The sprung weight refers to the weight which is supported by the suspension springs. The weight of the vehicle’s body, frame, engine, transmission, interior, fuel, and passengers constitute the sprung weight.
The un-sprung weight refers to the weight which is not supported by the suspension springs i.e. weight of the components between the springs and road surface. The un-sprung weight includes the weight of wheels, axles, steering linkage, and some suspension components. It may be noted that un-sprung weight should be kept as low as possible to achieve pleasant ride.
