RHB Vaprtherm Socks

Although often overlooked, getting the right sock combo is almost as important as what boots you wear, as they affect both the eventual fit of your footwear and your foot’s overall ability to stay comfortable and blister-free. Get this wrong and you can end up with boots that feel the wrong size, cold feet (even frostbite), blisters and a whole host of foot nastiness – making all the thought that went into fitting the perfect boot totally pointless. Socks have improved greatly over the last two decades, primarily since Thorlo came onto the market, boosting competition and the development of new designs and fabric mixes. These days climbers can buy from a huge array of excellent socks from companies like Thorlo, Smart wool, Extremities and Patagonia, with weights ranging from gossamer-thin liners to Shackalton’esk Arctic socks big enough to hold all the kids presents at Christmas.

Traditionally climbers have gone for one thin wicking sock made from a synthetic fabric next to the skin, followed by a thick blended sock on the outside, perhaps adding two thick socks if it’s cold. Suffering from cold feet (or is that because I climb in cold places?) I’ve always tended to use the three sock approach. The problem is that if you wear too many socks you lose a margin of control when climbing, and if you carry a spare set the weight adds up. Also if your sock combo is at all tight you risk further reducing circulation as tests have found that even socks that appear the correct size can limit blood flow.

Another problem is that the switch to leather boots over the last few years has meant that on multi-day climbs sweaty feet can wet out your boots, meaning you either end up having to take them to bed with you or start each day with stiff blocs of ice on your feet. The obvious answer to this would be vapour barrier liners – which are big in the US – but these tend to bring their own problems, namely a loss of control (being slick they create more slide in the boots), and your feet can boil in them.

All this has led me over the last few years to wonder where the breakthrough was for our feet, as it seemed that technology had been applied to every other part of our bodies. Some people were thinking out of the box, using Mardale or Helly Hansen fibre pile boots as replacements for socks at high altitude, plus a few manufactures had brought out well-cut Polertech socks, but still, they didn’t quite hit the mark.

Then a friend of mine who’d walked solo to the North Pole mentioned some socks he’d used, which he claimed were by far the best technical sock on the market, having used just a single pair for over 72 days – with no liners, no vapour barriers or outer socks.

These socks come from a company called RBH in the states and are simply called Insulated socks, but of course, they are much more than just that.

These socks are made from a fabric called Vaprthrm and are basically thick and thin fleece with a vapour barrier membrane sandwiched in-between. They are designed to be worn alone, with no liner or outer socks, and removed at the end of the day to dry. Like any vapour barrier system, the idea is that when you reach 100% humidity within the sock your feet will stop sweating, and in a traditional sock combo, this barrier also stops both your outer sock and boot from getting wet. Unlike a traditional VB combo, this system is far slimmer, plus there is no slickness between the layers (all three layers are laminated together). A lightly brushed inner fabric stops your feet from getting that ‘foot in a plastic bag’ feeling, with the thin fleecy outer providing warmth and some cushioning. The socks are sewn together with the seams turned outwards, and although you’d expect blisters as long as they are fitted correctly they are blister-free.

Willing to try anything once I ordered a pair and used them ice climbing in New England, winter climbing in the Rockies and on a winter trip to Alaska. First of all, I was impressed that even after long days of walking to and from routes I never removed the socks to find that my feet had that ‘boil in the bag’ look about them – plus they were blister-free. In fact, at the end of the day, my feet always looked far better than they had with a traditional sock combo, even seeming relatively dry, proving that the vapour barrier concept did work. They were also very comfortable to wear, and fast-drying, simply being turned inside out and stuffed next to my base layer overnight. My inner boots and leather boots also stayed much dryer (they aren’t taped so some moisture does get out), making life much easier on bivvys or in supercooled tents. By far the best thing though was that the sock was much slimmer than my old sock combo, meaning I was able to achieve a much better overall fit for technical climbing, which also helped to reduce the tendency to overtighten my boots (which would lead to cold feet). Warmth wise I used them from above freezing down to -30ºC, and I’ve still got all my toes to prove they worked.

At the moment you can only buy these socks directly from RBH in the US (www.rbhdesigns.com) priced at $36 (about £20), and they prefer to custom fit them to your foot size via a faxed foot outline, although you can just order your shoe size.

Price: $36 Weight: 134 grams