Another system, now little used, is the transverse leaf spring in which the centre of an inverted semi-elliptical spring is attached to the chassis, and each end provides springing for the corresponding end of the axle. Some extra linkages are needed to resist fore and aft forces on the axle. The wheel is attached to an axle in some way. The simplest way uses a live or beam axle. This is just a strong tube which carries the differential near its centre.
Half shafts run down the tube to drive the wheel hubs and thus the wheels.
The springs are attached to the tube. The tube has to be strong and together with the differential is a substantial weight. This weight is all unspring weight - it is between the spring and the road. Designers, especially designers of racing cars, go to great lengths to reduce unsprung weight because it has a serious effect on handling. When a wheel strikes a bump it is driven upwards, compressing the spring.