My first impression of this shoe was incredulity. In photos it looked like a stiff and heavy shoe, one I couldn’t imagine would be comfortable to run in for long distances at all. It looked cumbersome, gimmicky and I couldn’t have been more wrong.

A black and blue trail shoe on grass with an inbuilt gaiter fasting above the ankle and a dial instead of laces

When the box arrived, and I lifted out a shoe, I was immediately struck by how light it was (370g). The next thing I did was bend the shoe in half – yes it was that flexible. Wow. How wrong I was. Trying the shoe on was an experience in itself. I haven’t used the BOA system before, and the combination of that, plus the built-in gaiter and inner shoe, it took me a few minutes to discover the helpful loop holes and wriggle my foot in!

The fit is more snug than you would expect a trail shoe to have. I’m used to having lots of room to allow a thick pair of socks or even two pairs, but you only need one normal pair of socks – trust me when I say your feet will not be cold.

Still distrustful of how they would feel running, I wore them for a dog walk/jog first and once again was surprised at their comfort. At first glance the upper appears to be neoprene and is very soft and malleable, but it’s actually a combination of two fabrics; the outer is Polartec Windbloc® and inner is WinTherm®.

According to Scarpa, WinTherm® is:

“Wintherm is a thermoregulatory membrane that keeps body temperature balanced, guaranteeing excellent breathability and insulating feet from the cold and the heat thanks to two combined technologies: insulation and reflectivity.”

Not content with this explanation, I did some further digging and found the material is used on the Continent in Safety Shoes and the reflectivity comes from a microfilm of aluminium inside the fabric.

The Polartec Windbloc® is better known for its use in jackets and this is the first time it’s been utilised in a shoe.

My feet get cold. My usual winter running attire is merino socks inside neoprene socks. Whilst those of you doing epic, Pennine Way, battles over 100 miles will differ, I think trying to keep your feet dry on shorter distances is a losing battle; my priority is to keep them warm and be prepared to change socks on the longer stuff if I’m out all day.

But with the Ribelle Run Kalibra G, the cold is no longer an issue. Standing in a puddle, it almost felt like I was wearing wellies – I couldn’t tell I was standing in water at all. No chill, no moisture, nothing. Just warm toes. One word of warning however; on running through a deeper patch of water, there was some ingress through the BOA dial and you can see from the photos that the upper layer has a circular opening to fit the dial through, so that isn’t waterproof. But they are so warm! Running through snow with warm and dry feet was a revelation.

That takes me to the BOA system itself. I haven’t used it before myself; again, I had a prejudice against the fastening. Usually, I re-thread my laces in a complicated system that allows for less pressure over the bridge of my foot but the ability to tighten with a heel lock at the top. Could simply turning this dial ensure a comfortable fit without pressure? Yes it could.

I was particularly wary when running across the steep camber of a hill – this has always been problematical for me as the lower forefoot tends to slip downwards and outwards against the side of the shoe. After a further, reassuring, crank of the dial, the BOA system held my foot in place comfortably. The system wraps all the way around your foot, including the heel, so your foot is literally “encased”. My other concern, that the wire system would break easily, or snap on a rock, and render the shoe useless, is also unfounded and although it’s early days, I fully expect it to remain sturdy.

For those who wear personal orthotics, I can confirm you can switch out the insole for your own. My flat feet have needed inserts for years and it is an important consideration when buying new shoes. The 4mm drop is neutral enough to appeal to most trail runners and the PRESA mid sole gives a comfortable level of cushioning without letting you lose feeling with the ground.

Presa is Scarpa’s own design:

“PRESA soles are created by Scarpa’s in house R&D team – and are designed to suit the specific needs of our shoes. From walking to running and everyday shoes our shoes (and their soles) have very different uses, so need different specifications in the soles.”

Combined with Supergum on the sole, the lugs are hefty enough to give confidence on the worst of terrain. Supergum is a rubber made with three compounds designed to give performance durability and grip and I was very happy running on both snow and rock.

The gaiter fastening at the top is a bit fiddly. The zip curves up the foot, then around the ankle in a bias cut. This makes pulling the zip all the way to the top, with a flap to tuck underneath, quite tricky. There isn’t a lot of stretch so if you have decent muscles on your calf it’s definitely worth checking they fit. Having said that, now that I know what to expect, the BOA fitting, the inner shoe loops to use to pull them on, and the fastening at the top are now done without thought.

ULTRA Magazine is always keen to do what it can for the environment, so it’s something we look for in others too. I was pleased to see that Scarpa have their own Green Manifesto, which includes a large percentage of production within Europe, solar panels for power and using recyclable materials. They have even created a shoe which is 100% biodegradable and for the other shoes, Scarpa offer a resoling service.

It didn’t take me long to fall in love with these strange shoes. Their comfort, grip and warmth make them the perfect winter shoe for where I live in the Peak District. I would buy a pair of these without hesitation. There’s no doubt Scarpa offer the highest quality and although this is reflected in the eye-watering price, if these shoes last the distance I think they are a game changing addition to a mountain and winter arsenal that any trail runner should consider.

“The RIBELLE RUN KALIBRA G is the trail running shoe for mixed terrain and extreme conditions, when cold, snow and mud demand greater protection and enhanced reliability. Suitable for medium-distance training, in winter or in summer on softer, more technical mountain terrain. The cutting-edge features of this shoe are the Wrap360 Lace System, developed in collaboration with BOA®, that allows a complete wrapping of the foot, both on the front and heel areas. And the first time that Polartec Windbloc fabric has been used in a shoe and provides unparalleled protection from the elements yet retains a high level of breathability.”