Strut vs Shock vs Coilover

Navigating suspension terms like strut, shock, and coilover can be tricky. Understanding their differences is key to knowing what your car has and what you might need.

Shocks are dampers, struts are structural suspension components that include damping, and coilovers are assemblies combining a coil spring over a shock or strut. Each plays a distinct role in your vehicle’s ride and handling.

When it comes to your vehicle’s suspension, terms like "shock absorber," "strut," and "coilover" are often used, sometimes interchangeably, but they refer to distinct components with specific functions. As a manufacturer and supplier of a comprehensive range of automotive chassis products, including shock absorbers and components for strut assemblies since 1998, we at GSW Autoparts believe it’s important for vehicle owners to understand these differences. This guide will help clarify what each component is and how it contributes to your car’s performance.

What is the difference between coilovers and shocks and struts?

These three terms are central to suspension discussions, but how do they truly differ in form and function? Let’s break them down individually.

Shocks are purely damping devices. Struts are structural suspension units that include a damper and support vehicle weight. Coilovers are assemblies of a coil spring mounted over a shock absorber or strut body.

Understanding these three is easier if we look at their primary roles. At GSW Autoparts, we deal with all these configurations:

• Shock Absorber¹ (or "Shock"): Its sole purpose is to dampen or control the oscillation (bouncing) of your vehicle’s springs. When your car hits a bump, the spring compresses and rebounds. Without a shock absorber, the spring would continue to bounce for a long time. The shock absorber converts this kinetic energy from spring movement into heat energy, thus settling the suspension quickly. It does not support any of the vehicle’s weight.
• Strut²: A strut is a much more significant structural component of the suspension, typically found in MacPherson strut systems, common in many front-wheel-drive cars. Like a shock, a strut contains a damping mechanism internally to control spring oscillation. However, a strut also provides structural support for the vehicle’s suspension, supports the vehicle’s weight (as the coil spring usually sits on a perch attached to the strut body), and often serves as the pivot point for steering by connecting directly to the steering knuckle. It effectively replaces an upper control arm in some designs.
• Coilover³: This term is a contraction of "coil spring over shock absorber." It describes an assembly where the coil spring is integrated with, and mounted directly onto the body of, a shock absorber or a strut. So, technically, a complete strut assembly (with its spring) is a type of coilover. However, in common aftermarket parlance, "coilover" often refers to adjustable performance units where you can change ride height and sometimes damping stiffness.

Do coilovers ride better than struts?

When considering an upgrade, many wonder if aftermarket coilovers provide a superior ride compared to standard factory struts. The answer depends on your definition of "better."

Coilovers don’t inherently offer a "better" ride for comfort than OEM struts; aftermarket performance coilovers often prioritize handling, which can mean a firmer ride. However, high-quality adjustable coilovers can be tuned for a balance of comfort and performance.

This is a frequent question we hear at GSW Autoparts. Standard Original Equipment Manufacturer (OEM) struts are engineered by car companies to provide a specific balance of ride comfort, handling, and durability suited for the average driver and everyday road conditions. They are generally tuned to absorb bumps well and provide a relatively compliant ride.
Aftermarket coilovers, especially those marketed for performance, often feature stiffer spring rates and more aggressive damping characteristics. The primary goal here is usually to improve handling, reduce body roll, and provide a more connected feel to the road. This often translates to a firmer, sometimes harsher, ride⁴ compared to stock struts. However, many premium coilovers offer adjustable damping⁵ (allowing you to make the ride softer or stiffer) and ride height adjustment. With these, you can potentially find a setting that offers better handling than stock struts without an overly punishing ride, or even tune for more comfort than a very basic, non-adjustable performance coilover.

I’ve seen customers install aggressive coilovers and love the handling but find the ride too stiff for daily use, while others find a well-tuned adjustable coilover to be a perfect compromise. So, "better" is subjective; for pure comfort, OEM struts are often superior. For enhanced handling and adjustability, quality coilovers can be a great upgrade, but choose wisely based on your priorities.

Is a strut and shock the same thing?

This is a very common point of confusion. Are "strut" and "shock" just different words for the same part? Absolutely not.

No, a strut and a shock absorber are not the same thing, although a strut assembly contains a damping mechanism similar to a shock absorber. A shock is only a damper, while a strut is a structural part of the suspension that also supports vehicle weight.

Let’s make this crystal clear, as it’s fundamental to understanding your suspension, something we emphasize at GSW Autoparts.
A shock absorber is purely a velocity-sensitive hydraulic damping device. Its job is to control the speed at which your suspension compresses and rebounds. If you were to remove a shock absorber from a vehicle (that doesn’t use struts), the car would still be supported by its springs, but it would bounce uncontrollably after hitting a bump.
A strut, on the other hand, is a major structural component of the suspension and chassis. It performs the damping function of a shock absorber (an internal damper is built into its housing) but does much more. A strut assembly (which includes the strut housing, damper, spring, and top mount) also:

1. Supports the vehicle’s weight (via the coil spring mounted on it).
2. Acts as a pivot point for steering (the steering knuckle is usually attached directly to the strut housing).
3. Often locates the wheel assembly, replacing the need for an upper control arm in many designs.
   If you remove a strut from a vehicle, that corner of the suspension would likely collapse because the strut is a critical load-bearing member. Think of it this way: a shock absorber helps control movement, while a strut provides support and control.

What’s better, coilovers or air shocks?

When considering suspension upgrades, particularly for adjustability, the choice between traditional coilovers and air shocks (air suspension) often comes up.

"Better" between coilovers and air shocks depends on the desired outcome. Air shocks offer superior ride comfort and on-the-fly height adjustment, while performance coilovers typically provide more precise handling and consistent spring rates for aggressive driving.

This comparison involves two distinct technologies for managing a vehicle’s suspension. As GSW Autoparts supplies components supporting various systems, we see the pros and cons of each.

• Coilovers (Traditional Coil Spring): As we’ve discussed, these use a steel coil spring over a damper.
  • Pros: Generally offer a more direct road feel, consistent spring rates (good for performance driving), wide range of spring rates and damping adjustments available for tuning, often more robust for track or aggressive off-road use.
  • Cons: Ride height adjustment is usually manual (requiring tools), can be stiffer than desired for daily comfort if aggressively tuned.
• Air Shocks / Air Suspension: These systems use air-filled rubber bags (air springs) in place of, or sometimes in addition to, metal coil springs. The "air shock" component itself still provides damping.
  • Pros: Can provide an exceptionally comfortable and plush ride, easily adjustable ride height (often with in-cabin controls or even automatically), ability to adjust spring rate by changing air pressure, good for load leveling in trucks or achieving a very low stance for show cars.
  • Cons: More complex system (requiring an air compressor, tank, lines, valves, and controller), potentially higher initial cost and maintenance, can sometimes feel less direct or responsive than coilovers in extreme performance driving scenarios, though modern systems are very advanced.

Which is "better"? For maximum ride comfort and convenient height adjustment (e.g., luxury sedans, show cars, or vehicles that need to adapt to varying loads), air suspension is often preferred. For dedicated track cars, serious off-road racing, or enthusiasts prioritizing raw handling feedback and mechanical simplicity, high-performance coilovers are typically the go-to.

Conclusion

Shocks, struts, and coilovers each serve vital, distinct roles in your vehicle’s suspension. Understanding these differences helps you maintain your car properly and make informed upgrade decisions.