What is a Strut on a Car? | Shocks vs Struts

What is a Car Strut?

The struts are a structural component of most modern independent suspension systems and serve as a connection point between the wheel and the vehicle body. They are mounted at the top of the chassis at the front-end of most front-wheel-drive vehicles.

However, struts are not limited to front-wheel-drive configurations. The primary purpose of the struts is to support the weight of the vehicle while also absorbing surface impacts and ensuring a smooth ride.

A strut assembly consists of two primary elements: the coil spring, which supports the height, weight, and stability of the vehicle; and the shock absorber, which swallows bumps and dampens vibrations caused by irregularities on the roadway.

Other components of the strut geometry include the spring seats, the strut bearing, and the steering knuckle. Struts are typically installed in conjunction with the front wheels, but depending on a vehicle’s setup and driveline, they can also be mounted at the rear wheels. Just as there are different types of cars, there are different types of struts.

“Shocks” and “struts” are terms often used together or interchangeably, but that can create confusion. There are major differences between the two components. Shocks, by themselves, have one primary function – to absorb bumps at each wheel – but they are not essential in the operation of a car or truck. Struts, on the other hand, have multiple functions (including shock absorption) and are essential for vehicle operation. Struts allow control and maneuverability of the vehicle.

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When the struts are functioning properly, they will minimize the bounce a vehicle would otherwise undergo in normal driving. As a result, occupants experience a smoother and more level ride, free from most unwanted oscillations and jarring movements.

Struts are important to overall vehicle operation because they are integral to both the suspension and the steering systems. In addition to general ride quality and load-bearing support, they impact brake performance, wheel alignment, and turning ability.

Some vehicles utilize a strut tower brace, a rigid bar installed across the top of the chassis to increase a vehicle’s stiffness. This kind of reinforcement will enhance the vehicle’s overall dynamics, especially through high-speed handling maneuvers and cornering.

What Is A Strut On A Car

How do Shocks and Struts work?

Shocks and struts help stabilize your vehicle’s movements, enhancing control when you turn, brake, accelerate or encounter uneven road surfaces. Today’s vehicles use shocks, struts, or a combination of the two.

The basic difference is that a shock is an independent component, while the strut combines the shock and other features in a single structural unit. Both help to stabilize the vehicle and keep the tires in contact with the pavement. Without shocks, your vehicle would bounce down the road.

How long can you expect your shocks or struts to last? General strut replacement is recommended between 60,000 and 80,000 miles, but sooner if your vehicle regularly carries heavy loads or drives on unpaved road surfaces. These conditions can cause struts to wear more quickly.

Aside from mileage and harshness of use, there are numerous indicators that your struts may need replacement. These include any of the following symptoms: an overall harsh ride, a noticeable vibration after riding over a bump, dull or unresponsive steering, sudden tire tread wear, wheel wobble during braking, swaying or excessive body roll when making a turn, or any evidence of a hydraulic fluid leak beneath the tire well.

One simple test a car owner can perform is to push down on the hood of the vehicle by hand to see if it comes back up and settles immediately. If it oscillates more than twice before settling, the struts are likely not functioning optimally.

Are Shocks And Struts The Same Thing?

Shocks and struts are both parts of your vehicle’s suspension system. However, each one has a very specific job.

Struts vs Shocks

Shock absorbers are hydraulic components that help minimize movement generated by the vehicle’s springs. These springs absorb some of the jolts you might feel from uneven or damaged roads. By softening the impact from rough roads and rocky terrain, shocks can help you maintain better control over your vehicle, resulting in a smoother, more comfortable driving experience.

Struts are structural components of certain vehicles’ steering and suspension systems. They usually consist of a spring and a shock absorber. Struts are designed to be much stronger than shocks since they are weight-bearing components. Additionally, they help dampen vehicle jolts and improve your vehicle’s steering and alignment.

Do All Vehicles Have Struts?

Many vehicles will have shocks on one axle and struts on the other. However, not all vehicles have struts. Depending on its design, your vehicle might use separate springs and shocks in place of struts. If you’re not sure whether your vehicle has shocks or struts, there are a few ways you can find out.

