Kehräyspyörä

Kehräyspyörä, also known as a derailleur, is a mechanical component used in bicycles to change gears. It consists of several parts, including the derailleur cage, which houses the jockey wheels, and the shift mechanism, which allows the rider to change gears by shifting the chain between different sprockets on the rear wheel or cassette. The derailleur is typically mounted on the frame and is connected to the shifters, which are operated by the rider's hands. There are two main types of derailleurs: front derailleurs, which change gears on the front chainring, and rear derailleurs, which change gears on the rear cassette. Derailleurs are essential for providing a wide range of gears, allowing cyclists to adapt to different terrains and riding conditions. They are available in various materials, including aluminum and steel, and can be adjusted to accommodate different chainring and cassette sizes. Proper maintenance and adjustment of derailleurs are crucial for ensuring smooth and efficient gear shifting.