One of the things that a lot of people think is that all automotive springs are the same. In fact, each vehicle requires a specific type of spring that will allow the suspension to work properly, and provide the driver and passengers with the best comfort and handling capabilities.
Modern suspension systems provide both a comfortable driving experience and handling, but if you want to increase either of these features, you’ll have to compromise the other.
When you drive over a bump on the road, the spring compresses in order to keep the car as stable as possible. Springs, in combination with shock absorbers, allow the wheels to move up and down to keep the cabin leveled as much as possible. Different types of springs react differently.
In this article, we’ll be talking about spring rate, spring rate conversion, and everything else you need to know about this important aspect of your car. Let’s jump right to the basics.
What is Spring Rate?
Spring rate is explained as the amount of force required to compress a spring by 1 inch, and the rate is measured in pounds, Newtons, and kilograms.
Depending on where you live and which spring model you have, you might need to convert these units.
Spring rate isn’t used only in the automotive industry, but in any other industry where springs are used. The same definition is used in every industry.
Unfortunately, it’s impossible to measure a spring rate without a proper spring rate testing machine. Some springs include the rate printed on the side, but in most cases, this is erased due to regular wear and tear. Otherwise, you can usually find the spring rate if you search for a specific car’s spring rate on the internet.
What Affects Spring Rate?
Obviously, springs are different in each vehicle model because of weight differences and use. When comparing different types of automotive springs, you’ll notice a clear difference in wire diameter, spring diameter, and the number of coils on the spring. All these have a specific effect on the spring rate.
When the wire diameter is larger, the spring rate is higher, which means the car will be stiffer on the road. This is why race cars seem to have thicker springs in the suspension compared to much larger off-road vehicles.
Spring diameter also has a significant effect on the spring rate. When the spring diameter is larger, the spring rate becomes lower.
Lastly, a larger number of coils in a spring decreases the spring rate.
All these features should be taken into consideration if you’re looking for new springs for your car. This information is most applicable when browsing used springs that don’t have a printed spring rate, and their origin is unknown.
Effects Of Different Spring Rates
As we’ve mentioned before, different vehicles use different types of springs. Springs used in regular passenger cars and off-road SUVs can’t be the same due to the difference in use. This is where the difference in spring rates is the biggest.
When the spring rate has a larger value, the vehicle will also be a lot stiffer. A higher spring rate is compatible with road cars, drift, and race cars. A lower spring rate is usually common with off-road vehicles that need to cover rougher terrain and where vertical wheel movement is important.
Fitting an inadequate spring on a car can seriously affect your ride quality, and even jeopardize your safety. When it comes to passenger cars, it’s of the utmost importance to stay as close to factory settings as possible. Track, drift, and race cars will benefit from having a stiffer suspension setup, unlike off-road vehicles which require a bouncier suspension setup that can overtake large obstacles on the road. Fitting a stiff suspension on an off-road vehicle would eliminate its off-road capabilities, whereas a track car would lose its handling capabilities, and would become extremely unstable both in corners and in straight-line sprints.
What is Spring Rate Conversion?
Spring rate conversion is a mathematical equation used to convert spring rate from one unit to another. Different springs have spring rates expressed in different units, so in case you need to replace your factory springs with different springs that are marked with different units, you’ll need to convert the units so the difference between spring rates wouldn’t be huge.
Spring rate is expressed either in imperial or metric units. The three main spring rates include units such as pounds per inch, kilograms per millimeter, and Newtons per millimeter.
The first thing you need to convert is the force. To convert pounds into Newtons, you’ll need to multiply the value of pounds by 4.448. If you need to convert pounds into kilograms, you’ll need to multiply the value of pounds by 0.4536.
Secondly, you’ll need to covert length units to be the same as well. Thankfully, there are only two units used for this – inch and millimeter. One inch equals 24.5mm.
If you need to convert the spring rate to metric units, don’t forget to divide your new spring rate by 24.5 to have the denominator’s value “1”.
Conclusion
A car’s suspension system is much more complex than people consider it to be. Aside from the parts that keep everything in place, there are a lot of other aspects that have important roles in how a car will handle, and how comfortable it will be. One of, if not the most underrated aspects of the suspension system is the spring rates that can have a significant effect on the car’s handling.
To find a proper replacement spring set for your car’s suspension, you’ll need to find a set with a proper spring rate. Sometimes, spring rates will be defined in imperial units, while other manufacturers use metric units. Spring rate conversion is a simple, yet important process to find the right set of springs for your car.
If you’re not interested in converting the spring rate yourself, you can look for spring rate conversion charts online where you’ll find some of the most common spring rates in both metric and imperial units.