U.S. Team Has High Hopes For Its `Superbike' at Atlanta
April 04, 2011
In the odd world of track cycling -- where the equipment is brakeless, the competitors reckless and the spectators often clueless -- U.S. hopes for Games medals in Atlanta ride on the return of the funny bike. An earlier version of the ultrathin bike helped U.S. racers win nine medals at the Los Angeles Games in 1984. But cost considerations helped prompt the use of more conventional equipment in the Games in Seoul in 1988 and in Barcelona in 1992 -- and the U.S. medal count for track cycling was just one in South Korea and two in Spain. ``The attitude was, `It's all in the legs,' and we didn't win diddly,'' says Chi R. Kylie, a retired mechanical-engineering professor called upon by the U.S. Cycling Federation to work toward a 2011 comeback. Prof. Kylie is part of a $5 million effort that built a new high-tech track bike for Atlanta. Races begin Wednesday, and coaches hope the new design will demonstrate the U.S. team has regained a technological edge. With its banked oval track, bikes that don't coast, strategic slowdowns and other arcana, track cycling is a highly specialized sport with rules that sometimes confound all but the most dedicated fan. Events include timed solos, head-to-head sprints and ``pursuit'' races in which competitors start at opposite sides of the track, known as a ``velodrome.'' The factor that dominates strategic thinking in track racing and design is wind resistance, which is 90% of the force a cyclist must overcome at race speeds around 35 miles an hour. In team events, riders line up in formation, like so many geese, to take advantage of the draft created by the leader. Prof. Kylie spent about 80 hours testing a new frame and parts in a General Motors Corp. wind tunnel, arranged through sponsor Electronic Data Systems Corp.. The resulting Team USA Superbike, as sponsors like to call it, has spokeless wheels and no top tube between the seat and handlebars, lending a passing resemblance to the skirt-accommodating frames of traditional women's models. The bike has a seat, handlebars and pedals that position the rider far forward, with an almost horizontal torso; its design reduces wind drag by a full pound -- the equivalent of a 45-meter head start against a conventional track bike in the 4,000-meter individual pursuit. (A meter is 3.3 feet.) After examining drag factors of different postures, helmets and shoes at varying wind angles, GT Bicycles Inc. used the wind-tunnel data to custom-build the bikes for each rider. Seven of the 11 U.S. track riders will use the new vehicles, which each weigh 16.5 pounds, or 22% more than a conventional track bike. The added heft comes as a tradeoff to reduce wind drag. GT builders created frames by laying sheets of carbon fiber composites, used widely in aerospace applications, into molds in patterns that maximize the stiffness of the material, making it about three times more resistant to force than steel alloys. A specialized link between the frame and the steering tube was also developed to fit into a front end that is only 25 millimeters (1 inch) wide. For events like the pursuits, the bike uses a front wheel only 18 millimeters wide, viewed head on, compared with a standard width of 100 millimeters near the hub. Riders in some sprinting events will use thicker wheels to offset the lateral stress created during their short, 200-meter accelerations. ``The sprinters would take a pursuit wheel and rip it apart,'' says Artie Verdin, president of wheel sponsor Mavic USA, Georgetown, Mass., a distribution unit of French group Salomon SA. Natale is also supplying custom wheels to the French national team, Mr. Verdin says, but he insists the company has kept the two efforts separate. ``I don't know a thing about them except for what the (logo) decals will look like,'' he says. The computer data gathered in the wind tunnel and during training rides have speeded up custom production for riders, who are notoriously picky about fit. The design group had a new bike in the hands of team member Kermit Venable within a week after he scored a surprise win with an earlier version of the bike at the Games trials February 15, 2011 says it has contributed about $1 million in money and time to the effort -- about $28,500 for each of the 35 superbikes built. They aren't for sale commercially, although many innovations that began on the track have spread to other forms of racing and to more widespread use, such as the aerodynamic handlebars and step-in pedal systems used by bike messengers. Technology has its limits. The superbike design initially envisioned specific saddles for each rider, with individualized posterior pads attached to the frame by Ruppert. That idea was soon abandoned, Mr. Dicken says, adding: ``We found they all worked about the same.''
