What Is A Strut?

You may hear people mention the “strut” around the mechanic or the garage or even on the street. But do you really know what is a strut? How does it work and why does your car need it? So if you don’t, this article is exactly what you need. Let’s take a “strut” tour!

What Is A Strut?

So, what is a strut? Strut is a part of the car’s overall suspension system and holds the body of the car off the ground. Strut incorporates many suspension assembly parts,and the two main components are the coil spring and shock absorber, and affect your car’s steering and alignment. They provide support to the suspension springs. Their main job is ensuring the smooth ride, supporting the weight of the vehicle by acting as shock absorbers. 

what is a strut
Strut is a part of the car’s overall suspension system and holds the body of the car off the ground. Cre: Blue Fish Productions

The spring is always a coil spring which supports the weight of the vehicle and absorbs larger bumps.

The shock absorber, which is fitted either above, below, or right down the middle of the coil spring, also supports some or all of the vehicle’s weight but its main function is the same as that of any shock absorber. The shock absorber stops the vehicle from bouncing up and down after a bump.

Many people misunderstand the strut and the shock absorber. The shock only absorbs bumps on the road meanwhile the strut is much stronger than the shock absorber since it has the coil spring. 

Do All Vehicles Have Struts?

So you now know what is a strut, but is it correct that all of the vehicles use the struts and how many struts does a car have? The answer is no. Some vehicles use struts, some not. But they all have the shock absorbers. Some struts on a truck are only on the front wheels while the other pair employs a different design using separate springs and shocks but the left uses struts for the whole 4 wheels. When a car has struts on the front wheels only they are usually MacPherson struts, which are struts that are also considered part of the steering system because the wheels pivot around them.

But why do some vehicles use struts while others have separate springs and shocks? It is complicated to tell exactly the reason why. In general, it becauses most parts come down to a trade off between simplicity and initial cost and handling and performance. But for sport cars, they use double wishbone suspension which means they use shock absorbers more than struts. There are also exceptions for sports cars, for instance Porsche 911 uses struts.

Symptoms Of Bad Struts

By the time, the struts are wearing down and there are some symptoms which can be recognized if you are driving a car with bad struts.

1. Hydraulic fluid leak

If the struts are broken down, you will see hydraulic fluid leak out from one or more of the struts. The hydraulic fluid leaks out, the top of the struts will be wet. Because the oil often is not visible, your mechanic can spot leaks during an inspection.

how many struts does a car have
You will see hydraulic fluid leak out from one or more of the struts if the struts are broken. Source: MAC Hydraulics

2. Car bounce when hitting a bump

When you drive your car, your car hit a bump while driving. If the car continues to bounce and doesn’t settle quickly, it’s a sign the struts are wearing. A car that bottoms out is also a sign the struts may be wearing out. Bottoming out is caused when the coil springs are worn and allow the car to dip close to the ground or touch the ground after hitting a bump.

3. The tire

Tires wear or uneven wear is another sign of a bad strut. If the struts are wearing down, the back tires to sound like a basketball is being dribbled down the road while you drive. If you see this symptom in your car, check the struts immediately.


4. Rear end squat during acceleration

If you accelerate your car and you may notice that the front end of your vehicle rises while the rear squats. Your struts may be having problems.

5. Instability at highway speeds

Driving on highways or on high speed, your car never feels completely stable and it constantly moves up and down. It is the symptom of the bad struts.

struts on a truck
The car is not stable when running on the highway. Source: Chevrolet

How Often Do You Need To Replace The Struts?

According to some manufacturers, you should replace new struts around 100.000 miles – 200.000 miles. The quality of the struts are increasing gradually so some struts may last for 300.000 miles. To make sure your car has no problem when driving, it is recommended to replace new struts together with routine maintenance. But some professionals said you should replace only the old struts to prevent the high cost of replacement. It takes around $1200 for brand new ones and it’s actually a lot for routine maintenance. 

How Much Does It Cost To Replace Struts

When you find out what is a strut, then you should find out how much it is. It is important to buy good, high quality struts before replacing. Some may be a little stiffer for better cornering, while others may offer better ride comfort. Discuss your preferences with your auto professional before deciding.

To replace the new struts, It is important to you to take your car to the mechanics or trustful garage. They know what to do with your car. Since the price for the struts are different for each car maker, check the price before replacing. 

It is recommended to replace the whole set of struts which include coil spring and shock absorber for the safety and stability of the vehicle. When you take your car to the mechanic, ask them to check carefully not only the struts but also the other related parts such as bearing mounts, rubber bump stops and shock boots.. For example, if your passenger’s side strut is going out, replace both front struts to ensure that each side handles the same. Struts cost around $725 – $800 for itself, plus the repairing fee so it’s around $1000 to replace new struts.

Check out the video below to learn more how to replace the struts!

Final Words

So now you already know “what is a strut”, “how does it work”, “how often should you replace” and “how much does it cost”. The next step is taking a look at your car to check if your car has problems with struts or not. If you see the symptoms or you find that it’s difficult to realize, take your car to the mechanic or trustful garage. Replacing the struts is the only solution if your struts wear down. Keeping your car maintained also helps to find your car problem frequently, then the lifespan of your car is longer.