Ski boots were originally made of leather and resembled standard boots. As skiing became more specialized as a form of recreation, so too did ski boots. Currently, most ski boots fall into the categories of Alpine skiing, Nordic or Randoneé/Alpine Touring. These varying disciplines each use a specialized type of ski bindings and as such, are generally not interchangeable.
Boots intended for downhill use (Alpine, Randoneé, and Telemark) are generally composed of a hard plastic shell with a softer foam liner to provide warmth and comfort. Concerning liners, a thick soft liner will be more comfortable and provide more insulation while thinner, harder liners provide more precision. Comfort has been improved in recent years by the use of conformable linings (usually heated to fit) which allow an otherwise stiff liner to be molded to the foot and comfortably accept a large variety of foot shapes.
Shells come in various degrees of stiffness; beginners typically like a softer and more padded boot, while more advanced skiers generally prefer a stiffer boot with a thinner liner. Softer boots are able to be flexed with less pressure applied to the cuff making them a good choice for lighter or less aggressive skiers and translates into a more forgiving ride. This quality is also desirable when efficiency and comfort during touring is a concern. Softer boots are often lighter as well due to thinner shell material; a desirable quality when touring as well. Increased boot stiffness generally translates into more precise energy transmission from the skier to the ski. It also provides better support for increased g-loading during high-speed turns, and heavier skiers. Stiff boots however are often less comfortable and heavier than their softer counterparts.
- Boots which are too soft for a skier will not feel sufficiently responsive, and will over flex during high-performance skiing.
- Boots that are too stiff for a skier will transmit unintended control movements to the skis, and will not flex sufficiently in varying terrain or during normal intensity skiing.
Alpine
Alpine Ski Boots have rigid soles and attach to the binding at both toe and heel using ISO DIN standard bindings. Because of the bindings, they forego rubber soles in favor of hard plastic for better safety and precision. There are three basic types of ski boots which vary in the way the ski boots close around the lower leg: rear-entry, front-entry, and mid-entry ski boots.
"Front-entry" boots are the primary boot of choice for performance-oriented skiers. The high, rigid cuff provides excellent power and control transfer from the skier to the binding. Buckles across the shin, instep and forefoot provide much adjustability and control in fit, and due to the rigid cuff, lateral boot stiffness is generally very good. Forward-flex is varied depending upon intended use, but ranges from easily flexed beginner/intermediate boots to extremely stiff boots intended only for racing.
Rear-entry Ski Boots
This is the simplest and cheapest type of ski boots and is good for beginners. They offer ease in entry and exit by unbuckling an independent hinged cuff at the rear of the ski boot. This type of boot however does not adjust to fit across the front of the foot, often resulting in a poor fit and considerable "slop" in the forefoot area. These boots were very popular until the late 1990s due to their economy and ease of use. Recent improvements to Front-entry and mid-entry boots, primarily in the areas of comfort and ease of entry/exit, have diminished their popularity, though they remain very common as rental boots.
Mid-entry Ski Boots
These combine many of the strengths of both rear-entry and front-entry ski boots. While still adjusting via buckles across the forefoot and shin, the rear cuff of the boot is allowed to hinge back slightly to allow for a larger opening and thus an easier entry to the boot. In this way it provides the convenience of wearing rear-entry ski boots, while at the same time offering much of the performance and versatility of front-entry ski boots. Mid-entry ski boots are recognizable by a wide-opening cuff which opens to the front and to the back.
Shell-fittings
A shell-fit is when the the technician removes the boot liner and has the customer place their foot in the shell and slide it foward until the toes begin to touch. Then the technician will slide his hand down the back and see how much room is behind the heel. You want between 1 to 2 figures to fit. This is the best way to determine if the boot is the right length for you.
Shell modification
When the boot is physically stretched to allow for specific feet.
Nordic
Cross Country
Cross country boots, like all Nordic equipment, attach to the ski only at the toe of the boot and are allowed to flex at the ball of the foot similarly to a normal shoe or boot. Cross Country boots generally use one of three attachment systems; NNN (New Nordic Norm), 75mm Nordic Norm ("three-pin" binding), or SNS (Salomon Nordic System). As these boots are intended for travel over generally flat terrain, they are optimized for light weight and efficiency of motion.
Telemark
Telemark refers to a specific technique for making downhill turns on Nordic equipment. This has resulted in highly specialized equipment designed for better performance in a downhill setting. Until 1992 Telemark boots were basically heavy leather boots with the front of the sole adapted to the 75mm Nordic Norm. Since then plastic boots have become more and more common and now make up almost all Telemark boots. Plastic allows for a laterally stiffer boot while still allowing freedom of flex at the ball of the foot through the use of bellows. Boots intended for more cross country travel generally have a lower cuff, softer flex and lighter weight. Boots specialized for downhill use have higher cuffs, stiffer flex and heavier weight. Telemark boots are almost always equipped with a rubber sole.
Randonée (Alpine Touring)
Alpine Touring boots are intended to allow cross-country travel while also being configured for downhill skiing using Alpine technique. Due to this they are a compromise between performance and light weight. Unlike Alpine and telemark boots which have standardized binding attachments, Randoneé boots are often specific to the type of binding being used. Boots designed for Fritchi, Silvretta and Naxo bindings use a toe and heel attachment very similar to Alpine Boots as Alpine boots may be used in these bindings (Alpine touring boots should not be used in Alpine bindings however). In the case of Silvretta bindings, plastic mountaineering boots are permissible for use. Boots designed for Dynafit bindings attach via two indentations on the sides of the toe of the boot, foregoing the hinged plate used by other AT bindings and instead pivoting and locking only to the boot itself. Alpine Touring Boots usually have rubber soles.
