A coilover suspension is an automobile suspension device. “Coilover suspension” is short for “coil spring over shock”. It consists of a shock absorber with a coil spring encircling it. The shock absorber and spring are assembled as a unit prior to installation, and are replaced as a unit when the shock absorber has leaked. This provides damping without torsional loads.
Some coilover suspensions allow adjustment of ride height and preload, using a simple threaded spring perch similar to a nut. More advanced adjustable coilover suspension systems use a threaded shock body, along with an adjustable lower mount for height adjustment, while an adjustment knob is used to adjust damping. Stiffness is changed by switching the spring for one with a different spring rate.
The coilover suspension style of spring placement is a component of the MacPherson strut suspension system, which uses a design of anti-roll bar as a longitudinal constraint.
Coilover suspensions are different from struts or independently mounted shock absorbers.
There are two types of coilover suspensions, full coilover suspensions and slip on coilover suspensions. The full coilover suspensions are matched up with a shock from the factory.