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A set of coilovers.
Coilover used in the double wishbone suspension on a Lotus 7.
Coilover visible in the front suspension of a Microcar Virgo

A coilover is an automobile suspension device. "Coilover" 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 coilovers allow adjustment of ride height and preload, using a simple threaded spring perch similar to a nut. More advanced adjustable coilover systems use a threaded shock body, along with an adjustable lower mount for ride 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 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.

Coilovers are different from struts or independently mounted shock absorbers.

There are two 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 adjustable springs.

Benefits of Coilovers[edit]

  • Coilovers provide tight packaging for shocks and springs
  • Assembly line installation is easier with distinct packages
  • Easy replacement with aftermarket coilovers
  • Aftermarket coilovers can offer many adjustments including ride height

Disadvantages of Coilovers[edit]

  • Increases shock wear due to spring side load
  • Increased shock bushing wear
  • More expensive to manufacture than separate shock and spring

Selecting The Right Length Coilovers[1][edit]

Check Collapsed Length[edit]

Off-Road coilovers are not meant to be used as bump stops because the wiper seal is usually exposed externally. Follow these steps to make sure your shocks don't become the bump stops.

  • Collapse your suspension until it hits the bump stop
  • If you have rubber bump stops measure how far they can collapsed until they're metal to metal
  • Measure eye to eye length on the shock mount
  • Subtract the metal to metal distance from the eye to eye shock mount distance, this is your maximum collapsed length

Check Extended Length[edit]

Shocks need to have enough travel for a reasonable amount of down travel but without allowing drivetrain, steering or other components to bind.

  • Droop suspension while checking for bind on the drive shaft, cv joints, steering, or any other part
  • Test articulation and steering to be sure nothing hits or binds in every kind of motion
  • Measure eye to eye length again, this is the minimum extended length
  • Select shocks that are at least 1" longer than extended length to allow for limit straps to set full extension


  1. ^ "How To Select The Right Length Coilovers - AccuTune Off-Road". AccuTune Off-Road. Retrieved 2015-10-28. 

External links[edit]