Briefly, the transmission is a drive train, which consists of a number of mechanisms that serve for transferring power from the engine to the driving wheels of the car (more correctly, to the propellers, but for simplicity we use the term “wheel”) and allow changing the weight the value of this effort according to the driving conditions. Not every engine, or rather, none of the internal combustion engines, achieve power and torque from the minimum, initial speed. But in order to get under way, it is necessary to transfer almost maximum torque to the drive wheels. Moreover, it needs to be increased. Starting a movement is always more difficult than maintaining it. Maximum torque is only achieved at certain crankshaft rotations. Thus, transmission elements with several pairs of gears (manual transmission) that are designed for reducing the number of revolutions on the driving wheels with a simultaneous increase in torque are installed after the engine. The crankshaft of the engine rotates, for example, at 2000 rpm. And the wheels, thanks to the transmission, make only 200 rpm, or even less.
Many had, or may still have, a bicycle. A bike with the ability to switch speeds was a real child dream. Everyone experimented by changing gears. Having switched on the lowest speed, it was easier to start movement. But at the same time it was necessary to work the pedals more intensively. As the speed increased, the gear was shifted up and, as a result, the pedals were rotated more slowly and the wheel was spinning faster.