Coilover Terminology Explained
You are looking at coilover kits online. You see words like spring rate, rebound, preload, monotube, pillowball. Some of it makes sense. Some of it does not. Before you spend real money on a suspension upgrade, you want to know exactly what these terms mean and why they matter.
This is the glossary. Every term you will hit when shopping, installing, or tuning coilovers, explained clearly. No fluff.
Understanding Coilovers
What Is a Coilover?
A coilover is a suspension unit that combines a coil spring and shock absorber into one integrated assembly. The name comes from the spring being coiled over the shock. That single unit replaces your factory spring and shock. It mounts between the chassis and the wheel hub. It gives you adjustable control over ride height, damping, and spring preload.
A quality coilover kit is the foundation of any serious performance suspension upgrade. That is the reason tuners, track drivers, and enthusiasts who care about how their car handles pick them over lowering springs or factory replacement shocks.
Key Components of Coilovers
Coil Spring. Supports the weight of the car and absorbs road impacts. Spring rate determines stiffness, measured in pounds per inch (lb/in) or kilograms per millimeter (kg/mm). Higher spring rate means stiffer, more performance behavior. Lower spring rate means more compliance and comfort.
Shock Absorber (Damper). Controls how the spring moves. Without a damper, the spring would bounce forever after a hit. Inside the damper, a piston moves through hydraulic oil, creating resistance that controls the speed of compression and rebound.
Threaded Body. The outer sleeve of the shock is threaded, allowing the spring perch to move up or down. Thread the perch down and the car drops. Thread it up and it rises. This is how ride height is adjusted.
Locking Collar. A threaded ring that locks the spring perch in place. Always torque it properly. A loose collar is how ride height changes on its own.
Upper Mount (Top Hat). Connects the coilover to the chassis. Rubber top mounts absorb vibration, quieter for daily drivers. Pillowball top mounts are more precise and allow camber adjustment but transmit more road noise.
Bump Stop. A rubber or polyurethane buffer at the top of shock travel. Prevents the damper from bottoming out during hard compression. On a well-set coilover you rarely contact it. When you do, you want it there.
Bushing. Flexible inserts at the mounting points. Rubber bushings absorb noise and vibration. Polyurethane bushings are stiffer, reduce flex, and sharpen steering response at the cost of more road noise.
How Coilovers Work
The coil spring and damper work together on every road input. When your wheel hits a bump, the spring compresses to absorb the impact. The damper controls how fast that compression happens and how quickly the spring recovers. Tune both correctly and you get a car that handles bumps without drama and corners without excessive body roll.
The threaded body and locking collar let you set ride height independently of spring behavior. That is the key advantage over lowering springs. You are not stuck at whatever height the spring puts you at.
Common Coilover Adjustments
Ride Height
Adjusted by moving the spring perch up or down the threaded body. Most kits allow 1 to 3 inches of drop from stock. Always get a professional alignment after any ride height change. It affects camber and toe.
Spring Preload
The initial compression applied to the coil spring before any weight is on it. Affects how the spring behaves at the beginning of its travel. On kits with separate preload adjustment, you set your stance without changing spring behavior.
Damping Adjustment
Controls hydraulic resistance inside the shock. More damping means firmer, more controlled movement. Less means softer, more compliant movement. Single-adjustable coilovers give you one knob. Double-adjustable coilovers separate compression from rebound.
Camber Adjustment
Available on kits with camber plates or adjustable upper mounts. Negative camber (top of tire leaning in) improves cornering grip. Too much wears the inside edge of your tires.
Monotube vs Twin-Tube Coilovers
Monotube. Single cylinder design. One piston and rod assembly moves through hydraulic oil. Oil and gas are separated by a floating piston. Faster response to small road inputs, better heat dissipation under hard driving. Preferred for track and performance use.
Twin-Tube. Inner and outer cylinder design. Inner cylinder houses the piston. Outer cylinder acts as an oil reservoir. More suspension stroke for a given length, smoother overall ride quality. Better suited to street and daily driver use. Generally more affordable.
Monotube. Single cylinder design. One piston and rod assembly moves through hydraulic oil. Oil and gas stay separated by a floating piston. Faster response to small road inputs. Better heat dissipation under hard driving. Preferred for track and performance use.
Types of Coilovers
Full Coilovers
Full coilovers replace your entire factory suspension with a matched spring and damper unit. This is the category we sell at coilovers.com, and the one that gives you the full range of flexibility. Ride height, spring preload, damping, and on many kits, separate compression and rebound control.
Slip-On Coilovers
Slip-on or sleeve-type coilovers slide over your existing factory shock. More affordable, but you are stuck with the damping performance of your OEM shock. A modest drop is achievable. Meaningful performance improvement is not. For anyone serious about handling, a full coilover kit is the right call.
