Tech Trend: Compact Aero Helmets

Don’t trust your eyes: A helmet with a short tail may be your best bet for speed.

Relying on intuition is a terrible way to gauge aerodynamic performance. The teardrop-shaped airfoils that were widely used on tri bikes during the previous decade look fast. They’re sharp, long and have a vague resemblance to the shape of a jet fighter. But they aren’t actually as aerodynamic as some fat, blunted tube shapes. Fast helmets often fail the eye test as well.

A helmet with a long pointy tail that sits flat against a rider’s back looks fast, but it doesn’t always achieve the same level of success in the wind tunnel. Olympic-distance specialist Cameron Dye went to the San Diego Low Speed Wind Tunnel in 2012 to experiment with his position, apparel and helmet options. His sponsor Rudy Project made a short-tail helmet that left a gaping space to Dye’s back. He tried two other long-tail options from other brands that filled the space and looked faster. Data from the wind tunnel said otherwise—the Rudy Project Wingspan was actually significantly more efficient. Combine the fact that aero performance is nearly impossible to judge with a glance with the realities of a triathlon, and it becomes obvious why stubby aero helmets are exploding in popularity.

Sitting perfectly still with eyes up the road is nearly impossible in a triathlon of any distance. Glance down to grab a water bottle and the helmet tail juts into the air, which can potentially create extra aero drag. And with a run waiting after dismounting the bike, ventilation is important during warm-weather races. Because of all these reasons, it’s no surprise that Specialized, Giro, Lazer, Ekoi, Rudy Project and more have designed their newest aero helmets without a long pointy tail. Athletes in Kona embraced the trend in 2013. From Frederik Van Lierde and Pete Jacobs to Craig Alexander and Leanda Cave, many of the best in Ironman Hawaii selected a lid that combines aero design and ample ventilation.

RELATED: Giro Air Attack Shield Helmet Review