Jim Wirtanen spent 12 years as a bike messenger dodging buses and cabs on the streets of Boston. He earned the name "Deadguy" after being hit by a speeding Lincoln Continental on the third week of the job. The collision threw him 40 feet across an intersection and he hit his head on a light pole.
Wirtanen recovered, returned to messaging and for the last 6 years of his career, delivered packages and legal documents using a brakeless, single-speed bike known as a track bike.
Though a bike with no brakes sounds insane to many, Wirtanen swears by it.
"Basically, a track bike is the perfect invention," said Wirtanen, who now works as a mechanic at Harris Cyclery. "You can't make it any better."
Wirtanen is far from alone in embracing the most basic bicycle technology in an age where major bicycle companies focus on the latest in high-tech gear, including full-suspension mountain bikes with SUV-strength disc brakes and ultra-lightweight titanium road bikes with carbon-fiber everything.
Long a favorite of fearless bike couriers, the "fixie" is growing in popularity among young urban American cyclists, who love the bike's pure lines, low price and street cred.
"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.
Simply put, when the wheels are moving, the rider's legs are moving.
As with a child's Big Wheel, if you want to stop, you have to use your leg muscles to slow the bike.
Many riders, but not all, add a front brake, but the pure and brave (or foolish) of heart scoff at the notion.
Oddly, when this configuration was first introduced in the late 19th century, it was known as a "safety bicycle," since it replaced the "high wheel," whose enormous front wheel made for an unstable ride.
Though hand brakes and free wheels were invented soon after, the fixed gear remained a popular bike for decades, including during the early years of the Tour de France.
One modern-day devotee, a former mechanic at San Francisco's Pedal Revolution who goes by the name Moon, compares the simplicity of his current fixie to the BMX dirt bike he rode as a teenager.
"Learning how to ride a fixie was like drinking decaf your whole life and then suddenly having the real thing," Moon said.
Learning to slow a bike with your legs and cornering while pedaling makes one a better cyclist, according to Wirtanen.
Though Wirtanen's shop tries to make sure all nonexperts install brakes, he waxes poetic about the thrill of a pure track bike.
"You take the brake off and you can't get any crazier for field testing your skill level than playing in traffic on a track bike," Wirtanen said. "If you are an intelligent cyclist, it makes you far more aware. Instead of looking a car or two ahead of you, you have to look three to four blocks down the road and have to scan left to right constantly to look for escape routes."
"It's a Zen thing. Once you get used to traffic, then you can float through the chaos," he said.
Sam Murphy, a San Francisco-based photographer who has been riding her brake-equipped fixie for two years, is surprised at how many brakeless fixies she sees parked in San Francisco's bohemian Mission district.
Though she loves the feeling of "total control over everything" she has on her fixie, she worries that many are ridden by inexperienced female riders whose boyfriends convinced them it was cool.
"The trend is a little scary in some ways, but I'm just glad to see more butts on bikes," Murphy said.
