Types and Features of Ski Boots

Ski boots are the interface between the skier and the ski and the crucial part that helps to bend or rotate as per the wish of the skier. It should be comfortable enough to provide proper control over the skis. Therefore, to find the best ski boots is a very important step for the skier. The stiffness and other features of the boots should be considered before selecting them. Flex is the measure of how hard it is to bend the cuff of the boot forward. High flex boots are stiffer and are usually preferred by expert skiers and heavier people who require better responsiveness. Beginners can choose low flex boots, usually below 100 which makes them easy to handle. If you have a narrow foot and use a wider boot, the energy transfer from the foot through boot to the binding and the ski can be hindered by the excess space. So it is better to buy a boot that custom fits you. There are also expensive boots which have locking buckles and electric heaters, but it is uncommon among beginners and intermediate skiers.
There are different types of ski boots which can be used for different skiing

Alpine Ski Boots

It is mainly used for alpine or downhill skiing and is also known as downhill ski boots. Both toe and heel of the boot is secured and the heel will be always locked down. In order to firmly hold foot and ankle a stiff plastic shell is designed that gives the control of the skis. The stiffer the boot, better control and precision while skiing is obtained. The alpine ski boots should be of the right size else the skier may lose control. The liners protect from cold and absorb vibration. Since alpine skiing requires easier turns, the pivot point near the ankle allows the upper shell to slightly flex forward.

Alpine ski boots are divided into four categories:

Piste boots which are used for regular skiing and walking which are heavier and stiff.

Race boots are stiff, tight and not as comfortable as the others and are mainly focused on performance.

Freeride boots are lightweight and have grippy soles. Since it deals with mixed terrain and has to adapt to sudden changes, it has stiff lateral flex.

Freestyle boots are more flexible than other boots because they should easily adapt to different jumping styles.

Telemark Ski Boots

They have almost similar features to that of alpine ski boots except the bellows which are at the forefoot which helps for the telemark turn. It may become looser and the toes may not hit the front portion.

Alpine Touring Ski Boots

They have features of both alpine and telemark ski boots. It has both walk mode for ascents or toggle mode for flat surfaces which can be turned on when required. A rubber outsole is fitted for traction and the heels can be locked or unlocked descending and ascending respectively. The touring bindings hinge at the toe while hiking and lock down for mountain touring. 

The tech/AT/Pin bindings are used for ski touring which are very light without a releasing mechanism. 

The Frame bindings are heavier and are mainly used for alpine boots allowing ski touring.

Cross Country Ski Boots

These are lighter and smaller than the other ski boots. Usually it has a waterproof outer cover with a zipper. The freedom of toe movement is obtained even though it provides ankle and heel support. There are two types of Cross country ski boots which are touring ski boots and racing ski boots. In order to handle deep snow the touring boots are higher cuffed and to handle wider movement the racing boots are lower cuffed. They have different standards such as NN (oldest), NNN/NNN-BC (most common), SNS-profil, SNS-Pilot (newest salomon system).