GRADES 9-12
AERODYNAMICS OF CYCLING

BACKGROUND INFORMATION: Bicycle Aerodynamics The bicycle was developed over 100 years ago. One of the first bicycles was the ordinary or high wheeler bicycle. This bike had a large front wheel and an extremely small rear wheel. The speed one could travel on this bicycle depended on the size of the front wheel. The larger the wheel, the faster the bike. This design was limited to tall riders and this bicycle was short lived. By 1880, the modern bicycle appeared and was known as the safety bicycle. In the early 1930's a strange new bicycle design appeared out of France. The rider of this bicycle sits in a low easy-chair position. This translates to a much smaller frontal area and, therefore, less drag. This bicycle, the velocar, was so efficient that an unknown rider was able to defeat the best riders of the day as well as break most existing records. This led to a furious debate about whether the velocar was a bicycle or not. In 1934, the UCI (Union Cycliste International) passed a series of rules against the use of recumbent bicycles. Views And Data Displays In The Allied Aerospace Wind Tunnel Athletes Can Watch How Their Drag Changes On The Video Monitor With Permission and Courtesy Of Allied Aerospace The velocar proved that aerodynamic drag plays an important role in cycling. In fact, at 8 mph (3.5 m/s) the aerodynamic drag of a bicycle and rider is greater than the rolling resistance (the friction between the road and the wheels). When the speed increases to 20 mph (11m/s), the aerodynamic drag is more than 80% of the total drag. So, how does one improve upon the aerodynamics of a standard bicycle? By looking at a bicycle and rider, there are several areas for aerodynamic improvement. The most important area is with the rider position. Aerodynamic improvements can also be made for the frame, wheels, and individual components.