Saturday, November 06, 2021

inov-8 ROCFLY G 390 Lightweight Hiking Boot Review

Article by Alex Tilsley and Sam Winebaum

inov-8 ROCFLY G 390 ($210)


Alex: I think every thru hiker has probably experienced some amount of internal turmoil trying to decide between trail runners or boots. Boots feel like the responsible choice -- stable, grippy, and built to keep you from breaking your ankle when you hit a rock with 30 pounds on your back. But trail runners are comfy, they feel more natural, and they’re lighter, which matters when you’re spending all day walking. 

The ROCFLY G 390 aims to make that question a little easier with a shoe that aspires to take the best of both worlds, providing the stability and ankle support of a boot crossed with the agility and ground feel of a trail runner. 

Sam: When I "resumed" serious trail running around 2005 I gravitated to Inov-8's early models. From the rugged north of England the brand started specifically to create agile, well lugged trail runners, most of the more minimal variety. They were great!

After wandering a bit into CrossFit, OCR, weight lifting and such Inov-8 returned to trail running in a big way in 2020 with the Graphene Grip shod Terraultra G 270, a zero drop medium stack height all around shoe that was RTR's trail shoe of year, 

In 2021 they launched the more max stacked Trailfly G 300 Max (RTR Review) with not only a Graphene Grip outsole but graphene in the midsole for resiliency and a deep groove through the midsole the patent pending Adapter-Flex which, as named allow the front and rear of the shoe to hinge and to flow and bend over terrain and effectively so. At 12 oz / 338g its weight was felt and we felt it was best suited to the longest of runs and hiking more than day to day trail running.

The ROCFLY is essentially a mid-height boot version of the TrailFly G 300 (RTR Review) with the midsole and outsole identical. The only other difference is that the ROCFLY does not have the Boomerang TPU beads sock liner of the TrailFly substituting what appears to be a more standard EVA sock liner.

Inov-8 athlete James Forrest recently set an epic off roads record over the highest peaks in Scotland in them during a 500-mile adventure that took 16 days,15 hours & 39 minutes. You can watch his video take here.

Alex: I was excited by the prospect of the ROCFLY G 390, in part because I did my last thru hike, Vermont’s Long Trail, in inov-8’s Terraultra G 270 (RTR Review). I loved the fit and the feel of the Terraultra G 270s, but in retrospect they were probably not enough shoe for me on that particular trail. (I fell so often I started keeping a tally in my trail journal and trying to guess how many times I’d fall the next day, so at least it would be funny when I tumbled pack-over-heels into the mud.) The Long Trail is also a spectacular muddy mess, so those shoes hit the trash before I even took a shower, and I haven’t had a reason to look for a good thru hiking shoe since. (I did do a mini thru of Virginia’s Massanutten Trail this spring, but I just wore my Saucony Peregrines, which turned out the be a really, terrible, no good, very bad idea, and ended with me having to spend a day entirely inside because my blisters were so bad I couldn’t wear shoes.)

All of that is to say -- the prospect of the ROCFLY G 390 was interesting. Inov-8 described it as a shoe built for putting in long miles day after day, and even though it looked like a burly shoe, the relatively light weight and 6mm drop felt like the kind of specs that could really work for a long distance shoe. I, like many thru hikers (95% of whom seem to wear Altra Lone Peaks), tend to take a little bit of pride in only wearing trail runners, but the ROCFLY G 390 seemed to have enough trail runner characteristics that I wouldn’t totally feel like I was switching sides. Plus, it felt like it could be the responsible choice if I wanted to keep my feet and ankles happy for future adventures. I was excited to give them a try. 


Forgiving forefoot width, good for wide feet or feet that grow after days and days of hiking: Alex/Sam

Great in mud, and quick to dry: Alex

So much cushion forgiving and stable too! Alex/Sam

More flexible than your typical boot, more supportive than your typical trail runner: Alex/Sam

Very light for a full fledged supportive boot at 12.7 oz US9 with a big 30/24 stack height Sam


Tongue shifts, some issues with ankle support/pressure points Alex

Not much traction on wet mossy rocks, in test less than MegaGrip on the same rocks: Sam/Alex

Tester Profile

Alex Tilsley is a trail runner, long-distance backpacker, and adventure racer currently living in DC and finding dirt wherever she can. Alex has completed thru-hikes of the Colorado Trail, the Long Trail, and the Massanutten Trail, along with countless long backpacking trips and mountain summits. When she’s not running or hiking, Alex works full-time in education policy and part-time putting on trail races with EX2 Adventures

Sam is the Editor and Founder of Road Trail Run. He is 64 with a 2018 3:40 Boston qualifier. Sam has been running for over 48 years and has a 2:28 marathon PR. These days he runs halves in the just sub 1:40 range training 30-40 miles per week mostly at moderate paces on the roads and trails of New Hampshire and Utah. A long time hiker and snowshoer he is often in the rugged White Mountains of New Hampshire. He is 5’9” tall and weighs about 164 lbs if he is not enjoying too many fine New England IPA.


