A car’s speed is indicated by the speedometer – the dial fitted in the front panel of the driver. The speedometer is made of a cable that is connected to a set of gears in the car’s transmission, a core shaft, and a magnet housed inside a metal drum called speed cup. As the vehicle moves, the gears turn the core shaft, which in turn triggers the magnet to revolve. This exerts a turning force on the speed cup causing the needle in the speedometer to rise. A control free movement is however, prevented with the help of a hairspring that helps bring the needle to “zero” when the car stops.

The first motorcycles were motorized versions of the bicycles. While the credit for inventing motorcycle has not been claimed by anyone, the first company to commercially produce motorized version of bicycle is Paris based Michaux et Cie. In 1860s, they manufactured cycles with steam powered “velocipedes” – speed-boosting pedals. The first self-propelled motorcycle however was a tricycle invented by Edward Butler in 1884. It was famously known as the “butler petrol cycle”. The popularity of these motorized cycles grew and soon bicycle-manufacturing companies started experimenting with smaller and sleeker motorcycle designs. It was however during the WWI that the idea caught on, and motorcycles achieved the fame that they enjoy today.