Inov-8 RocFly G 390 GTX hiking boots | Tested and reviewed

Bringing its trail running expertise to the hiking market, Lake District-based brand inov-8 has created an ultralight, super-comfy and mega-cushioned hiking boot with the RocFly G 390 GTX.

The headline stats are impressive: each boot weighs just 390g (men’s UK 8), the graphene-infused midsole feels really bouncy and energetic, and the wide toebox delivers comfort straight out the box. You also get a Gore-Tex liner and a tiny bit of stability and protection.

But we found this is far from the sturdiest three-season boot out there. In fact, it’s perhaps more of a ‘two-and-a-half season’ boot, if such a category existed. The light, modern style does compromise long-term durability, and some hillwalkers will want far more rigidity and better waterproofing in their boots.

However, if high comfort, low weight, and an energetic, speedy feel are your priorities, this lightweight walking boot is a winner, particularly for multi-day hiking adventures in milder conditions.

Upper

The upper of the RocFly G390 GTX is thin, soft and flexible. This is a double-edged sword. It means the boot is extremely comfortable – it fitted us like our favourite pair of trainers and there is minimal risk of rubbing, pinch-points or blisters. The downside is that long-term durability can never compete with stronger materials such as leather, and you don’t get much stability or support.

The ankle cuff provides a tiny bit of protection, but it is very flexible and it doesn’t rise as high as many other pairs. The heel cup doesn’t lock your foot in place particularly firmly, and the wraparound rand and toe bumper are not particularly stiff or strong.

The tongue is soft and padded, delivering good comfort, but the gusseted design is only connected to the main body of the boot lower down the tongue. This means the ‘flood level’ of the boot – the point at which water will enter the top of the boot – is set at about 12cm, compared to 16cm+ on taller 'boot height' models.

Consequently the inov-8 RocFly G 390 GTX has a clear niche. If you’re likely to be regularly sloshing through deep quagmires or scrambling up technical craggy ridges, where rigidity, stability and protection are paramount, this is not the boot for you. But, if comfort is priority number one, this light, flexible and super-comfy boot hits the mark.

Midsole

For a few years, it has been used in the outsoles of Inov-8’s footwear, but in this boot it has been infused into the midsole foam as well. Inov-8 says this approach is “scientifically proven to deliver 25% greater energy return”, as well as increasing the foam’s long-term durability.

This boot does indeed feel really bouncy underfoot, with excellent energy return and a springy rebound. Or, in other words, you feel fleet-footed and fast in these boots. This style may polarise opinion (will you love or hate it?), but it is certainly modern and cutting-edge.

We wore the Inov-8 RocFly G 390 GTX on a 9-day, 225km hike of the Haute Route from Chamonix to Zermatt in the French and Swiss Alps, and they really powered us forward for mile after mile, day after day. Even several months after that trek, the bounciness of the foam’s cushioning hasn't dropped off too significantly.

Outsole

The RocFly G 390 GTX’s outsole features Inov-8’s signature graphene grip, which is designed to deliver faultless traction over all types of terrain. The rubber lugs are 4mm deep and the tread pattern is relatively aggressive. We found the grip pretty solid, whether hiking on grass, mud, compacted trails or rocky terrain.

Another interesting feature is the groove in the outsole below the arch of the foot, which Inov-8 calls the Adapter-Flex. The brand says this enables the boot to “adapt and react to the terrain with the type of agility usually reserved for trail running shoes”. We couldn’t really judge this feature’s efficacy in isolation, but the boot certainly coped positively with the mixed terrain of a long-distance trail across the Alps.

Features

Each boot includes a waterproof Gore-Tex membrane, which keeps your feet reliably dry below the flood level, and provide reasonable levels of breathability so your feet don’t over-heat excessively. During our test walks, the waterproofing never let us down, but it’s important to remember that membranes are not infallible, particularly in lighter footwear, which is more vulnerable to wear and tear.

Keep them clean and reproof the fabric to maximise the longevity, but even so, a minimalist pair of boots like the Inov-8 RocFly G 390 GTXs will inevitably struggle to match the long-term waterproofing capabilities of a heavier leather boot.

The laces of the G 390 GTXs are quite basic, looping through perforated holes. They provide a nice comfy fit, but you don’t get any lace hooks for a tighter, more stable fit around the ankle. Also, the perforated holes are cut into the main body of the boot. The top three of these on each side, which lie above the tongue line, appear to be a water ingress risk. They are, quite literally, holes in the fabric of the boot, which is a little odd – although of course all boots have a massive hole for your foot to go in, so perhaps a few extra tiny holes won’t make much difference.

Price and competition

At £170, the Inov-8 RocFly G 390 GTXs are fairly priced, up to £100 cheaper than tougher, burlier three-season hiking boots from other brands. Its performance is excellent for a specific use – big mileage hikes in fairer weather, where comfort, cushioning and speed are essential. As such they are well-designed for national trails and long-distance adventures – but some hikers will prefer more protection, stability and rigidity.

How we tested

These hiking boots were tested by one of our top reviewers, James Forrest. James is well known in the outdoor world for undertaking huge challenges, such is climbing all 1,001 mountains across the UK and Ireland. He can be unfailingly relied upon to give his gear a proper thrashing.

James put the inov-8 RocFly G 390 to the test in European alps, hiking from Chamonix in France to Zermatt in Switzerland. It took him 9 days to cover the 225km route, so you can be certain that he put these boots through their paces.

Verdict

The Inov-8 RocFly G 390 GTX is a super-light, ultra-cushioned boot with trainer-like comfort – but long-term durability is compromised with such a lightweight build.

Don't forget to subscribe to the Live For The Outdoors newsletter to get expert advice and outdoor inspiration delivered to you inbox!

Get half-price digital OS Maps. Trail and Country Walking magazine members get 50% off an annual subscription to OS Maps for 12 months. Find out more here.