A Beginner’s Guide to Coilover Upgrades
We all know you can only stop as well as your tyres can grip, no matter the size of the brakes. We also know you can only turn as well as your tyres can grip. See the connection? Grip. And a good suspension setup will help you maximise grip. However, a tuned suspension setup is no walk in the park. There are numerous variables to think about when it comes to your car’s four legs. I mean, who wants their car to handle like it’s got a charley horse. So understanding the following three areas is key.
Types of Coilovers
When it comes to deciding the right set of coilovers suitable for your driving style, you need to know the different types. Let’s start off with the basics.
An OEM “Spring-Over-Shock” assembly is usually a non-adjustable setup. In this type of setup, the spring surrounds the standard shock/strut. Deciding the right strut/shock and spring combination is important when using kind of install. It’s best to do a bit of self-research for proven setups before going down this route.
A Slip-Fit Coilover assembly is an inexpensive method to lower your car without doing major modifications to your current shock/struts. This assembly consists of a spring, jam nuts for height adjustment, and a hollow threaded tube sitting on the shock/strut’s perch. Since there are no performance benefits to this setup, I strongly advise not to track with this sort of setup.
A Full-Bodied Coilover assembly was probably what you were thinking of at the beginning. This setup replaces the entire factory spring-and-shock assembly and features a threaded body for easy height adjustments. Some may include damper control as well, depending on the model you purchase.
Basic full-bodied coilovers are similar to the slip-fit coilovers. It runs a series of jam nuts also to compress the spring and adjust your height of the car, but the benefit here is the manufacturer usually picks the right spring-and-shock combination.
Even though this sort of setup has improved performance over the slip-fit setup, there’s still a chance of bottoming out on a really low car. To get around this, high-end full-bodied coilovers include a lower threaded body with height-adjustable lower mounts.
Springs and Shocks
Springs and shocks are fundamental parts to keep tyres on the ground. Without either one of these components operating in perfect harmony, negative performance starts to exhibit.
Springs are designed to absorb energy from any bumps the wheels encounter. This is achieved by the compression of spring. When the absorption finishes, the stored energy is released forcing the wheel down again. They also reduce body roll, acceleration squatting and brake diving.
Spring rates should be selected with care prior purchase. If the springs are too soft, then the likelihood of bottoming out is higher. If the springs are too stiff, then the full traction of your tyres cannot be utilised.
Shocks control and dissipate the energy created from the springs by converting it to heat energy. This heat energy is then cooled by the internal fluid passing through small holes in the piston head of the shocks. Without shocks, the energy will continue to compress and decompress repeatedly until the energy completely diffuses.
Preload/Compression and Rebound
Preload is the pressure applied to the spring based from how far they are compressed. Dependent on the situation, sometimes adding preload can help with tyre traction. Having excessive preload will have a negative effect, so it is important to have the optimum amount.
Compression and rebound are two important words you need to understand when upgrading to coilovers. Compression occurs when the piston head moves into the shock’s body, compressing the hydraulic fluid into the lower body. This also controls the movement of unsprung mass (wheels, tires, brake rotor, callipers, etc). On the hand, rebound occurs when the piston head pulls away from the lower body, and thus controlling the movement of sprung mass (chassis, engine, driver, etc).
Common full-bodied coilovers come in two types: manufacturer preset and single-adjustable. To no surprise, preset shocks are set according to manufacturer standards. While single-adjustable shocks allow you to adjust the dampers accordingly to the way you want it. Common single-adjustable shocks generally affect low-speed rebound and slightly affects compression.
And that’s pretty much it. If you need further tips on what you need to look for when swapping wheels, click here.
Cover photo by Kenny Ng