In this (Part 1 of 2) suspension components guide, we'll clarify the differences between "replacement" (OE factory style) and "performance" (aftermarket) types of springs and struts/shock absorbers. For the purposes of this article, we'll often use the word "shocks" when referring to both struts and shock absorbers.
We'll discuss the different styles of springs and shocks that exist, and we'll note how replacement and performance versions of each differ - along with general advantages and factors to consider when shopping for them.
If upgrading springs and shocks to improve handling, comfort, or even change ride height has always been on your wish list, there's never a bad time to go forward with the changes. But making upgrades at the point when your old springs and shocks are worn out makes a great deal of economic sense. Since you've gotten your full money's worth out of those existing parts, spending a little more for exactly what you want now means just that - spending only a little more. Time and labor must be spent removing old suspension parts anyway, no matter what you decide to replace them with.
To provide you with some background information, browse our free online library of helpful articles, including "How Do Shock Absorbers Work?", "Coil, Leaf, & Torsion Bar | Describing the 3 Different Kinds of Springs", "Shocks Versus Struts: The Big Answers Revealed!", and "Stock vs Performance Suspension".
Start With The Right Tools For The Job
Having the right suspension tools BEFORE you start working makes everything quick, easy, and doable for the home mechanic. And most importantly, it ensures you won't have to put things back together half way through finishing because you didn't have a necessary tool to get past a certain point. Performing repairs yourself can also save you a good deal of money versus paying a repair shop - especially over the course of a lifetime of suspension work.
For more on this subject, we invite you to read our article What Special Tools Are Available For Suspension Repair? We discuss tools that make it easy to press out bushings, compress springs, separate ball joints, loosen shock tower bolts, and more.
Springs play a major role when it comes to safety, ride quality, and handling ability. Not only do they keep a vehicle at a designated standing height by supporting its full weight, they provide recoil necessary to bounce back after suspension components move up and down over uneven road surfaces. Springs can be soft and bouncier, or they can be stiffer and less bounce-prone.
There are three main types: coil springs, leaf springs, and torsion bar springs. These types of springs are not interchangeable with one another, and all must be replaced with like kind only.
Replacement Coil Springs
If you're happy with the contribution to ride quality and handling that your factory springs provided during their lifespan, you'll find satisfaction and value with our OE style replacement springs. These are built to match the overall dimensions, thicknesses, compression rates, tensile strength, and on-the-road performance for your specific year, make, and model vehicle.
They'll install without any modifications or adjustments. While they're being replaced, it makes sense to install new spring seats (top and bottom rubber insulators) because they wear out and lose their cushioning resilience as well. Check boxes along the left of the screen will also let you browse through our assorted mounting brackets if you should need them, and adjusters/shims which provide additional support or adjustment to the original mounting position.
Performance Coil Springs For On-Road Handling
If you're looking to modify your suspension, performance coil springs will give you the edge you need.
Keep in mind that variable rate performance springs allow better absorption of bumps during normal street use, then become stiffer around turns to reduce body roll during aggressive driving. This is ideal for performance-oriented cars with a low ride height. In this section, as with all types of springs, you'll find check boxes along the left side of the screen that let you select products with just the amount of ride height drop or increase. When using these checkboxes, it's important to enter the year, make, and model of your vehicle so our system can display applicable products.
Performance Coil Springs For Off-Roading
Performance coil springs can also be configured to allow for a greater amount of up and down wheel travel during off-road applications, which is a huge advantage on rutted and rocky off-road trails. For those who seek maximum wheel articulation for rock climbing or more aggressive off-roading, we've got Performance Lift Kits (from 4" to 10" of height increase) that allow you to do a suspension rework on your vehicle. Many of these kits include taller coil springs, extended-length shocks, and even spacers (see below).
Performance Coil Spring Spacers
Also solidly in the "performance" category are basic 4x4 suspension lift kits that use spacers positioned underneath standard-height coil springs to raise ride height between 1 and 3 inches. With minor amounts of lift like this, standard-length shocks can usually be kept in place.
And if you're not a fan of the nose-down suspension settings most modern 4x4s come from the factory with to achieve better aerodynamics and mileage numbers, leveling kits allow you to raise the front ride height back up - in effect, "leveling" your truck to a more heavy-duty stance. So if you plan on hooking up a plow attachment, leveling kits will serve you well. Some kits such as the DayStar ComfortRide Leveling Kit and ReadyLIFT Leveling Kit come with spacers to raise only the front end, while others such as the Pro Comp Coil Spring Spacer Lift Kit lift all four wheels - raising the front more than the rear.
