How to make a faster ski

For many recreational skiers, rental equipment from a resort shop suffices. But for more serious athletes, a lot more consideration goes into equipment choice, down to how a set of skis is fabricated. The bottoms of skis are made of a material called ultrahigh molecular weight polyethylene. Manufacturers stone-grind the polyethylene, which roughens it. Some studies have investigated how texture on the undersides of skis affects performance. Sebastian Rohm and colleagues wanted to build on this work.

The researchers measured the shapes and sizes of the microscopic grooves that give the polyethylene its roughness and analyzed how these variables affect ski speed at different snow temperatures. Testing showed that on snow close to water's melting point, a ski surface with wide grooves and narrow plateaus between them performed faster than a surface with narrow grooves and wide plateaus. The opposite was true on colder snow. The researchers say their results could lead to improvements in how ski surfaces are prepared and used in a variety of snow conditions.