What is a Coilover


The suspension system in your car improves its control and handling, giving you a smooth ride. The suspension system also provides comfort on uneven terrain.


What is a coilover?

The name coilover is a short version of “coil spring over the shock”. Typically, what you get is a coil spring that covers a shock or a strut.

How is it different? Most of the other suspension systems have the spring separate from the shock. In fact, most car owners buy the two components separately. However, a coilover comes with preassembled shocks and springs that are designed to fit each other and work in harmony perfectly. This will not only make your car look better by reducing the wheel gap, but also significantly improve the car’s handling and performance.

The types of coilovers are as follows:

  • Coilover Sleeves

Coilover sleeve kits resemble lowering springs. The key distinction is that they are height adjustable. You can choose from a wide range of rates and lengths. They do not include a shock or strut. They are installed on your existing shocks and come with top mounts. These are entry level suspension upgrades – they have affordable and do not come with a Camber Kit.

  • Height adjustable coilovers

The key feature of the height adjustable coilovers is height adjustability. This is a full-bodied coilover that comes with shocks. However, the shock is non-adjustable. That is to say, you cannot adjust the rebound, compression, and stiffness of the shock.

Different manufacturers have different designs. Most provide them pre-assembled with top mounts. These coilovers are a good option if you want to lower your car and choose the amount of lowering you want. With this type of coilover, you have to purchase a camber Kit separately.

coilovers damper adjust
  • Shock Adjustable Coilovers

These coilovers sport the same features as the height-adjustable coilovers. The difference between the two is the shocks. In the shock adjustable coilovers, the shock is adjustable and perfectly dials into the suspensions. The shocks allow smooth rebound and compression, adjusting the stiffness.

Shock adjustable coilovers are the most popular type of coilovers. They provide a smooth ride in your daily driving. Racers like them as they can adjust the stiffness – a feature that is crucial for track use. The price is mid-range, and they usually do not come with a Camber Kit.

  • Shock Adjustable Coilover with Camber Kit

A shock adjustable coilover with a camber kit is one of the best suspensions upgrade you can get for your car. These coilovers come with height adjustment and adjustable shocks. Normally, they feature a front camber kit, with some advanced versions sporting the rear camber kit.

How does a coilover work?

The typical suspension system features a controlling arm, coil spring, and a shock absorber or a strut. The difference between a strut and a normal shock is that a strut carries some of the weight of the car. Most of the time, the spring is mounted on the strut. In case of any compression on the strut, or the spring, or both, the wheel moves upwards towards the body of the car.

The mechanism of the coilover is similar. It has a longer coil spring that is coiled around the strut. For the upward movement of the wheel, both the shock and the spring must compress. The spring carries the weight upon compression while the strut transfers or damps the bouncing to the spring.

adjust coilovers

How to install a coilover in a car?

It is recommended that you get your coilovers installed at an auto shop. Still, a DIY installation is not out of the question. Depending on the manufacturer and model, coilovers are shipped in different ways.

You can either get them fully extended, collapsed, with the springs mounted, or with separate springs. The first thing you should do when you buy them is to inspect the contents of the package. You should determine that they are the right size for your car. Also, check that you have received sets for the rear and the front wheels.

Step 1: Install the Spring

Installing the springs should be the first step if the coilover comes with the springs separately. Most coliovers have an instruction manual detailing how to install the springs. Typically, you will have first to extend the shock. Then, slide the spring over the shock until it comes in contact with the spring retainer, also called the preload nut. If the coilover is dual rate, install the slider first before mounting the lower spring from the lower end of the shock.

After installing the lower spring and the upper spring, there should be zero preload. So, you should make sure that both springs are snug together. Also, at zero preload, there are no more than 3 inches of threads above the coil adjustment nut. Zero preload guarantees no play between the coil nut adjusters, the springs, the slider, and the spring plate.

Step 2: Install the Coilover

To install the fully assembled coilover, suspend the chassis using a jack and ensure the suspension is in full droop. Then, bolt the coilover using the right bolts (usually grade 8) with the lock washers and nuts. Lastly, lower the vehicle slowly.

If you did everything correctly, after the vehicle weight rests on the coilovers, it would settle at your desired ride height. If it is slightly below the ride height, you simply need to add the amount of preload. You add preload by rotating the upper coil adjustment nut down. However, if it settled way below or way above the desired ride height, you need to change the springs because the problem could be the spring rate.

Step 3: Test Run

Now that you have installed the coilovers and set the correct preload, you can go for a test run. The test run will tell you if the coilovers need shock tuning or shock valving. Your main concern on the test run should be the feel of the suspension. You want the coilover to achieve light handling, and also need the suspension to be strong enough to adequately support the weight of the vehicle.

MaXpeedingRods offers a variety of coilovers in both sport performance and street performance. You can contact one of our coilover specialists at MaXpeedingRods for further information about coilovers.


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