Approx. Weight: men's 13 oz / 369g  (US9)

  Sample: men’s 12.7 oz  / 360g US8.5 / EU41.5

Midsole Stack Height: 25mm heel, 19 mm forefoot 

Full Stack Height: 30mm heel / 24mm forefoot (not including 4mm sockliner)

4mm lugs

Available now. $210


First Impressions and Fit

I have to admit that on opening the box I was a little skeptical. These shoes don’t look like traditional hiking boots. The midsole is thick, and extends beyond the heel a bit, similar to what you see from some Hoka trail runners. The pink and black was also a little flashy for my hiking tastes, and it just looked a little bulky for a boot that evolved from a trail runner.

But man, that skepticism vanished as soon as I slipped my feet into these shoes. It felt like I was standing on pillows -- except, perfectly supportive pillows, with a little bit of bounce. The boots felt so lively I actually jogged up and down my apartment’s hallway because they just made me want to run.  And the fit, as I’ve come to expect from inov-8, was spot on. I sized up a half size above my typical running shoe size (6.5), because I often wear thicker socks when hiking. The size 7 left plenty of room for a thicker sock, and my heel wasn’t slipping, nor was I tripping over the toe. If I were planning a really long adventure, I’d probably go up another half size to accommodate the inevitable foot swelling, but for weekend adventures the 7 is perfect.

And for those, like me, concerned about width, the ROCFLY G 390 is pretty generous in the forefoot. It’s built on inov-8’s widest last (5 on a scale of 1-5), and while maybe not as wide as some Altras, it’s likely wide enough for all but the widest feet. (For reference, I typically wear a D width if I can get it, and I had no issues with inov-8’s #5 width in the G 270 on a 3-week hike.)

Sam: For sure we have a boot here. I immediately could sense the "mid height" part was actually functional. Often mid height near trail shoes extended collars are sloppy, too soft and flexible and actually less effective than low cut trail runners. Not so here. Squeezing the high collar and on the foot the stout support is clearly felt.

The fit is in indeed generous up front as Alex says and somewhat more accommodating than the TrailFly's and for sure many other hiking boots. Yet everything is well held with credit to the mesh, lacing and those protective and supportive blue overlays. It fit me true to size without any problem.


The upper is mostly a mesh knit upper with some overlays to add a layer of protection against rocks or sticks or whatever else you might encounter on the trails. 

The first weekend I took the ROCFLY G 390s out it was damp -- standing in a cloud damp -- and all the rivers were running high, and it is not an exaggeration to say I totally submerged the boots in water more than a few times. 

The knit upper was great, in this case, because the water didn’t get trapped in the boot, and though they weren’t totally dry probably ever in the course of the weekend, the squishy feeling of walking on wet towels passed pretty quickly, and I was able to hike comfortably in slightly-moist-but-not-soaked boots. It’s honestly about the best you can ask for when you end up knee-deep in the river. 

Drying capabilities aside, the overlays around the edge of the boot and the toe provided a nice hint of structure and protection without ever getting in the way. My one issue with the upper is the tongue, which, try as I might, would not stay centered, and kept sliding over to the outside. Normally this might just be a nuisance, but on my left foot, the movement of the tongue left my ankle in direct contact with the back side of the lace hook (the metal bit on the inside of the ankle collar), which started to feel intrusive as the miles piled on. If I were taking these on a real long hike, that’s something I’d likely try to solve for, maybe with a little duct tape over the back of the hook. 

Sam: I would only add to Alex's fine upper comments that I had neither pressure from the lace hook or any slipping of the tongue during my first hike on rocky dry terrain. 

I cannot recall a mid height book that is so light with such an effective high collar, flawlessly secure lace up and accommodating toe box. The blue overlays not only protect the lower part of the upper but provide a kind of bathtub structure of support and toe protection front to back. The firmer EVA sockliner in place of the Boomerang bouncy sockliner of the TrailFly I felt provided a touch more support and stability where foot meets platform, vital in a boot especially when carrying a heavier pack


One word: Wow!

Men’s Colorway

Okay, more than one word: The midsole uses inov-8’s graphene-enhanced G-FLY foam, which inov-8 claims has a 25% energy return and is more durable and resilient  than standard foams. I don’t have enough miles on the shoe to say much about whether it wears or not, so I’ll put that aside. 

