Safe bike

Modern bicycles, based on the safe design, have been developed in the 1870s, the Wheels about the same size had spokes and rubber tires, while the rear wheel was driven via a chain transmission. 1895 to secure the bike already had a pneumatic ( air-filled ) tires and a diamond frame, in addition to models for women, where the upper pipe has been omitted, to make room for dresses of the cyclists.
In modern mass produced bike frames are usually made of high quality light of stainless steel pipes, rims and hubs of wheels of steel and alloys, the spokes of steel wire. Pedals and cranks are set at short axis through the bottom of the frame. On this same axis is fixed the sprocket, which with the help of steel chains connected with the leading chain wheel mounted on the rear wheel hub. This sprocket includes a freewheel mechanism that allows the cyclist to down the mountain, not rotating the pedals.