I spent most of my career in the automotive industry and road safety. I noticed that many car owners are confused about struts and shocks and use these two terms interchangeably.
In this article, I will help you have a clear understanding of struts and shocks. You will learn:
- What struts do?
- What shocks do?
- What are their main commonalities?
- What are their main differences?
3 Big Nuances
Your vehicle’s maker designed the suspension system based on either shocks or struts. Some cars have struts on the front axle and have shocks on the rear.
So, let’s clarify 3 big nuances.
- Each wheel will have either a shock or a strut, never both.
- You can not use a shock to replace a strut.
- You can not use a strut to replace a shock.
What Struts Do?
A strut groups several different suspension parts into one compact assembly. The main strut components are shock absorber, damping unit, coil spring, and mounts.
The primary job of struts on your car is to damp the springs’ movement and stop oscillations and bounces. The shock absorber part of the strut will compress and rebound itself while you drive.
The hard job of struts is to support and control your vehicle in motion.
The coil spring part of your strut can support and hold the weight of your vehicle. Otherwise, your car would be immobile.
Struts help in maintaining the height of your car.
Struts support the spring and hold the tire in an aligned position.
As a structural and integrated part of the suspension system, struts carry much of the sideload. The result is that struts affect your riding comfort, braking, steering, wheel alignment, and the wear on other suspension parts. 
What Shocks Do?
Shocks, or shock absorbers, are a crucial component of the suspension system. Without shocks, the wheels on your car will bounce and vibrate erratically down rough roads.
The main job of shocks is to control the impact and rebound movement of your car’s springs and suspension. Shocks ensure that your vehicle’s tires remain in contact with the road surface the long your ride.
The main parts of a shock are piston, coil, and hydraulic fluid—a fully integrated system to improve your ride quality and road safety.
If your car hits a pothole, the shock will initiate a compression cycle. The piston will apply pressure on the hydraulic fluid. The fluid will slow down the coil as it relaxes back into its place. As a result, the shock prevents an excessive bumpy feel and reduces bounce and roll or sway rate. Shock absorbers give you better handling. 
Struts vs Shocks
Both struts and shocks absorb energy from the suspension, which leads to keeping tires in contact with the ground, helping with steering and handling, making your ride more comfortable and your car safer. 
By their design, struts act as a structural part of the suspension. Shocks do not. Shocks are stand-alone components. Without shocks, you won’t have a comfortable ride, but your vehicle can still function. By the way, you should only drive a shock-less car in an emergency. Without struts, your vehicle would be immobile. 
Struts support the weight of your vehicle. Conventional shock absorbers do not.
Struts are more challenging to replace. Shocks can be relatively simple to change.
Struts are typically more expensive than shocks.
The Bottom Line
Most car owners use struts and shocks interchangeably. It’s a common mistake. Keep in mind that struts and shocks are two distinct parts.
Struts are a structural part of your car suspension system. Without struts, your car would be immobile.
Shocks are stand-alone components of your car suspension system. Without shocks, you won’t have a comfortable ride, but your vehicle can still function.
Struts and shocks have a primary common purpose: making your ride more comfortable and your car safer. So, it’s crucial to inspect regularly these suspension parts. Check out our article about the 9 signs when to replace shocks and struts.