ACS News Service Weekly PressPac: May 11, 2016

How to make a faster ski

"Effect of Different Bearing Ratios on the Friction between Ultrahigh Molecular Weight Polyethylene Ski Bases and Snow"
ACS Applied Materials & Interfaces

Although ski season is behind us, serious skiers are already looking ahead to next season and searching for ways to shave split-seconds off their race times. Now scientists may have a new way to help — perhaps in time for the next Winter Olympics. One team has determined how the microscopic texture of the bottoms of skis could affect their speed, depending on snow temperature. Their study appears in the journal ACS Applied Materials & Interfaces.

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.

The authors acknowledge funding from the project “K-Regio: Skitechnologie” of Tyrol, Austria.

Skis made with the right microscopic texture on the bottom can shave time off a race.
Credit: rcaucino/iStock/Thinkstock