Adapting an SNS-XADV backcountry ski boot for mountaineering

Background

The more mountains I climb in Alaska the more I realize that there is often a gray area between the end of the approach and the beginning of the climb. So many objectives lie five to ten or twenty plus miles away from the highway and are not always accessible by snow-machine or ski plane. Besides, the approach is part of the experience! However, the wrong gear can often make that experience a nightmare.

Thus, my attempts to meld mountaineering and Nordic back-country skiing continue. Adding comfort, cutting weight, and improving the entire experience from approach to summit is what I'm most passionate about. Why should we be forced to shuffle along in heavy, cumbersome AT skis and skins on nominally flat terrain in boots that don't even allow you to flex your toes? If you're like me, you've thought "there's got to be a better way."

Climbers, meet the Salomon XADV-6 boot. Though not designed for climbing or mountaineering, it is used by back-country skiers who cover long distances on Nordic skis.  You can skate ski, classic ski, or boot pack with these bad boys. They are also tantalizingly comfortable, especially compared to an alpine touring boot. However, the flexible toe, which is the key feature that makes this boot so satisfying to ski in, makes for substandard mountaineering performance. Not to worry!

The Prototype

Modern mountaineering boots are equipped with a built-in steel shank, which extends the length of the boot sole and allows for front-pointing without flex on steep terrain. Take a quick look at the sole of the XADV-6 boot and tell me when you see...

...a relief cut into the sole accommodates the SNS-XA binding, which is ultimately used for power transfer through the heel when turning. Why not reinforce the boot with a removable shank? This would allow for optimal touring performance while giving the climber an option for better climb-ability when the going gets steep. Ta da!

With the help of my favorite machinist, Eric Johansen (sorry Tom Tobin), I came up with the above design. They are made of 6061 aluminum and slip nicely into the reliefs on the bottom of the XADV-6 boots. A drilled slot in the front engages with the binding pin to keep it from slipping forward or backward.

Thankfully, the designers of the XADV-6 boot included a crampon ledge in the back of the boot. When the shank is installed under the crampon and the heel throw is locked down, the whole boot becomes rigid and the crampon is locked on. It really feels like you're wearing a mountaineering boot!

Since these boots do not accept a wire bale in the front, you're limited to crampons with a rubber toe strap. The Petzl Vasak fits nicely.

Results

Now for the fun part! I took the setup out onto the Augustana glacier (eastern Alaska range) for a 20-mile ski loop with the Alaska Alpine Club (a fine organization, if I do say so myself). The skis are Madshus Glittertinds with SNS-XA manual bindings and kicker skins. (Photo credit Kristen Hendricks)

Our first camp was made below Halcyon peak--just a hill dwarfed by the massive Hayes peaks to the north. After a quick run up (no, not ALL the way to the TOP) on Halcyon, it was clear that these boots climbed quite well. There were never any issues with the crampon coming undone, or even loose. French technique and front-pointing were pretty darn good, with just a tiny bit of slop in the boot. Kicking steps was great.

It is worth noting that, though the boots climbed better than I had expected, the ski setup itself was all wrong for the trip. First off, kicker skins were not enough to keep me moving in the skin track--I kept slipping back. These skis are also not much for downhill shredding. However, when we finally hit the creek, it was ALL worth it--the poling was effortless and the skating was divine.