Replacement Leaf Springs
If you're happy with the contribution to ride quality and handling that your factory leaf springs provided during their lifespan, you'll find satisfaction and value with our OE style replacement leaf springs. These are designed to install without modifications or adjustments because they're built to match overall dimensions, thicknesses, compression rates, tensile strength, and on-the-road performance of your specific car or truck.
For related OEM style leaf spring replacement needs, we've also got shackles, spring eye bushings, bumpers/insulators, spacers/shims, and assorted hardware pieces. These will help restore your ride quality to factory new specifications.
Performance Leaf Springs
If you're interested in modifying your factory leaf spring setup to handle increased power, see our page for Performance leaf springs. There, you'll also find lowering kits to drop ride height as well as lift kits to raise it with extra leafs ("add-a-leaf" kits) and/or leaf spring blocks. Plus, we've got additional beefed-up hardware pieces such as shackles, leaf spring pads, mounts/brackets, sturdier polyurethane bushings (instead of rubber), and more.
Performance-wise, leaf springs do have some disadvantages. Since they're bolted directly to rear axle assemblies, torque generated during hard acceleration or braking can cause axle wind-up. In cases of high torque engines, this means wheel hop and vibration, rear-end squat, and nose-diving. To prevent these conditions, leafs must have a stiffer spring rate - changing the ride comfort level dynamic that softer springs provide.
Performance Rear Leaf Spring Spacers
If you're interested in lifting the rear of your vehicle but prefer to keep costs down, leaf spring lift blocks are an alternative to new springs and shocks. These are available in height increases ranging from 1 to 8 inches. Taller lift blocks over 4 inches, however, can increase the likelihood of spring wrap mentioned earlier.
Leaf spring spacer blocks will come with longer u-bolts to secure things in place. Keep in mind that the longer u-bolts are, the more likely they are to loosen up and stretch a little. To compensate for this, you'll want to re-torque the nuts periodically to ensure components are securely in place.
Because installing leaf spring lift blocks on the front axle is not recommended for safety reasons, few front blocks are available. More specifically, if those front lift blocks should slide out of place due to loose u-bolts, steering would suddenly become dangerously difficult if not impossible.
Torsion Bar Springs
Replacement Torsion Bars
Like other types of springs we offer, our "Replacement" torsion bars mirror all dimensions, thicknesses, twisting rates, and strength found on your vehicle's original equipment ones. So the new ones will fit right in place easily without modifications.
For related OEM style torsion bar replacement needs, we've also got replacement keys, torsion bar end covers, adjuster pieces (to change ride height), mounting brackets, loader/unloader tools, and adjustment bolts & nuts. These will help fully restore your ride quality to factory new specifications.
Performance Torsion Bars
Performance torsion bars are built with a stiffer spring rate that results from denser (or thicker) metal that doesn't twist as easily. Stiffer torsion springs are ideal for 4x4s that go pounding over rough terrain, and they help some classic performance cars reduce body lean, brake dive, and bottoming out against bump while maintaining suitable ride comfort.
Traditionally, torsion bars are made from solid steel. But in the performance category, we've got a few torsion bars that are hollow inside. Because of various alloy blends that are used, these hollow bars can maintain necessary strength levels while being lighter in weight. Hollow torsion bars such as the MPD Racing Hollow Torsion Bar and Diversified Machine Torsion Bar are also known to have a slightly quicker response rate. If you've got a sprint car, the M&W Aluminum Torsion Bar keeps you on the path with even more weight savings thanks to aluminum construction.
Shock Absorbers & Struts
Shock absorbers are a major contributor to your ride comfort and safety because they are the suspension item which stops the springs on your car or truck from bouncing up and down endlessly after a bump.
Replacement Shock Absorbers and Struts
In our Replacement shocks & struts section, you'll find factory-grade replacements that match the dimensions, longevity, and performance of your original equipment. Because we've grouped shocks and struts together here, entering your vehicle's year, make, and model into the top search box will show you the exact matches for the OE shocks or struts your vehicle was built with.
Performance Shock Absorbers and Struts
In our Performance shocks & struts section, you'll find a greater number of mono-tube and gas-charged shocks designed for firmer, more aggressive handling. Here, the compression and rebound settings of various shock absorbers make more of a difference.
Generally, firmer compression settings mean the piston inside the shock has greater resistance to moving downward and the ride will have less give. A firmer rebound setting translates to a shock absorber that will bounce back up less eagerly during its extension. For example, on the drag strip, you want the front end of a rear-wheel-drive car to quickly rise on takeoff then slowly drop to ensure more weight stays over the drive wheels for grip. For this particular application, best results would be with soft rebound (extension) settings and firm compression settings.
