Powercam

The Powercam comes in a container that looks like a medium-size pizza box. Inside, there’s a crank with a monstrous 60-tooth chainring matched with a more reasonable 44-tooth. It was invented by Larry Brown, an American engineer who bought a fancy bike, but who had trouble riding it up his halfmile-long driveway to his house.

Mike Barry Sr. not only has a Powercam in his collection, but also a 1984 article on the part from Bicycling, as well as a paper entitled “The Effect of Cam-governed Torque Modification on Human Power Generation in Bicycle and Similar Drive Systems.” This component’s heyday was the late ’70s and early ’80. Three-time Paris-brest-paris winner Scott Dickson used it in his 1979 attempt at the 1,200-km randonneuring classic. He later became an employee of Brown’s Houdaille Industries, which produced the Powercam.

So how does a man who can’t ride his bike up his driveway come to put a 60-tooth chainring on his bike? The device has a special cam you install at the bottom bracket. It changes the speed at which your feet move throughout the stroke. During the power stroke, your feet move faster than the rings. Your feet then move slower afterward. The rings, however, move at a constant speed. This setup is said to reduce the pedal resistance. As a result, a bigger gear, say that 60-tooth ring, seems much easier to push.

The instructions that come with the Powercam say that using it is “much like running or walking upstairs.” Also, you’re told not to spin. “Exert force only between 1 and 5 o’clock,” they read. Installation is a serious endeavour: you have to drill into the bottom bracket’s bearing cup. The product also comes with a one-year warranty.

Barry has had his Powercam for roughly 25 years. He remembers seeing an earlier incarnation of the device, called the Biocam, at the New York Bike Show. “I was quite impressed with it,” he said. “It’s a very complicated piece of equipment. It would be quite a collector’s piece if you could find one now.”– MP