An Ultimate Guide on Choosing Skis
There are many types of skis out there suited to different types of skiing, and to understand why, first we need to have a basic understanding of how a ski works. There is a lot more to a ski than a lot of people realise, and things you might not have noticed can make a large difference to how a ski performs.
Below are explanations on what each part and property of a ski does, along with how all of these parts and properties can come together to make skis suited to different types or styles of skiing.
The base is the area on the bottom of the ski that comes into contact with the snow. Generally when looking to buy skis the base will not be something you consider much, although it is still a very important part of a ski.
To make a ski base slide nicely on snow and to keep it in good condition, a special wax is applied to the base. The wax is normally applied by melting the wax into the base with a hot waxing iron, although there are less effective waxes that can be applied cold. Keeping a base well waxed is the most important thing to keep the ski base fast and in good condition. There are many different types of wax that can be used, usually suited to different temperatures of snow, although some also have different additives in them. These are covered in more detail in the Ski Construction page.
Ski bases are made of P-Tex, a polyethylene plastic, and can vary in many different ways. There are different qualities of P-Tex, extruded and sintered constructions, and different additives that can be used. This makes different types of bases have different properties, which can make them faster, stronger or able to hold more wax than other types. The different types of bases and their properties are covered in more detail in the Ski Construction page. Quickly summed up, sintered bases are superior to extruded bases as they are more durable, faster and hold wax better, but at the same time are more expensive and more difficult to repair. The best types of bases are sintered hybrids that have graphite and other materials in them, they hold wax even better and are even faster. They are always a dark black colour, and are most commonly found on racing orientated skis.
The base of a ski can get scratched if the ski goes over hard objects such as stones. For general skiing as long the ski is kept well waxed, the amount of scratches on the bottom will not make much difference. Although if you do have large scratches, it is best if they are down the length of the ski, and are not too close to the edges.
When a ski has been well used and has collected some scratches on the base, it is common to get the base of the ski ground (sanded down on a machine) as part of a ski service. This takes a layer off of the base and the bottom of the edges, to make the base and edges smoother again. When a base is ground it will be left with slight grooves running along the length of the ski. Depending on how deep and far apart these grooves are, it makes the ski better for different snow conditions. Generally the deeper and further apart the grooves are, the better it will be in wetter snow. Most skiers however use their skis in all conditions, and are fairly unaware of the differences base structures can make.
The edges are the metal strips that run down the sides of a ski. Edges are very important, and can make a big difference to the performance of a ski. There are many things that effect the edges and how they work, like sidecut radius, edge angle, sharpness and stiffness (stiffness is explained in it's own section). Lets look at the sidecut radius firstly.
If you look at a ski you will see that it is wider at the tip and tail than it is in the middle. This is because the edges have been shaped so that they curve along the sides of the ski. If the ski is tilted onto an edge, this curve will try and lead the ski around in a circular path. The curve shape on the edge of the ski is called the sidecut, and will have a sidecut radius which is determined by the effective radius that the curve has. The radius of the sidecut (or R) is normally written on the top of the ski somewhere with a measurement in metres. A ski with a smaller sidecut radius will make smaller tighter turns when the ski is being carved, whereas a ski with a larger sidecut radius will make larger turns. The radii on skis can vary largely, and are normally suited to the style of ski. The sidecut radius is not the radius that a turn will be when the ski is carved however, and is in fact closer to being the maximum radius a carved turn can be. The more a ski is leant over the smaller the radius of the edge touching the snow will become, and generally speaking the smaller a carve turn will become.