How to Size an Alpine Touring Ski
Touring ski's look and ski like an alpine option, only much lighter.
Touring skis have been evolving at a breakneck speed for the past decade with science and carbon being thrown in at every step in the process. These sleek new sticks have made ski touring easier from edging on hard pack, to floating in powder and of course flying up the skin track. It's true they have made everything easier except for choosing the right one.
If you have read our article How to choose a ski touring setup you already have some insight into which quiver slot you would like to fill. Once you have chosen your ski, the next step is figuring out the appropriate length. There are many different factors that go into making this decision such as, skier height and weight, intended use, ski geometry and, of course, skier preference. This is not an objective process and this article is to serve as a guide for choosing the right length ski for you. Of course if you have any questions you can always email us at info@cripplecreekbc, make an appointment to come see us in person, or leave us a question in the comment section.
Skier Height and Weight
In general, we advise our customers to size their alpine touring skis a bit shorter than a normal alpine ski. This helps reduce overall weight and makes kick turns much easier to get around. However, you don't want to size down too much because your weight and the lever arm of your tibia (a factor of your height) will overpower your ski. While not accounting for certain quiver slots the recommended range for your ski would be from your lips to the top of your head.
Skier Height in Feet & Inches
|Suggested Ski Length Range (cm)|
|6'2" +||175-190 +|
If you weigh a little more for your height, ski very fast wide open turns, or intend on skiing with a heavy pack- then we would suggest sizing to the upper end of your range. Read on to see more factors that will play a roll in deciding the appropriate length ski.
Quiver Slots and Intended Use
One of the important factors for sizing an alpine touring ski is the quiver slot you choose. Powder skis are going to be sized differently to ski-mountaineering tools which will be sized differently to your daily driver. In this section we briefly touch on how a quiver slot relates to length but, again, check out our full quiver slot explanation here.
Choosing the right quiver slot is key to maximizing your fun in the mountains
1) Race and Fitness
If you are looking for a pure race ski your job just got easier. Almost all race skis come in just 2 lengths, one for men and one for women. According to ISMF (International Ski Mountaineering Federation) standards male racers must ski on planks at least 160 cm in length, while women's skis must be at least 150 cm. These options are really short and I know many of the top women that are 5'8" or taller that choose a 160 cm, but if you are looking to be as light and fast as possible- then this is the way to go.
If you are on the fitness end of this spectrum, meaning you race for fun or only against your friends before work, don't be afraid to go a bit longer. You still want to be short, light and maneuverable but it is ok to sacrifice a little bit of weight and efficiency for the sake of downhill performance. As soon as you step up to a ski width in the mid 70mm or bigger there will be plenty of choices.
Thinking about entering a SKIMO Race? Check out the Grand Traverse Packing List to get an idea of what's required.
To maximize speed and efficiency, a race style touring ski is a must
2) Ski Mountaineering
Designed to be weapons in the mountains and on technical terrain; ski mountaineering skis should be sized on the shorter end of the range. They need to be good at sneaking through tight couloirs and carried on your pack while climbing. Also most skis in this category have relatively straight tails which means they have a long effective edge and therefore are going to ski every bit as long as advertised.
3) All Mountain
From low angled powder to light spring mountaineering to resort skinning, all mountain touring skis walk the line between many different categories so it is good to size in the middle of the range.
4) Powder and Freeride Touring
In the Powder and Freeride quiver slot, size does matter. For landing or skiing fast in powder, extra length will keep you floating on top on those deep days when your friends are sinking. If you are on the freeride end of this spectrum, a longer ski minimizes chatter and maximizes stability at high speeds and gives even a light ski the mass to slam through crud.
Longer skis help keep you afloat on deeper days
It is more and more common that new skiers are coming into the sport of ski touring. If you are new to the game definitely down size to the bottom of the range, the skis will be more playful and easier to initiate turns at a slower speeds.
Even if are on your way up to being an expert skier, the stability of modern touring skis has allowed skiers to stay shorter than the norm from 5-10 years ago. You no longer need to bend a 190 ski to have the power to arc a turn. Just lay em over! A longer ski will mean better float in the powder and less chance of being overpowered at higher speeds, so depending on the intended use below you may be able to size up.
Ski Geometry: Rocker, Camber, Side Cut and Tails
Back in the day skis were skinny and straight and usually really, really long. Today there are a number of factors in the overall shape of the ski that determine the length of ski you should be in.
