How do you make a bicycle that never needs lube, never leaves grease on your pants, and always delivers smooth pedaling? Simple: Ditch the chain.
For its new Soho commuter bike, Trek replaced greasy metal links with a dry belt. Unlike other attempts at such bikes, the Soho is silky smooth to pedal. And it’s the first to offer multiple speeds, using an eight-gear transmission inside the rear-wheel hub.
Trek recruited Gates Technology, maker of belt drives for Harley-Davidson motorcycles, to fashion a belt from carbon fiber and rubber that’s squeaky-clean and doesn’t stretch out. The biggest challenge—a two-year endeavor—was designing the perfect fit between the teeth on the inside of the belt and the aluminum cogs on the crank and rear wheel. Make the teeth too long, and the belt would snag on the cog, slowing the bike down. Too short, and the belt would slip.
For its part, Trek engineered thick frame tubes on the back of the bike that won’t flex under hard pedaling and slacken the belt. So you’ve got a bike that’s not only easy to ride, but easy to maintain.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.