Mustang Springs and Proper Lowering Practices

Replacement springs serve two main purposes: to alter the vehicle's handling and to lower its stance. When replacing your springs, it's wise to closely examine your needs. Are you looking to improve handling, and if so, by how much? If you want to lower your Mustang, how far do you want to go? The spring options and characteristics are nearly infinite, so properly planning a spring swap is important.

Measuring from the ground to the fender, below is a list of stock Mustang ride heights (Note: depending on how worn your springs are, your ride height can change):

• 1979-1993: 26" front, 26.75" rear
• 1994-2004: 27.5" front, 28.25" rear
• 2005-2014: 28.6" front, 29.3" rear
• 2015-2018: 28.5" front, 28.75" rear

Mustang springs go around the shocks and struts and help to control your vehicle, specifically when launching off the line or in a turn. Springs have progressive rates that take an increasing amount of force to compress the spring the same amount of height and there are linear spring rates that require just as much force to compress it the first inch as it would the third inch.

Progressive spring rates are considered to be better for daily driving and cornering, while linear spring rates are better for drag racing.

Springs are the easiest way to lower your Mustang, providing anywhere from a half an inch to two inches of static lowering. When you lower your Mustang with springs, you will want to also upgrade the bump steer kit, the shocks and struts, and caster camber plates. Springs are also a nice appearance modification as they help to eliminate that horrible factory wheel gap, dropping your Mustang, and lowering the center of gravity for increased nimbleness in the turns. Mustang lowering springs can drop your ride anywhere from 0.5” to 2”, but it depends upon the manufacturer and product line. Lowering springs offer a static drop that lowers your Mustang to a fixed height. Going any lower than 2” would make daily driving almost impossible and at the very least unbearable

One thing you want to want to pay close attention to is the fitment for the springs you’re considering. Lowering springs are designed to handle and distribute the precise weight of your Mustang evenly and accurately. You want to make sure to purchase a set of springs intended to support and lower your car to the listed specs. Some springs are made to support both coupe and convertible while some others are not; similarly, some springs are designed for both V6 and V8 models, while others aren’t. We encourage you to stick with a spring created with your year and model in mind to get optimum results in both handling and appearance. Springs will be tuned for a certain weight and will be intended for a certain type(s) of car.

Also keep in mind that lowering your Mustang doesn't come with a complete list of benefits. There are some downsides too. By lowering your ride height, you've also limited your suspension travel. Aftermarket springs will provide a stiffer ride, which is ideal for launching and cornering, but will make for a bumpy ride for daily driving.

• Lowering requires suspension components to work harder and ball joints, wheel hubs, tie rods, shocks, and struts are all under more strain
• The ride will be much firmer and may not be as comfortable when hitting bumps in the road
• A mild drop (1" - 1.5") would help any vehicle with increased handling performance while not substantially affecting ride quality or reducing life on the suspension
• Dropping the vehicle (1.5" or more) will produce a harsher ride and more frequent suspension component repairs. The vehicle will also require more heavy duty aftermarket components to keep the car's suspension true and straight. These include panhard bars (2005) and caster camber plates
• As you lower the vehicle further, you will also need to monitor your wheel fitment to ensure your wheels are not rubbing during turns or during periods of high travel

The Mustang has a natural tendency to sit a little higher in the rear than in the front. So some owners may find themselves simply wanting to level the car instead of lowering it. To achieve this, you’ll find a few kits on the market specifically for this task. Roush is one of the more commonly used sources for this sort of spring kit. 

The lower the car, the more important the rate becomes. This is because you have less suspension travel to absorb impacts. With the appropriate springs, however, you can lessen the stiff ride and save yourself multiple dentist trips. Your goals should also take into account what spring rate is ideal for your situation.

Ultra-Lite: The reasons you wish to change your springs also weigh into the equation. While most people simply want to lower their car for appearance reasons, there are some who are doing it from a performance standpoint. If you fall into the former category, you may want to use a lighter spring to keep the ride quality of your Mustang as close to what it was before. Springs in this category are referred to as Ultra-Lite Springs.

Sport: If you’re looking to tighten up the feel of the suspension, you may want to investigate Sport Springs. Sport Springs are a little stiffer than stock, but offer a good compromise between stock and some added performance. They are a middle of the road option for those looking to keep the stock ride, but aren’t going to do any serious track racing. Keep in mind I’m referring to road racing, not drag racing. We’ll discuss drag racing in a moment.

Competition: Competition spring rates throw ride quality out of the equation in favor of handling and performance. These types of springs are typically used for cars that see a large amount of track time. While they can be used on the street, ride quality will definitely be much harsher than with the stock springs. They will also be harsher than springs in other categories.

Drag-Springs: Drag racing springs are very different from the other types, but just as with the competition springs they are best suited for track use. The difference, when compared to the competition springs, is drag springs allow the suspension to have a much fuller range of movement. This is due to a softer spring rate which reduces cornering ability. The car will launch at the starting line with a little more authority, however, since the spring rate allows the weight of the car to transfer to the rear wheels better than with other springs. This helps the car hook up and get power to the ground.

Standard Rate Springs: are geared more toward those who don’t mind sacrificing some ride quality for ultimate performance. These springs will be firmer at all times, which doesn’t allow them to absorb as much of the road as progressive springs and offer a bit of a harsher ride even over small bumps. Standard springs have a spring rate that rises in a linear manner. While the spring rate can increase as the spring is compressed, it rises in a predictable manner. For example, at the first inch of travel, it may be a 50 lb. rate while at 2 inches it will be 100 lbs., and at 3 inches a 200 lb. rate.

While the rate will vary from spring to spring, the increase in rate is predictable. Standard springs are most often used for drag and road racing applications, as their linear rates allow the driver to more accurately predict how the suspension will react.

Progressive Rate Springs: are daily driver friendly and ultimately offer a comfortable ride similar to stock during normal driving conditions. Another benefit of progressive springs is they help to achieve higher performance when driving hard. These springs have larger gaps between coils at one end than the other. This allows the spring to compress and firm up to reduce squat during acceleration, body roll in corners and excessive nose-dive under hard braking. The rise in spring rate is not linear, allowing for a softer spring rate in the early stages of travel, but a much stiffer rate as the spring is compressed further. So while the first inch of travel may be at a 50 lb. rate, the second inch of travel may step up to a 200 lb. rate, and continue to increase from that point.

Progressive springs find more of a use on the street. Since they can have a much softer initial rate before they get stiffer makes them ideal for maintaining ride quality while still preventing the car’s suspension from traveling too far when necessary.

To put it simply: NEVER modify your stock OEM springs and other suspension components by cutting it up. This will very negatively affect your performance and handling. Cutting springs to lower the vehicle will unpredictably affect the spring rate and could cause damage to your vehicle. If you are looking to lower your Mustang, do it properly with the right parts that have been tested and vetted with rigorous R&D.