Ski

This article concerns the skis used in skiing. For the town in Norway, see Ski, Norway.

A ski is a thin, flat-bottomed device attached by means of bindingss to the skier's ski boots, with a slightly upturned, pointed front end to avoid digging into the snow. Also, a ski may denote a similar device used for other purposes than skiing, e.g., for steering snowmobiles.

Construction

Skis were originally wooden planks. They are now usually made from a complex assembly of components including glass fiber Kevlar or related composite materials, though they may contain a wood core.

In alpine and backcountry varieties of skiing, and sometimes in others, skis have strips of metal running along the lower edges of the ski to bite into the snow more effectively.

Shape

The sides of most skis describe a parabola, making the ski narrower under the skiers foot than at the tip and tail. By setting the ski at an angle so that the edge cuts into the snow, the ski will follow the parabloa and hence turn the skier, a practice known as carving a turn. Faced by competition from snowboarding, during the 1990s this shaping of the ski became significantly more pronounced to make it easier for skiers to carve turns, and such skis may be termed carving skis. For other turning techniques, see Skiing.

Types

Many types of skis exist, all designed for use different situations, of which the following are a selection.

Downhill ski

Downhill skiss are svaged to promote easy turning. The ski binding anchors the foot firmly to the ski at heel and toe. It is spring-loaded, detaching the ski from the foot in case excessive force is applied.

Alpine ski touring ski

Alpine ski touring ski. This type of ski is ususally a light-weight downhill ski with a alpine touring binding.

Telemark ski

Telemark ski. A downhill or touring ski, where the binding attaches only at the toe. The Telemark ski was the first ski with an inwards-turned waist which made it much easier for skiers to turn. It was pioneered by Sondre Norheim of Telemark, Norway

Cross-country ski

Cross-country skiss are very light and narrow, and usually have quite straight edges. The bindings attach at the toes only. They are usually coated with wax to reduce friction during forward motion, but also to get adhesion when going uphill. Some models may have patterns on the bottom to increase the friction when the ski slides backward. These skis are also used in biathlons.

Backcountry ski

Skis for mountain/backcountry/cross-country free range skiing which are designed for skiing on unbroken snow, where an established track is lacking. These are characteristically quite wide, and with cable bindingss to provide general sturdyness, and to better extract ones feet from deep snowbanks, in case it should be impossible to reach the bindings by hand. This is also the model used by military forces trained to fight in winter conditions, and the most closely related to the historical ski.

Ski jumping ski

Skis for ski jumping. Long and wide skis, which bindings attaching at the toe.