Bike computers and speedometers
A tachometer measures the current speed and displays it graphically. The term comes from ancient Greek and is composed of "tachýs" (fast) and "mýtron" (measure, standard). Usually, the speed is displayed either analog with a tachometer needle or digitally. Many modern speedometers also include many other functions such as an odometer, a clock, an altimeter or even a calorie counter. For cyclists who often find themselves in unfamiliar territory, a navigation device in the form of a speedometer is also a good idea.
