A group of young men huddle around a bicycle in a small shop named Carnival on the second story of a cream-brick building peering over the Yamanote Line in Shibuya.

A simple-looking red and white Faini racing bike, it has attracted a crowd because of a small sign hanging from its handlebars that says it once belonged to an Italian professional. The group aren't sporting Lycra shorts or showing off bulging calf muscles. Instead, one of the four is considering paying ¥300,000 for this purebred simply to ride it around the streets of Tokyo. The popularity of this type of race-proven bike, a stripped- down brakeless, one-geared machine known as a fixed-gear bicycle, has exploded in the past year.

American actor Jason Lee bought his Japanese Nishiki fixed-gear bike last year, and fashion designer Paul Smith sells the bicycles — hand-built in England to his specifications — in his shops (though at ¥661,500 you'd need to be a committed fashionista to buy one). Among Japanese celebrities, the man dubbed The King of Harajuku, DJ and pop producer Hiroshi Fujiwara, has more fixed-gear bikes than you can shake a bicycle pump at.