The (Still) Mysterious Physics of Riding a Bike

Science nearly has bicycles figured out. Researchers have a good grasp on why bikes can balance by themselves, and are getting better at keeping them standing up in bike share stations. What’s less understood, says Stephen Cain, a researcher at the University of Michigan’s Department of Mechanical Engineering, is how people stay on bicycles.

On the surface, it’s a strange space for scientific analysis. Most people know how to ride a bike—about 94 percent of Americans, according to a recent survey. There seem to be few big-budget industries that stand to gain by understanding the evidently complex biomechanics of riding. Furthermore, researchers already understand the most basic basics of biking: riders keep their center of mass over the wheels, using steering and body movements (a lean here, a lean there) to guide this, the most elegant of machines.