Switching speeds

Many bicycles have gears. The use of low transmission with less force allows you to pedal while lifting, the upper gear provides the high speed at moderate effort. In addition, some bikes have a gearbox built into the rear wheel hub. This type of miniature system that is used in many cars. Switching speed is achieved by using different combinations of gears inside the hub.
Another variety of systems of switching speeds that are used in bicycles, there is a dropping mechanism. On the rear wheel set of sprockets of different sizes, when you need it, the chain moves from one sprocket to another. When, for example, is selected high gear, the chain is on the smallest sprocket. As a result, one turn of the pedals leads to a relatively large number of revolutions of the rear wheel, resulting in more speed. Although many modern machines are still reminiscent of safe Bicycle of the last century, there are those which are based on Bicycle Moulton methods with small wheels, which appeared in 1962 these machines the diameter of the wheels does not exceed 35-50 cm, in contrast to conventional models where it is equal to 60-70 cm frame is F-shaped, with the top bar missing in it that makes the bike fit for men and women. Height of saddle and handlebar can be adjusted in a wide range.