Springs: What Do They Really Do? An Insight Into Tuning
Slideshow: Spring rates are a vital part of car setup. Do you know what they really do? Let’s take a look at some things you might not know about this common modification.
Determine Wheel Rate
If you want to compare spring rates to another car you can’t simply use the lb/in. rating provided by the manufacturer. All cars have suspension systems that work springs differently. This is where wheel rate comes in. By dividing the spring rate by something called motion ratio you can come up with a way to universally compare spring values across various automotive platforms.
Balance The Car
Springs actually balance the handling characteristics of a car. If you jack up spring rate in the rear you may begin to induce oversteer where the car was settled before. Conversely, a car that is under sprung will handle like a boat and can be downright dangerous. As your tire grip goes up so does the demand a suspension system requires of the spring rate to keep the same balance. It’s always changing depending on grip.
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Work in Tandem With Shocks
Springs and shocks go hand in hand. While a spring's job is to soak up bumps the shocks job is to return it back to its original state neither too quickly, nor too slowly. Once reasonable spring rates are determined you will want to use sway bars to fine-tune your setup. Over springing a car without upgrading the shocks is a recipe for disaster as well. By properly valving a shock you can actually get away with running stiffer springs that don’t sacrifice handling.
Help in Weight Reduction
Springs often come in smaller diameters which can mean saving precious pounds to some racers. If you are trying to go for a super lightweight build do not discount the spring as part of the equation. Having said that do not buy cheap quality springs that will eventually sag causing you problems. Opt for high quality if you’re going to reduce weight.
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Aid in Aerodynamics
Why do race cars have super stiff springs? To keep the car level for aerodynamic purposes. When a car experiences body roll in the turns one side will go up higher than the other causing air to escape from beneath the underbody. This escaping air radically reduces downforce and can be detrimental in the middle of a corner. Another way springs do more than what they get credit for.
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In Closing
Springs do way more than just lower a car for better center of gravity and improved looks. They are dynamic tuning instruments that make up one piece of the larger puzzle. Understanding the principles of what makes a car fast—sticky tires, aerodynamics, good balance, etc.—will ultimately determine what direction your mods need to go in. Hope you enjoyed reading.
For help with service of your car, check out the how-to section on our sister site MustangForums.com