Physics of Cycling :: physics sport sports cycle bicycle

Almost the entire spot of cycling is based on physics. Some aspects are obvious, like torque and other basic forces, although others do not come to mind as easily. Things like aerodynamics are playing an increasingly larger role in the sport, along with other things like damped harmonic motion (think mountain bike suspension), and efficiency. A lot of the detailed things would be beyond this paper, but the basics, which are the most import parts, will be talked about. Torque is what makes the wheels on the bike go round. Great research has been but into the sport in order to figure out how to increase the torque applied by the rider to the rear wheel, wile decreasing the torque required to make the wheel turn. Torque is produced the rider using a device called a crank. The torque in the series of parts that drive the bicycle forward (called the drive train) is dependant on the size of the chain ring (the large gears mounted on the crank) being used, and the size of the rear cog being used. When the chain is on the smaller chain ring, the force through the chain must be greater because the chain ring is closer to the axis of rotation and must apply a larger force to equal the torque produced by the pedals. Likewise, if a larger cog is used in back on the wheel, an larger torque is exerted on the wheel, and so produces a larger forward force at the tire. These higer-torque gears are good for climbing, where large forward forces are need at low speeds, but for flats and downhills, different gearing is needed, because the lower gearing does not provide much forward rotation (the rear wheel will not rotate as much for a single stroke of the pedal). Detail of the drive train on a bicycle. The smaller the gear on the crank combined with a large gear on the wheel will produce large amounts of torque and large forward forces. Work and Power Although torque does have a lot to do with the bike and how it works, professionals and people in the know don't usually refer to torque the rider applies to the wheels. Usually, they'll talk about power. This makes much more sense, because cycling, in general, is a sport that requires you exert yourself for a relatively long amount of time, instead of just trying to exert the largest force you can (this isn't weight lifting).