoka Speedgoat 5. Running on Inov-8 g270 now, but need a little more protection on the forefoot.