Why do we need gear reduction in automobiles?

Let's keep it simple, for a particular power output there can be multiple results. Power is proportional to the product of torque and rpm. So keeping the power as constant we get, torque is inversely proportional to the rpm. read more

To understand why a reduction gear is used in a particular machinery we will take an example of a ship using high speed turbines. It is a basic requirement of a ship that in order to have high efficiency the steam turbine should operate at a relatively high range of rpm. read more

If we change the RPM of the engine by controlling fuel injected, the speed of the car is automatically controlled. Why do we need gears which cause loss of efficiency while transmitting power due to friction, etc. read more

A gear ratio greater than 1: 1 is achieved when a smaller gear (reduced size) with fewer number of teeth meshes and drives a larger gear with greater number of teeth. Gear reduction has the opposite effect on torque. read more