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Once every four years, the vast majority of people realise track bicycles are something other than "those fixed-gear things hipsters ride." The features that make these bikes so inefficient in all but the flattest, smoothest situations also make them so fast on the wooden track of the Olympic velodrome.
Well, that and the riders.
While the Olympic road race isn't all that different from a stage of the Tour de France, track cycling is less familiar because the sport doesn't have a strong following</a> in the United States, notes Benjamin Sharp, endurance high performance director for USA Cycling. And like many sports that get attention only in Olympic years, track bikes are some of the most advanced sporting goods you'll find.
Track cycling includes 17 events, according to cycling's governing body, the UCI. Five events – the same five for men and women – appear in Olympic competition. Races fall into two broad categories: sprint and endurance. The bikes resemble stripped-down road bikes and time-trial bikes, but each has features that make them utterly unique.
For one, they have no brakes. It's the Olympics; if the riders wanted to slow down, they wouldn't be there. Because of the consistent shape and smooth surface of the track and the types of races ridden on it, brakes aren't necessary. It's actually safer without them, Sharp says. "It's not essential," he says. "There's no reason to have to come to a quick stop in a velodrome."
Without brakes the riders can't vary their speed as much, so a drafting rider will never have to slam on his brakes in response to a variation from whoever is leading him.
And although all track bikes have just a single fixed gear (no coasting), their gear ratios differ based on the event. A sprinter, for example, will run a lower ratio than an endurance rider; they have to accelerate quickly, whereas in the longer distance races, riders want to cruise at high speed.
That's not the only difference between sprint and endurance. As with many road bikes, track bikes have to deal with a tradeoff: weight versus stiffness. Because of the power sprinters pour through their frames, the carbon fibre used to craft them tends to be thicker, and heavier, than you'd find in road bikes. The designers are still cutting weight everywhere they can, reinforcing critical junctions like the bottom bracket.
The bikes are of carbon fibre, of course. Jamie Staff, director of sprint for USA Cycling and a 2008 Olympic champion in team sprint, points to the introduction of the material as a big technological advance in a sport where big investments tend to bring tiny rewards.
Because the races are contained, the wood track is smooth, and it's always an oval, races are "very predictable," says Staff. By that, he means that, without confounding factors like weather or obstacles, a racer's times don't vary much. And that means small advances in tech throughout the bike can make a noticeable difference in the rider's performance.
All those advances, though, are held within tightly-controlled constraints handed down by the UCI. The Union Cycliste Internationale's ten-page guidebook to bike regulations</a> includes acceptable tube length-to-width ratios (3-to-1) and allowable handlebar shapes, and even dictates how far below the level of the seat the handlebars can be mounted (5 centimeters). To Sharp, the regulations are restricting designs that could push track cycling forward. "I think that the UCI rules are really making it difficult to have any big breakthroughs," he says. "It's like asking marathon runners to all wear a size 9 shoe."
Staff disagrees, saying the UCI is good about listening to feedback and making exceptions for anatomically different riders. "Rules and regulations are great, I think they're welcomed in this environment," he says. "Generally speaking, it's not a big deal, the rules they enforce."
Either way, engineers are putting a lot of resources into designing within the constraints. "It's kind of like Formula 1, but on a different budget," says Staff.
Integrated forks and stems are one such recent development. By building the handlebars and stem out of one piece of carbon, and fitting the fork into the head tube, engineers saved on wind resistance. High-pressure (220 psi) tubular tires is another upgrade, causing less friction with the track.
One of the simplest performance-enhancing features, though, almost doesn't enter the conversation: weight. Like Tour de France bikes, track bikes must exceed a minimum weight of 6.8 kilograms.
Strip a road bike of the gears, derailleurs, and brakes, and a lot of teams wind up adding weight to make the minimum. In some cases, that means they can add power meters without sacrificing performance, but in others, it simply means they must add ballast.
Originally, the rule was about safety, says Sharp. But he believes the strength of carbon fibre means even bikes below the limit can be safe. "I think it's an outdated rule, I think the technology has caught up to that rule," he says. "I've seen people put ball bearings in their seat tubes, and tape wrenches to their bottom brackets, and I don't know how that's safe either."
Source: Wired.com Image: Herbert Kratky / Shutterstock.com
This article was originally published by WIRED UK