Performance Shocks for Off-Roading
Another Performance variation of shock absorbers are those with the capacity to carry more oil and nitrogen gas. This extra capacity takes the form of an additional fluid reservoir tube that's either attached or detached from the main shock tube. These are ideal for heavier vehicles used off-road which see huge amounts of wheel travel and hard impacts that would overheat standard shock absorbers.
The increased oil capacity keeps fluid temperatures low, and added gas volume allows compression and rebound valves to perform more consistently under the most severe conditions. Thus, an excessively bouncy ride that leads to dangerous handling can be avoided.
"Piggyback" style shocks are built with the reservoir canister mounted directly to the main shock absorber body, while true "remote reservoir" shocks have a separate reservoir (connected by a length of high-pressure hose) which can be mounted in another location on the vehicle frame. Performance of both styles is unaffected by how far away the reservoir is, and choosing between the two should be based on how much available space can be found under your vehicle.
Some examples of piggyback style shocks are the King Shocks OEM Performance Series Shocks and Pro Comp Black Series Shock Absorber, among others. When it comes to remote reservoirs, shocks such as the Fox 2.0 Performance Series Smooth Body Shock Absorber are set up with a separate tube that can be mounted further away.
Performance Long Distance Racing Shocks
Racing for long periods of time is a driving condition that makes it well worth your while to invest in high-performance mono-tube shocks. Brake rotors, pads, and calipers often reach 1,800 degrees Fahrenheit over the course of a circuit race, and that heat transfers directly to the nearby suspension components. And, that heat reaches shock absorbers too.
Because high temperatures have a direct effect on shock absorber performance, the benefits of mono-tube shocks really pay off on the racetrack. Their ability to dissipate heat more effectively and stay cooler keeps performance steadier, and lack of fluid aeration prevents squishy, unexpected surprises. The shorter stroke typical of mono-tube shocks won't be a problem on a smoothly-paved, flat track surface - especially if stiffer springs are installed on your race ride as well. If you're interested in seeing shocks that are more oriented towards racing, click here.
Danielle's 2000 BMW 3-series sedan was in fantastic shape, helped in part by residing in the warm and dry Southwest, so body corrosion was not an issue. At just over 100,000 miles, she was still cruising on the car's original springs and shocks, and although she didn't buy it new, she got it at 3 years old and with only 15,000 miles, so Dani was acutely aware of the deterioration in ride quality.
Danielle knew a year ago that it was time for replacement springs and shocks, and there was no delaying the purchase decision any longer. Her BMW used struts in the front, and separate springs and shocks in the rear, so she was keen to see what was available.
Checking out springs first, she saw that there wasn't a lot of choice on the repair side of the fence. The brand name Bilstein caught her eye, and looking at the choices for her particular model (328i sedan), a set of 4 Bilstein replacement springs would run a little over $150 before any tax and shipping.
On the performance side, the top-recommended brand, Eibach, had a set of 4 springs which would lower the car by 1.8" front and rear. These were $261 for the set, or about $110 more than the OE-style Bilsteins.
Dani wanted to look at shocks before making a final decision about springs. Similar to what she had found earlier, the Bilstein brand had a set of OE-quality struts (front) and shocks (rear) for her car. The front struts in this case did NOT include springs, so she would be free to choose her own. The 4 Bilstein shocks had a subtotal of $280.
She was pleasantly surprised at first to see that Bilstein also offered performance shocks, and the heavy-duty specs certainly made them desirable. However, as great as they sounded, the 4 shocks totaled over $1,100. If her car were newer and had fewer miles on it, it would have been a no-brainer. But in the end, given that she was planning to keep the car only for another 5 years/50,000 miles or so, she opted to stay with the stock Bilstein products.
Her happiest surprise? A complete new set of top-rated Bilstein brand springs AND shocks for well under $500. As far as Danielle was concerned, THAT was money well-spent.
To sum things up, if you're happy with the ride comfort, overall stability, and lifespan of your original equipment springs, shocks, and struts, you'll be pleased with the value and performance of our "repair" components - many of which provide an improvement over factory grade parts.
If you prefer to customize and spice things up a little with firmer handling, ride height changes, or trail readiness, you'll be satisfied with how a new set of Performance springs, shocks, and a few other small pieces will get you where you want to be.
To help make your shopping experience easier, we're glad to answer any questions you may have about shocks and springs. We've got knowledgeable product reps on call seven days a week that will be glad to listen and share any expert advice possible - without high-pressure sales tactics. We look forward to hearing from you!