So you’ve purchased a set of racing coiloverss hocks for your car with spring pre load (or “spring tension”) adjustment, but do you know how to set it properly? Maybe your coilover system does not have independent ride height adjustability, you set it to yield the desired ride height, and are now just hoping the set pre load is within a proper range. Or maybe your coilovers do have spring pre load adjustability independent of ride height adjustability, but you are unsure of how this affects performance. In this article, we will describe the effects of spring pre load and how to properly set it.
Having too much or too little spring tension will negatively affect suspension performance, but in different ways. Too much spring tension can make your suspension feel like it is topping out. This happens because now the shock extends to its maximum length too suddenly, and this may unload your wheels from the road surface. Not enough spring tension can make your suspension bottom out excessively. Knowing these effects can help make the correct adjustments.
Let’s define a few terms to help understand spring pre load effects. The amount of stroke the season consumes at static ride height from the weight of the vehicle is called “droop.” And the amount of stroke left over at static ride height is called “compression stroke.” The total shock stroke is droop and compression stroke combined.
It is important to understand that spring tension does not affect the spring rate of a linear spring (most coilover systems come with linear springs). For example, increasing spring pre load WILL NOT increase the firmness of your linear spring. However, this WILL increase the amount of compression stroke you have which increases bottoming resistance.
Springs on most racing coilovers systems have to be pre loaded in order to retain a desirable amount of compression stroke at static ride height. For example; if you have a coilover with a 200 lbs/in spring rate carrying 800 lbs of weight, without any pre set spring pre load, the coilover will compress 4″ just from the static 800 lbs of weight acting on it. If this racing coilovers has a total of 5″ of stroke, this only leaves you with 1″ of compression stroke left over! In this scenario you must pre load the spring to insure you have more than 1″ of compression stroke. There is way too much droop in this scenario.
So we now know that spring tension affects droop. But what is the proper amount of droop to have? This varies depending on how much total stroke your coilovers have, so we treat the desired droop as a ratio of total shock stroke. In order to have an appropriate amount of droop, we recommend setting droop to be 30-40% of the total shock stroke (see equation below). Now you know that you have to adjust the spring tension on your coilovers to yield 30-40% droop!
How to set spring pre load:
You must first measure the total shock stroke of your racing coilovers (including the bump stop length). Then measure how much the coilover compresses when the vehicle is at static ride height. Subtract the compression stroke at static ride height from the total shock stroke to find the droop amount. Adjust spring pre load until suspension droop is between 30-40% of total shock stroke.
These days, it is almost a requisite to have coilovers in cars. Racing coilovers are known for the way they improve the balance of the car and eliminate chances of your vehicle rolling off. They do this by lowering the gravity center of the car. You can get ksport coilovers because they are sure to give you many benefits. However, cost can be a downside to coilovers. The following points will tell you everything you need to know about coilovers –
1. Meaning – A racing coilovers is nothing but a coil spring which is installed around and over the shock. It is this one collective unit which is called a coilover. Since racing cars require a lot of balance and shock resistance, that is where coilovers were first introduced. However, they soon became very popular because of their advantage to any driven vehicle.
2. Types of racing coilovers – There are mainly two types of coilovers –
BC Racing makes an application for almost all makes and models for a little under 1000bucks USD.
* True or Threaded racing coilovers – The body of these coilovers is threaded. You need to decompress the spring if you want to adjust the tightness and height of the coilover. This adjustment would raise or reduce the height.
* Sleeve Coilovers – The true coilovers are much more sophisticated than sleeve coilovers. The only difference is that instead of using a threaded structure, this coilover uses a sleeve on which the spring rests. Usually, a simple screw is used to hold the sleeve in place. Locking plates can also be used to stop the sleeve from moving. However, sleeve coilovers also tend to be noisier which is why they are not preferred that much.
Aurimas “Odi” Bakchis, is the CEO of Feal Suspension, Inc. and is also a professional race car driver. He has personally engineered Feal Suspension coilover systems to perform in a variety of applications and his success on track has proven the outstanding quality of his Feal Suspension products. Aurimas finished the 2015 Formula Drift World Championship as 2nd overall, has traveled the world drifting, taught a suspension seminar in Europe, and has been ranked as a Top 5 driver in the Formula Drift USA championship since 2014. His suspension expertise is sought by drivers ranging from the inexperienced to the professional.