Struts vs Shocks what’s the difference

The major difference between shocks and struts is that a strut is a structural part of the vehicle’s suspension system where a shock is not. A strut is also a crucial part of the vehicle’s steering system and greatly affects alignment angles.

Camber and caster angles are usually adjusted right on the strut itself. A strut is also a pivot point for the vehicle’s steering system and contains a coil spring. Because of this, an alignment is always needed when replacing a strut. This is also the reason that struts are typically more expensive than shocks.

A shock absorber on an automobile does one thing and one thing only keeps the car from bouncing. Struts are considerably different. Struts are a structural part of the suspension system and are mounted to the chassis of the vehicle on the top, and they come down through. 

They give us a place to mount the coil spring, and the spring is what maintains the height of the vehicle, so we have a plate in here for the spring. It also replaces the upper control arm and it connects directly to the knuckle on the car, which in many cases gives us a minor ability to adjust alignment.

Okay, so there is a big difference here, what’s the advantage? Well, shock absorbers usually give you better handling, while struts give you a lower initial cost for the vehicle.

Now if you want to check these, and they should be checked on a regular basis, you’re going to do two things; number one you’re going to bounce the vehicle up and down, and you do that over each wheel. Consider the normal state of rest and then you get it bouncing so that it bounces above and below the normal state of rest. 

You’re going to let go of it in the down position and it should come right back to the center and stop. If it continues to oscillate, the shock or strut on that corner of the vehicle is bad, and you always replace them in pairs, two fronts, or two rears.

The second thing you do is you raise the vehicle up and you look for any signs of oil leaking out of that shock or strut. If oil is leaking out it’s bad and again you replace the pair of them, the fronts or the rears.

But if you want to replace them yourself, the shock is not much of a problem. Just follow the directions that come with the shock absorber. But the strut, remember that spring? That thing could be very dangerous. 

Don’t just go un-bolting parts of the strut because you could be in for a nasty surprise when that spring takes off. To do a strut you have to have spring compressors such as we have mounted on this spring right here. This will compress the spring and give us the ability to handle it. You have to be careful with it because it’s still dangerous, but you should be able to change the struts yourself.

Does Your Vehicle Need New Shocks Or Struts?

Shocks and struts can wear out, especially if you do a lot of off-roading or drive on uneven or rough roads. It is recommended that you have your shocks and struts inspected after 50,000 miles or according to your vehicle manufacturer’s maintenance schedule. But if you’re unsure of the last time you had them inspected, here are a few signs to watch for to know whether it’s time to get them looked at:

  • Your vehicle sways noticeably when going around turns or changing lanes, making it hard to steer.
  • The front end of your car dips down when braking or the rear end dips down when accelerating.
  • Your tires wear or show abnormally flat areas (cupping)
  • Excessive vehicle bounce
  • Steering response is poor or you hear a noise when turning
  • Lack of control at high speed
  • How shocks affect braking infographic

While there are several telltale signs of shock and strut issues, some can be difficult to identify with confidence. For example, some signs of uneven tread wear can lead you to believe there is an issue with your shocks or struts, but these same symptoms can also point to wheel alignment issues, inflation problems, or a myriad of other conditions. That’s why it’s important to get a professional opinion before “self-diagnosing” your car.

Replacing old or worn-out shocks and struts isn’t just beneficial for your vehicle, it can also protect your investment in your tires by reducing unnecessary wear so you can get more life from them.

How Much Would It Cost to Replace Your Shocks and Struts?

A typical shock and strut replacement can set you back anywhere between $450 and $1,100 on parts and labor combined. An individual shock and strut assembly costs around $150 to $900, while estimated labor costs for replacing a shock and strut assembly can range anywhere from $150 to $300 per assembly. Keep in mind that prices may vary depending on your location and your type of vehicle suspension.

Drivers with extensive experience in DIY auto repair may save on labor costs by removing the old shocks and struts and installing the new ones themselves. However, if you lack the knowledge and tools for the job, it’s better to leave it to a professional.

Auto repair shops often have markups on the replacement parts they offer, while official dealerships use original equipment manufacturer (OEM) parts that cost even more. To save on costs, consider purchasing an aftermarket replacement online. They typically offer the same performance as the factory-issued parts, but for a more competitive price.