Obviously energy return is hard to measure, but honestly, I’d believe it. This shoe has a bounce that I didn’t think I’d like in a hiking boot until I tried it. Traditional hiking boots are firm and inflexible, and the ROCFLY G 390 is neither of those things. The midsole flexes with your foot -- in part because of the Adapter-Flex grove (more on that later) -- and cushions every step, providing a soft but snappy feel underfoot. You’ll know the rocks are there, but the shoe molds around them and softens the step so much you just keep on rolling.  

Sam: Neither overly firm nor stiff as Alex says. Lots of forgiving cushion here with some bounce yet a ride that is no way mushy or unstable. An ideal midsole for many long days on trail. I wish I had had them for our 200 mile trek across Switzerland with its many miles of pavement and hard surfaces.


I feel a little bit like my testing of the outsole was unfair (see above re: knee-deep water crossings). The outsole has aggressive 4mm lugs, and is made of inov-8’s Graphene-Grip rubber, which the company claims is the “world’s toughest grip.” And it did feel tough on rocks, roots, mud, and even wet fallen leaves. 

But it was no match for wet rocks. Maybe nothing is! But I had been so impressed with the grip I decided to trust the shoe on a very slick water crossing, and that was a mistake. Suddenly, I was ice skating across the creek. You can imagine how that ended. 

Still, I’d trust this outsole for just about any type of hiking. And if you do plunge into the creek, at least you know the shoes will dry pretty fast! 

Sam: The Graphene Grip outsole is outstanding on any surface but one and contributes to the cushion of the boot. One senses that the midsole and outsole are all of a piece in terms of feel, no disconnects and the deep Adapter Flex and groove aligned with the bones of the foot allow not only a smooth flow on moderate terrain but incredible grip and security on very steep rock.

The "but" here is that on wet smoother rock with a sheen of moss or other organic material such as those constant drips out of cracks as shown above there is no traction at all and far less than MegaGrip from Vibram. We tested this during our hike with my wife in a shoe with MegaGrip going over and holding on the same wet rock I couldn't;t at all on.


Imagine hiking all weekend in a fresh pair of your favorite long run shoes but not worrying about spraining your ankle if you hit a rock or root sideways. 

Hiking in the ROCFLY G 390 in some ways felt luxurious. I’m not sure I’ve ever worn a hiking shoe -- trail runner or boot -- that was at once bouncy, flexible, supportive, and grippy. (And all at a relatively light weight, too!) The way the midsole and the outsole work together make for a really distinct ride that makes you want to just keep walking and walking. 

The outsole has vertical grooves cut into the rubber to allow the metatarsals to move independently, which makes the ROCFLY G 390 more agile than your typical boot. At the same time, the midsole has what inov-8 calls an Adapter-Flex groove -- 10mm deep and visible on the outsole -- that breaks up the midsole at midfoot and allows for some flexibility. 

I tend to hike short, steep hills on my toes, and because of the adapter-flex groove I was actually able to get up on my toes and not feel like I was fighting the shoe. It also made for a softer and more natural feel downhill, as the shoe rolled with my stride, rather than landing flat. These sensations aren’t necessarily novel if you’re used to hiking in trail runners, but flexible and agile are certainly not words I’d use to describe most boots I’ve hiked in. 

I did have occasional issues on off-trail downhills with my foot sliding a little bit in the boot. I couldn’t seem to get the laces tight enough to really feel secure on steep, off-trail terrain. But that probably just means I’ll stick to trails with the ROCFLY G 390, which is perfectly fine by me.

Sam: Again I concur with Alex!  "Bouncy, flexible, supportive, and grippy. (And all at a relatively light weight, too!) The way the midsole and the outsole work together make for a really distinct ride that makes you want to just keep walking and walking."

Part of my test hike with friends involved this boulder field on Mount Moat in New Hampshire

The ride is clearly ideal for not only for any day hike but for many day treks and for that matter uses where you are standing on your feet all day. And recall, it took James Forrest to that incredible 500 mile off roads record across the most rugged parts of the UK in less than 16 days. I can see how!

Conclusions and Recommendations

My typical measure of a thru-hiking shoe is how much I dread putting it on on day 5. I’ve yet to get the ROCFLY G 390s on a 5-day trip, but can say that on a 3-day trip, not only did I not dread putting them on, I actually didn’t want to take them off. 

Yet, even though the ride felt great, I’m a little torn as to whether I’d take these on a really long hike. The ankle-rubbing situation is something that could get annoying in the long run, and as much as these have trail runner features, it’s still clear that you’re wearing a boot. They’re also pretty pricey, going for $210 -- that’s steep if you have to buy a few pairs to get through a really long trail. I hope to test them on a mid-length trip in the spring, and hopefully then will have a clearer conclusion then. 

