A coilover is an automobile suspension device. "Coilover" is short for "coil spring over strut". 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 for optimal damping without torsional loads. Some coilovers allow adjustment of ride height and stiffness, using a simple threaded spring perch similar to a nut. More advanced adjustable coilover systems will use a threaded shock body, coupled with an adjustable lower mount for ride height adjustment, while an adjustment knob is used to adjust damping, commonly referred to as "stiffness." Spring rate also plays a role in stiffness.
The coilover is a basic component of the MacPherson strut suspension system, which is distinguished from other arrangements by employing a particular design of anti-roll bar as a longitudinal constraint. This was the first widespread use of the coilover in automobile suspensions, but there are other designs. The word coilover should not be considered a synonym for the MacPherson strut arrangement.
Car adustable coilover set
Coilovers should not be confused with struts or independently mounted shock absorbers.
Coilover suspension systems have become a popular staple in the automotive aftermarket. Once limited to racing teams with the research and development budget to create performance parts, these suspension systems are now widely available from most online and retail aftermarket auto part merchants. There are 2 different types of coilovers, full coilovers and slip on coilovers. The full coilovers are matched up with a shock from the factory, while slip on coilovers are mostly just adjustible springs.
A coilover is not to be confused with the shock absorber and spring setup (strut); coilovers are totally independent and do not require extra parts e.g. bumpstops, ball Joints, spring cushions etc. Many people state that they are the same but this is a busted myth, hence the reason that high performance cars use independent coilovers to increase road grip, handling and comfort. On a lower budget, people will install a 'lowering kit' consisting of a spring that is of different measurement in length (mm) and fit aftermarket shock absorbers to increase comfort and handling on tighter corners where body roll may hinder performance. Coilovers come adjustable or a fixed length and normally bolt straight to a car instead of using tools (spring compressors) to fit a shock absorber and a spring to. While they are generally more expensive (up to 90% more), they still offer the greatest amount of comfort and handling compared to the earlier, strut-mounted type.