Coilover Features and Benefits
Performance Improvements
Coilovers reduce unsprung weight by combining the spring and shock into one compact unit. Less unsprung weight means faster suspension response and better tire contact. On a track, that translates into more grip and better lap times. On the street, the car feels more alive and more connected.
Adjustable damping lets you manage weight transfer under braking, acceleration, and cornering. A properly dialed coilover setup reduces body roll, sharpens turn-in, and gives you more confidence at the limit.
Handling Characteristics
Spring rate determines how the car responds to body roll and road inputs. Higher spring rates reduce roll and sharpen handling at the cost of ride comfort. Lower spring rates improve compliance over rough roads at the cost of some body control.
Damping rate determines how quickly the suspension moves. Match your damping to your spring rate and your driving conditions and the car handles the way you expect. Mismatch them and you get either a bouncy, uncontrolled feel or a harsh, jarring ride.
Choosing the Right Coilovers
Use Case
Daily driver, track day, canyon road, or all of the above? A kit tuned for track use will be uncomfortable on rough city streets. A comfort-focused street kit will feel soft on a circuit. Most buyers want something in the middle, and that is the conversation we have on the phone every day.
Budget
BC Racing is our most popular kit, proven on thousands of builds. KW Suspension is the step up for premium German engineering. Fortune Auto is for serious tuners who want a rebuildable, fully customizable kit. Ohlins is the top of the range, motorsport heritage with the best ride quality at any price.
Platform
Every platform has different suspension geometry. Every brand we stock engineers vehicle-specific kits. A kit designed for your exact car will always outperform a universal kit adapted to fit.
Installation and Maintenance Tips
Install on a level surface with the car fully supported on jack stands. Torque every fastener to spec. Locking collars, top mount nuts, lower mount bolts. All of it. Get a professional alignment after installation. This is not optional.
Inspect your coilovers regularly. Check for fluid leaks at the shock shaft. Look for cracked boots or worn bushings. Confirm the locking collars have not loosened. Clean the threads every season. In salt belt states, apply anti-seize before winter.
Frequently Asked Questions
What is a coilover and how does it improve my car's suspension?
A coilover combines a coil spring and shock absorber into one adjustable unit. It replaces your factory suspension and gives you control over ride height, damping, and spring preload. The result is better handling, a lower center of gravity, and a setup tuned for how you actually drive.
What are the main adjustments available with coilovers?
Ride height via the threaded spring perch and locking collar. Damping via the adjuster knob. Single-adjustable kits give you one control. Double-adjustable kits separate compression from rebound. Spring preload on kits with separate adjustment. Camber on kits with camber plates or adjustable upper mounts.
What is the difference between monotube and twin-tube coilovers?
Monotube uses a single cylinder with faster, more sensitive response and better heat management. Preferred for performance and track use. Twin-tube uses inner and outer cylinders for more suspension stroke and smoother ride quality. Better for street and daily driving.
How do I know which coilovers are right for my car?
Think about how you use the car and what your budget is. Then call us. That five-minute conversation has saved a lot of people from buying the wrong kit. We know these brands, and we know which ones work best on which platforms.
Can I install coilovers myself or should I use a professional?
Mechanically inclined drivers with the right tools can do it. You need a floor jack and stands, a torque wrench, a spring compressor, and alignment equipment. The alignment after installation must still be done by a shop regardless. If you are not comfortable with suspension work, professional installation is the safer path.
What are the benefits of using coilovers over traditional suspension?
Adjustable ride height you can change any time. Better handling from reduced unsprung weight and a lower center of gravity. Damping you can tune to your driving style. The ability to corner balance. A coilover kit that works for you specifically, not the statistical average of every buyer. Know the Terms. Now Find the Right Kit. You know what spring rate means. You know the difference between monotube and twin-tube. You know what damping does. Now the real question is which specific kit is right for your car, your budget, and how you drive it. That is the conversation we have with customers every day. We know these brands inside out. BC Racing, KW, Fortune Auto, Ohlins, Feal, Tein. We know the platforms. Tell us what you drive and what you are trying to do. We will point you at the right kit. No runaround, no upsell. Just a straight answer from someone who genuinely cares whether your car ends up dialed correctly. 1-800-460-9106 Browse Coilover Kits
Know the Terms. Now Find the Right Kit.
You know what spring rate means. You know the difference between monotube and twin-tube. You know what damping does. Now the question is which specific kit is right for your car, your budget, and how you actually drive it.
That is exactly the conversation we have with customers every day. We know these brands inside out, BC Racing, KW, Fortune Auto, Ohlins, Feal, Tein, and we know the platforms. Tell us what you drive and what you are trying to do. We will point you at the right kit. No runaround, no upsell. Just a straight answer from someone who genuinely cares whether your car ends up dialed correctly.
1-800-460-9106Browse Kits by Your Vehicle