A bicycle is a vehicle with two wheels. A person rides it. The main part of the bicycle is the frame. You sit on the saddle and hold the handlebars to steer. Your feet push the pedals to move forward. The pedals turn a chain, and the chain moves the back wheel. To stop the bicycle, you use the brakes. The brakes are on the handlebars. A bicycle does not use gas; it uses human power to move. It is a simple machine.