Day to Day, February 6, 2007 · It's the latest, coolest thing in pedal-powered transportation: Bikes with no gears and no brakes. You'll find them on city streets from New York to San Francisco, mostly in the company of young, rugged-looking bicyclists.

Take a close look at Vincent Betette's bicycle, for instance. Betette is a bike messenger in Washington, D.C. He rides a sleek machine that is stripped down to the bare essentials: Two wheels on a light steel frame with curving handlebars of bare metal. There are no cables, and no gears — and there's no coasting, either. This is a "fixed-gear" bike; if the wheels are turning, the pedals have to turn too, the way bicycles worked 100 years ago.