Regardless of whether they end up being my thru-hiking shoe, the ROCFLY G 390 is definitely going to be my go-to hiking and weekend backpacking shoe. For those who find boots too boring and inflexible but trail runners too minimal, or who want a boot they can run in, or just want better grip while also feeling like you’re hiking on bouncy pillows, I think the ROCFLY G 390 is a superb new option. 

Score: 9.5/10

Ride 10/10 

Fit 9.2/10 (fit was great, but having the lace hook dig into my ankle was not)

Value 8.5/10 (if these really last longer than most shoes, I think the pricetag could be worth it, but $210 will understandably be hard for some hikers to stomach)

Style 9/10 (I’ll admit they grew on me over time)

Traction 9.5/10

Rock protection 10/10

Sam: By adding a supportive higher upper to the TrailFly G 300's superbly cushioned and stable underfoot platform while only increasing weight a bit more than 1 oz / 29 g to 13 oz / 369g, Inov-8 has delivered a very light very capable hiking boot that if you wanted to you could actually also run in. It is not a waterproof breathable lined boot by design as the membranes add weight, at least 1 oz, and are slower to drain and dry. Short of deep cold snow winter hiking uses, I am totally fine with this choice. My only knock on the Rocfly is the pricing and the notably poor grip on that very specific greasy wet rock. 


There is no question this is the most comfortable hiking boot top to bottom (cushion) that I can recall. It is an ideal choice for both long and short hikes as well as travel and any kind of long day on your feet.

Sam's Score: 9.41/10

Ride:9.7(30%) Fit:9.6(30%) Value:8.5(10%) Style: 9(5%) Traction: 9(15%) Rock Protect: 9.7(10%)

The ROCFLY G 390 is available from Inov-8 HERE

Tested samples were provided at no charge for review purposes others. RoadTrail Run has affiliate partnerships and may earn commission on products purchased through affiliate links in this article. These partnerships do not influence our editorial content

The opinions herein are entirely the author's

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Skidad said...

Interesting boot if that’s what your after. I tried on the regular G300 and didn’t like the bit of pressure I felt on my pinky toe sides (men’s 12). Inov8 uses a somewhat curved last (along with many manufacturers) that drives me nuts. People’s feet aren’t curved last I checked. Puts unnecessary pressure on the outside toes.
I would suggest you try some Topo’s but only the the ones with the MegaGrip sole compound. This stuff is exemplary on wet slick rock and technical terrain (White Mountains are my testing ground).
I would really enjoy an A/B test of the MegaGrip vs the Graphine compound as that’s advertised as really grippy. Not sure I want to pony up the money for a G300 (not the boot) myself to test this.
I’ve also tried the Lone Peaks and again not sufficient grip in technical terrain and honestly although I’m not a through hiker (on the list) I’d be more inclined to use their Olympus that has more cushion and MegaGrip on the sole. Durability is usually the Altra’s downfall.
A shoe you might consider trying is the VJ Ultra. It’s their highest cushioned shoe, built tough and the grip of their shoes is insane, incomparable. You can just get away with things you can’t with the majority of shoes. Total trust. I think VJ should make a mid height trail runner/fast hiker.

Alex said...

Skidad: Love the idea of A/B testing the Topo MegaGrip and the inov-8 Graphene. I haven't hiked in a Topo yet, but love the fit of their road shoes and would be interested to see how the boots compare to inov-8. The VJ Ultra sounds interesting, too!

Altras to me have never felt secure enough. I have a wider foot so appreciate the space, but on technical stuff, I want to feel secure in the midfoot and not have my foot sliding to the side of the boot. Both inov-8 and Topo seem to have a better midfoot fit, at least in my experience, though I hear you on the curved last. By the end of one longer hike I opted for a $7 pair of used shoes 2 sizes too big because it was the only thing that didn't cause pressure (and blisters) on my toes.

Sam Winebaum said...

Hi Alex and Skidad,
I will be joining Alex on the review shortly but wanted to report on my hike yesterday South and Middle Moat in the Whites. This is by far the most comfortable and capable mid height boot I have ever tested with superb cushioning and mostly superb grip... Wet rock, dry rock etc... as with the G300 the combination of a softer midsole and outsole, Adapter Flex, and the G Fly foam was outstanding but... on those constant drip areas over wet granite where some gooey organic stuff forms the grip was terrible. My wife had a MegaGrip outsole and had no issues on that kind of rock.
Sam, Editor

Skidad said...

Thank you Sam and I believe there was my answer. The MegaGrip is just really good, the VJ takes it to a whole different level. It’s addicting if you like technical terrain and like to push yourself.