Shock absorbers

The springs help to keep the wheel in contact with the road are assisted by the shock absorber. Once the spring compresses it rebounds and this happens over and over, like oscillations on a screen. The shock absorber dampens this motion. 

The shock absorber does not absorb shocks (that’s the job of the springs), it dampens the effect of the oscillating springs. It achieves this by passing hydraulic fluid or gas between chambers. 

The shock absorber is a cylindrical chamber with a piston in the middle. The bottom of the shock absorber is attached to the lower suspension arm and the top is fixed to the car’s body. 

When the wheel hits a bump the piston moves up in the cylinder and fluid or gas passes through small valves in the piston from the top of the chamber to the bottom. 

When the wheel rebounds the piston moves down in the chamber and the fluid or gas moves in the opposite direction. 

This in effect dampens the motion of the spring and stabilises the body. 

The result is a comfortable ride and the wheels stay in contact with the road. The above components combine in various ways to make up the suspension system and there are two types of systems, the non-independent and independent suspension.