Big Island Innovation

Published October 4, 2012 03:52PM

Straight from the engineering lab to the Queen K, these five trends are making Kona’s fastest athletes look more and more like they’re racing Olympic distance.

Kona is the last refuge of standard road helmets in the pro triathlon field. Still, countless wind tunnel tests have inarguably shown that aero helmets make a cyclist faster (most tests show a time savings of 3 to 5 minutes in an Ironman), and successful races in Kona—by athletes big and small—have demonstrated controlling core temp is still possible while riding with an aero helmet.

Every one of the top 15 male finishers in 2011 raced in an aero helmet. Many of the women, however, still favor road helmets. Of the favorites in 2012—Carfrae, Joyce, Cave and Steffen—only Carfrae, the weakest rider of the bunch, opted for the aero helmet last year.

Despite redlining in the heat for four-plus hours, most pros are streamlining the supplies they carry on their bikes. They rely on aid stations and/or special needs to regularly refill rather than schlepping everything for 112 miles straight out of T1. And carriers either behind the saddle or between the arms are replacing standard frame bottle mounts. Of the top 10 finishers in 2011, only Faris Al-Sultan (the guy who races in a swim brief) brought two bottles on his frame. Placing a bottle horizontally between the arms using either a mount from X-Lab, Profile Design or simple zip-ties is the current fashion because, according to Specialized aerodynamicist Mark Cote, this bottle placement actually reduces aerodynamic drag by “filling the void” between the arms. A bottle on the frame can cost between “one-tenth and a one-quarter mile per hour of speed,” says Cote.

Until recently, aero wheels have been judged only by the wind resistance they create. If a wheel spits out low drag numbers from a wind tunnel test, it must be fast, right? While these numbers truly are important, they aren’t the only factor. Stability, especially in the violently unpredictable crosswinds of Hawaii, also impacts how quickly an athlete arrives at T2.

When Zipp began testing prototype rim shapes that would eventually become its current Firecrest wheels, engineer Michael Hall and technical director Josh Poertner came across a phenomenon that explains the shaky feeling of riding deep wheels in the wind. Crossing air doesn’t stream smoothly over the wheels; it builds up and releases in bursts. When a pocket of air separates from the rim—Poertner calls this “vortex shedding”—it forces the wheel to twitch slightly, creating unstable handling.

To solve this problem, Zipp blunted the inner edge of its deep wheels instead of using a typical pointed shape. This new design prevents air from clustering on the rim and releases it in very small, frequent bursts that don’t influence handling as dramatically as wheels from the previous decade. Enve, Hed, Rolf Prima, Bontrager, Shimano and others have adopted similar designs, and the difference on the road is astounding.

Most of the contenders now ride aero wheels created to subdue crosswinds, but there are a few exceptions. Athletes riding rims that predate this technological evolution will be at a substantial disadvantage while trying to control their bikes through strong gusts.

The rulebook governing the pro race says athletes must space themselves during the bike by at least 10 meters. In Kona, however, WTC enforces a more strict policy (full explanation coming next week). They also have to move to the side of the rider in front to pass. These rules are in place to prevent drafting and, for the most part, they are successful. But a large pack of cyclists—especially in the men’s race—clusters during the first half of the ride. This group, 19 strong in 2011, provides both mental and physical relief for the athletes who make the cut.

We re-created legal pack riding conditions and measured the watts required to keep pace with the fastest men riding alone and with the shelter of a group. The results are compelling: Riding at a legal distance saved our test subject 12 watts, enough power to cut approximately 4:30 over 112 miles.

Normann Stadler swam with the lead pack for the first and last time in his career en route to winning the 2006 championship. He was wearing a buoyant swim skin produced by Blueseventy, and no other athlete had one. But the days of suit technology swinging the world title are gone—for now. Current regulations prevent the use of buoyant neoprene and hydrodynamic shaping or coatings that have the potential to make one suit dramatically faster than another. Current-generation swim skins are still effective and completely necessary to keep up with the competition—our own tests found them to be worth between 1 and 1.5 seconds per 100m over a swim brief. The fact that every pro now wears one in Kona puts them all on a more even playing field than in years past when manufacturers had to scramble to create legal suits in time for the race.