1) Rocker and Camber
There is no escape from acknowledging that rocker has and will be an essential part of ski shape moving forward. Although we have seen "full rocker" skis drift out of fashion at times, tip rocker remains standard across all ski types and manufacturers. Tip rocker refers to the tips of the ski coming off the snow closer to the middle of the ski. This helps with turn initiation and floatation in soft snow. and skiers can now drive a rockered ski in a forward stance and not have the tips hook or dive. Tail rocker works on the same principle offering ease in turn initiation and release at the end of your turn. Rockered skis pivot more easily and usually are skied from a more centered position. The more rocker a ski has, the less edge is in contact with the ground, meaning the ski will feel shorter in firmer conditions.
Camber refers to the arc underneath your ski when you lay your skis flat on the snow. When the ski is weighted with a skier, the arc disappears distributing energy along the length of the ski. A ski's "pop" is generated by the loading, or flattening, of this camber through a turn and then the energy of it returning to its shape when you begin to unweight it. As a result, a cambered ski will also be a more powerful ski, both requiring and rewarding energy in the turn.
Most touring skis have a combination of tip rocker and camber underfoot. A select few are still made traditionally with only camber. The most progressive skis have massive tail rocker or will be fully rockered. But what does this mean for skiing?
It is widely accepted that rocker will cause a ski to ski much shorter, pointing to the 2 contact points being much shorter than overall length. This however only applies to skiing on hardpack and is generally a hand-me-down bit of advice from the alpine world where even powder days involve a healthy amount of groomer skiing. In deep snow (the point of a heavily rockered skis) the entire length of the ski is in play. The rocker is then helping to prevent tip dive and making pivoty-slashing turns more fun. Even in less than deep conditions, a rockered ski utilizes more than it's flat ground contact points as you lay it over throughout the turn. In fact, in the snowboard world, rocker allows snowboarders to ride even shorter more nimble boards because of the flotation and turn initiation advantage. The take away here is that it's safe to choose a longer pair of skis if it is has more rocker, but no need to size up.
2) Sidecut or Turning Radius
Turning radius and sidecut should be considered, but don't get hung up here. The sidecut refers to the ratio between tip, waist, and tail width. The bigger variance between tip/tail width and waist width, the tighter the turning radius. When the ski is bent in a turn, the arc that the edge creates is extrapolated into an imaginary circle. The radius of that circle is the turn radius.
Ok knowing the "science" behind turning radius and sidecut is not crucial to your skiing, but it is important to know that it is only a suggestion. This is also another holdover from the alpine world. There are very few occasions in the backcountry where a ski is fully railed on arcs. Skis with more sidecut or a smaller turning radius will in general feel "turnier" but that doesn't mean a fat ski with little sidecut can't be whipped around when you need to be quick. Don't let sidecut alter the length choice of a ski. Start with your skiing style, choose a ski, and then base length on the other factors described. This generally ends up with smaller turn radius for shorter skis, and vice versa.
Skier Preference and Terrain Choice
Even within quiver slots, let your preference of where you ski or how you ski be the guide. Within the powder category a skier living in Alaska is going to have wide open bowls to find the goods and arc big turns on a longer ski, while a skier in Vermont is going to have to dig deeper and make tighter turns into tighter trees for the freshness where a shorter ski will often be more enjoyable. Or maybe you like to milk wide open bowls for hundreds of turns. Ask yourself, what terrain will I find myself most likely in and let your answer be your guide.
High altitude ski missions require a nimble mountaineering tool
What boot will you drive the skis with?
This comes in to play when blending boots from a different quiver slot than the ski. One common example of this is using a race or ski mountaineering boot for more of an all mountain approach to skiing. No matter how proficient the skier, a slightly shorter and narrower ski will be the right match for a light weight boot. Conversely, if you prefer a stiff alpine-esque freeride boot, you will start to loose the feel of a ski in the shorter end of the range.
In summary, longer skis are for experienced skiers and those that ski at a higher speed, in wide open terrain, or with a big boot. Shorter skis are for newer skiers, technical terrain choices, light boot pairing, or those who make tighter turns. Don't hesitate to shoot us an email or call us up where you will always talk to a real person who has made this decision many times for their own skis!
View our complete intro to ski touring guide here.
- Thomas Bull