Parabolic Skis vs Straight Skis

When, in the early 1990s, alpine skis started showing up at retail shops looking a bit more like snowboards and less like traditional, straight-edged skis, customers had their curiosity piqued: what was the advantage of this new shape, and why bother to upgrade? The fact that almost 20 years later ’shaped’ skis are the only type of ski being manufactured and sold is testament to the answer: they work. That is: shaped, or parabolic, skis ski well and with remarkably less effort than those traditionally designed.

Borrowing from the shape and design of snowboards, which do not have a straight edge, but rather an arched one, ski designers and manufacturers began experimenting on alpine skis in form and function.

The traditional straight-edged ski was maneuvered by applying a great deal of force to the ski, pressuring the ski into a flex or arc, called reverse camber. Straight-edged skis were to designed to use a combination of pressure and rotation to ’set’ the metal edge on the ski and thus create or carve a turn. This method of turning the skis required leg strength and stamina that, often, younger children or older adults found challenging.

By contrast, a shaped ski – wider at the tip and tail than at the middle or ‘waist’ of the ski – is created with what is a called a ’sidecut’. This sidecut, when engaged by the skier by moving weight to his/her metal edges, does exactly what rotating and pressuring the ski does on a traditional model, it carries the ski through the turn. The result is ease of turn initiation and follow through and a more fluid ride.

These benefits appealed particularly to those who were frustrated with the physical demands of turning a straight alpine ski but also to those who wanted to carve turns more efficiently and with less stress on knees, ankles, and back.

Over time, the types and variations on sidecut have changed as more specificity of use has crept into the ski industry. The length and depth of sidecut will determine the turning radius of a ski (together with the variables of stiffness and ski length), thus the greater the difference between the width of the tip and tail as compared to the waist of the ski, the deeper the sidecut, the shorter the turning radius, and conversely, the shallower the sidecut the wider the turning radius.

Slalom and recreational skis tend to have deeper sidecuts, as their application is typically making tight, short turns that require the least amount of effort. Powder and ‘downhill’ skis tend to have shallower sidecuts which allow for more speed and the ability to make larger ‘S’ turns in deep snow.

The introduction of the shaped or parabolic ski was truly revolutionary in the ski industry. Not only did it mean that skiing became easier – less difficult to learn and less taxing on the body, it meant that skis could be crafted to fit specific niches of the alpine market: carving, all-mountain, big mountain, and powder. This was a boon for an industry that needed both longevity in its participants and the ability to convince newcomers that the sport was enjoyable to learn.