Coilovers are one of the most popular suspension upgrades — but what exactly are they, how do they differ from stock suspension, and are they right for your car?
The word "coilover" is short for "coil spring over shock absorber." It describes a single unit that combines both the spring and the shock absorber into one compact assembly — hence the name. Your factory suspension most likely keeps these as separate components.
On most stock cars, the spring and shock are either separate units bolted together (MacPherson strut) or mounted in completely different locations on the car. A coilover wraps the spring directly around the shock body, which allows the entire assembly to be more compact, adjustable, and tunable.
Simple version: A coilover is a spring and shock absorber combined into one adjustable unit. Instead of two separate parts you cannot tune, you get one integrated unit you can adjust for ride height, stiffness, and handling balance.
To understand coilovers you first need to understand what suspension actually does. Your car's suspension has two jobs that sound contradictory — it needs to keep your tyres in contact with the road at all times, AND it needs to absorb bumps so passengers are not shaken apart.
These two jobs are handled by two different components working together:
On a coilover, both of these components are integrated and — on quality units — independently adjustable. You can change the spring rate by swapping springs, and change the damper stiffness by turning an adjustment dial. This level of tuneability is simply not possible with factory suspension.
The biggest practical difference most drivers notice is body roll. Stock suspension on a typical road car allows the body to lean significantly in corners — this is by design, as it feels natural and comfortable to most passengers. Coilovers with stiffer spring rates dramatically reduce this lean, giving the car a flatter, more connected feel through corners.
When a coilover is described as "adjustable," it can mean several different things depending on the price point. Here is what the terms actually mean:
Almost all coilovers offer this. A threaded collar on the shock body allows you to raise or lower the car by rotating the spring perch up or down. This is how you get that lowered look — you are physically shortening the distance between the wheel and the body. Most coilovers allow 20–80mm of height adjustment.
Mid-range and higher coilovers include a numbered dial — usually 1 to 32 clicks — that controls how stiff the shock absorber is. Turn it toward soft for a more comfortable daily drive. Turn it toward stiff for a track day. Entry-level coilovers often skip this feature, giving you fixed damping.
On high-end coilovers, you can swap to different springs with different rates. This is mainly relevant for serious track use where you want to optimise for specific circuit conditions. For road use, the springs that come with the kit are usually appropriate.
Practical tip: For a daily driver that occasionally sees a track day or canyon run, a mid-range coilover with ride height and damper adjustment is the sweet spot. You can run it soft enough during the week to be comfortable, then firm it up before a spirited drive.
Coilovers are one of the most transformative modifications you can make to a car — but they are not for everyone. Here is an honest assessment:
The most important thing to understand is that coilovers involve a trade-off. A stiffer, lower car handles better — it simply does, the physics are clear. But it also transmits more road noise and vibration into the cabin. Where you set the balance depends entirely on how and where you drive.
For most enthusiasts who drive on decent roads and want their car to feel alive and responsive, a quality set of coilovers from brands like BC Racing, KW, or Bilstein will be one of the most satisfying modifications they ever make.