What Is Spring Rate?

In this article, we will discuss everything you need to know about spring rates and what it all means. This article will consist mainly of the lowering spring vs. the coilover system. However, everything you learn will still be compatible with the coilover system.

Choosing the right suspension for your car is one of the first and most common modifications, besides wheels and exhaust. When it comes to choosing, you have some options to pick from. The most common choice would be lowering springs or “coil spring,” which is a great starting point for new Mustang owners or someone that daily drives their car without wanting to break the bank when it comes to a budget. Your other options are a coilover or air ride system. These two systems are generally much more expensive and allow users to adjust their ride height.

But before you decide to buy one or another, you need to know what you’re getting into. Your new suspension has something called a “spring rate.” Now, this is entirely different from your ride height. Let’s dive deeper and learn what spring rate means.

To simplify and make it easy to understand: Spring Rate is the amount of weight required to compress a spring one inch. The great thing is that this measurement is universal and applies to everything, including lowering springs up to valve springs. So if you have dealt with either one, you’re already going to understand what it all means.

If you have already started shopping for new lowering springs, you may have noticed two common phrases: Linear and Progressive. These are key factors to choose from before buying.

• Linear springs feature a constant rate, no matter how far the spring has been compressed or the amount of force. These constant springs are ideal for smooth surfaces, like the race track. They are designed to be spaced apart evenly when built to help on those smooth surfaces.



• Progressive springs (a more common choice) feature varying rates depending on how much the spring compresses. These compression springs are built with an unevenly spaced design to help with uneven terrain. For example, if you daily drive your Mustang, you will want this spring design when encountering dips or bumps in the road.

Now that you know the differences between the two, you may have noticed a lot of numbers when picking. Each number plays a crucial role in how your car reacts when driving.

Most people may assume that a specific spring rate or preload will change the height of your car. When in fact, that is not the case. Different preloads are designed to affect spring rate depending on the weight of your vehicle. If you’re looking to lower your car, you can choose between different drop heights and preload spring force.

If you decide to go with a stiffer spring rate, you must understand that the quality will be completely different from stock. If you plan on daily driving, you will feel more bumps, holes, and other imperfections in the road. The tradeoff will allow your vehicle to grip and stay planted in the corners. Your handling will significantly increase and let you feel for the car. But be careful, because if you choose a spring rate that is too stiff, it'll cause the suspension to jolt suddenly and make the vehicle very unpleasant to drive!

If you’re not sure what spring rate is suitable for your car, we recommend researching what other owners use on their vehicles. Suspension is something that enthusiasts should never look over. Take the time to figure out what works best before making your purchase.

As always, if you have any questions involving spring rate, ride height, or anything about suspension, email or give us a call and we'll be more than happy to get you started on your journey when it comes to modifying your Ford Mustang or SVT Lightning. Be sure to keep it with the Real Mustang Enthusiasts at LMR.com.