This is the first and most important thing when sizing or fitting a cross country ski because skis have different stiffnesses. The stiffness of a ski will determine how the ski behaves under the skier.

Longer skis are naturally stiff because of the amount of material used in their construction. So often the skier's weight will dictate the length of the ski, but if given the choice of two lengths the skier's ability should be considered.

Longer skis are generally faster but can be difficult to control or maneuver for beginning skiers.

Touring is a type of classic skiing that is done on or off a groomed trail.  Traditional touring skis have been around for decades and are made with a mechanical climbing aid cut into the ski base (fish scale) or a mohair ‘skin’ to help with ski grip.  They have a length of somewhere between 195 and 210cm long. These skis are generally made with a foam or wood core, a fiberglass top sheet, and affordable polyethylene base material.  Over the last decade a shorter version of touring skis has developed.  These skis are anywhere between 170 to 195cm.  These skis are much wider to help with stability and provide a nimbler experience.  Touring skis are for those skiers who are looking to enjoy the outside in the winter, touring local trails, parks, fields and lakes. 

Backcountry skis are for those looking for a wilderness experience while skiing.  Backcountry skis come in different lengths and styles, but all provide a stable, robust ski that allows skiers to ski off trail and over varying terrain.  Most backcountry skis come with either a full metal edge or a 2/3 metal edge down the length of the ski.  Backcountry skis come with a mechanical climbing aid, a mohair skin, or have a flat base to allowing for an external skin to be attached while climbing.  Most backcountry skis are wide and longto make for a stable experience.  Backcountry skis can often accommodate a wide variety of binding choices, from light touring bindings up to wider backcountry bindings.

Performance classic skis are more race-oriented skis that are much thinner than touring and backcountry skis to allow for more speed in the track.  These skis are used in a groomed track meant exclusively for cross country skiing. Performance classic skis are generally much stiffer underfoot than touring skis to allow for a layer of kick wax or a mohair skin.  A properly fit classic ski is stiff enough to allow the wax or skin to ‘glide’ over the snow, but also allow the user to ‘kick’ the wax or skin to engage the snow crystals for grip. These skis are generally between 180-210cm for adult sizing.A well fit classic ski is necessary for this type of skiing.

Race classic skis are similar in shape and appearance to performance classic skis.  The difference is in the materials used and the shape of the camber.  Race skis are built with the lightest possible materials, have the highest quality base material, and are generally the stiffest cambers of all the classic skis.   These classic skis are built to be as fast as possible, favoring the fastest possible glide over ease of kick, and consider that the user has a strong, athletic kick to get the skis to function. Along with wax able classic skis there are a few special outliers in this category. Zero skis are a type of race classic ski that have a special inlay in the kick zone to be roughed up with sandpaper for tricky wax conditions around zero and above.  Double pole skis are skis with a special camber profile for marathons that have many double pole sections with flat and rolling terrain.  

Skate skis fit shorter than classic skis.  The camber underfoot also needs to be much stiffer than classic skis as it must support the skiers’ weight in suspension throughout the entire push phase.  The camber will never touch the ground.  Performance skate skis are built and designed with stability as the focus.  

Race skate skis are built to be as fast and light as possible.  Most manufacturers achieve this by building a camber profilethat pushes the contact zones of the ski in towards the heel and toe of the skier, this makes for a fast ski, especially when you compare it to a performance skate ski.  The best skis are built with very light and stiff cores and the best polyethylene base material.  Race skate skis can be purchased for different snow conditions with most manufacturers making skis with different camber profiles and base material for cold, warm, soft track, hard track, or wet conditions.