What To Look For When Buying Coilovers

Categories: Ksport


Four key components to consider before purchasing coilovers.

The suspension of your vehicle is what ultimately determines how well it will handle. If your vehicle came from the factory with softer suspension, it will almost always handle poorly until the suspension is replaced with a performance setup such as coilovers. Old, worn out suspension also has a very negative effect on the handling and should be replaced, especially if used for any spirited driving where handling is key.

Coilovers help to set up your vehicle’s height and damping, which allows you to lower your center of gravity and stiffen up your chassis for better cornering and control. Not only does your car look sportier (and better in our opinion), but it is also a key step in allowing you to transform your car into a true performance machine, transferring your modifications into tangible wheel horsepower.

There are many different coilover brands and types on the market, so picking the right one can be daunting. Here are four key things you need to look for when buying coilovers.

Spring Rates

Springs are the integral part of your suspension set up. They control the vehicle’s ability to bounce, absorb bumps and create low body roll when loaded. Higher spring rates require more force to compress the spring, which reduces the amount of suspension travel. The body of your car moves when you accelerate, brake and turn. By reducing body movement, you make handling more predictable and effectively spread the cornering load across all four tires leading to better grip. Most aftermarket coilovers use significantly stiffer springs than OEM suspension, which improves handling and gives the driver more feel for the road and their car when performing spirited driving.

Spring rates are determined by the amount of pressure that it takes to compress the spring 1”. If your spring rate is 300 lbs. per spring, that means the springs will compress 1” per 300 lbs. of load. If you add another 300 lbs. to the springs, the spring will compress another inch to which the load on the spring is 600 lbs. while the rate of the spring stays its constant 300 lbs. per inch.

The ideal spring rate is different for each application. Whether you’re focused on drifting, drag racing or street driving, what suspension you chose will drastically change your cars performance. The selected coilover application changes internal shock valving to match the modified spring rate desired. Our Kontrol Pro Coilovers for example, use stiffer springs overall which, in conjunction with our monotube design damper, significantly improves handling. If you’re in need of stiffer suspension, we offer a wide range of variations of spring rates built to handle specific uses such as drifting, drag racing, rally, auto-cross and more.

Spring and Valving Adjustability

One of the many reasons anyone purchases a set of coilovers has commonly been to lower their car. The lower center of gravity will help reduce excessive body roll and improve performance. Having the adjustability for ride height, spring preload and damping are essential features of a high quality coilover. Adjusting your coilovers can help you fine tune how your vehicle handles and give it the perfect ride height for your application. The ability to replace the springs with stiffer springs is also an important feature as track cars need much higher spring rates than street cars to gain grip, improve handling and reduce body roll. If you swap to a stiffer or softer spring, it is important to match your spring rate with your damping to avoid a bouncy ride which is ultimately detrimental to handling. Taking this into consideration, all Ksport coilovers have been designed with ride height, spring load and damping adjustment as standard features.

What to look for when buying the best coilovers

Top Mount

On top of the coilover is a mount that holds everything together and bolts the top of the coilover to the car. This mount is known as the “Top Mount” and between the mount and strut assembly are two different types of bushings, rubber or pillowball type.

As you might expect, OE manufacturers use rubber bushings because it deflects more and is a primary cause for the failure of suspension precision. The rubber you will find on most OEM struts is soft and allows a lot of energy deflection. A stiffer rubber mount improves longevity and reduces energy deflection.

A pillowball bushing is a metallic spherical joint which, rather than deflecting from the cornering forces like a conventional rubber bushing, pillow ball mounts do not move at all. This translates into a far more precise feel from the suspension and steering. The metal bearings will transmit far more vibrations from the road, which may make the vehicle less comfortable for daily use but is essential for increased performance in racing applications.


Monotube vs. Twin Tube Damper

Inside any coilover there are two designs of dampers you will come across, monotube and twin tube.

The twin tube uses an inner and outer tube, twins if you will. The inner tube holds the piston shaft, valve and oil while the outer tube holds damper oil and nitrogen gas. Here’s how it works – when the suspension is compressed, the piston forces oil out of the inner tube by its valve and into the outer tube. When the piston moves back into position, the oil is sucked from the outer tube back to the inner. Most OEM suspension utilizes the twin tube damper set up because it allows for more suspension stroke and improves ride quality.

Alternatively, monotube dampers hold the gas and the shock in one tube, separating the liquid from the gas with a floating piston. This design pushes the damper piston through oil and pushes the oil through chambers through the valves in the piston itself. This allows the gas to be compressed and react quicker, by compressing slowly over small bumps and quicker through larger bumps. One incredibly important detail about the monotube design is its ability to be used either way up, unlike most twin tube dampers. Compared to the twin tube design, the monotube holds more fluid, has better heat dissipation and improves the responsiveness of the damper.

For the best performance on the street or track, the monotube design is a superior upgrade to the twin tube design.


Above all, it is important to buy coilovers from a knowledgeable and proven company who stands behind their products with a solid warranty and good customer service. Good spring rates, spring and valving adjustability, pillowball top mounts and a monotube design are all great ways to spot a high quality coilover.

We hope this helped clarify all the options you have when it comes to choosing a coilover setup that is right for your build. If you have any questions on exactly what you might need for your setup, please don’t hesitate to contact our team.