"Now all the college kids want them because they have had courier bags for the last five years and now they want the bike to go with it," said Wirtanen.
The bikes are also popular with racers wanting to work on their form, commuters who ride in rain and snow, and, increasingly, with those taking up track racing on banked velodromes.
Some who ride them on the street simply buy production track bikes from companies like Bianchi and Fuji Bicycles, while others retrofit old steel road bikes into the "fixies" now often seen parked outside hip city bars.
Fixie is short for "fixed gear," meaning the rear wheel and the pedals are connected through a single gear anchored to the rear wheel.
Unlike standard road bikes, there is no way to coast, there is only one gear and brakes are optional.
