Whenever you drive over a pothole or speed bump, you'll be grateful that your vehicle has working shocks and struts. But while these two elements are frequently addressed as a unit, they are actually separate pieces that work together to make your vehicle stable and secure.
By the end of this article, you will understand:
- The differences between shocks and struts
- How they are similar
- What shocks and struts do
- How to know if your vehicle has shocks and struts
- When to replace them
- How much that replacement costs
What Do Shocks and Struts Have in Common?
Shocks and struts are both damping or shock-absorbing components that lesson the forces transmitted from the road to the vehicle. They are the primary elements that ensure you have a pleasant and comfortable journey.
Shocks and struts are important parts of your vehicle's suspension system and help to maintain a strong tire-road contact. This function affects the vehicle in several ways including:
- Prevention of abnormal body and tire motion.
- Better wheel alignment.
- Decreased rate of tyre and suspension wear.
- Steady braking and handling.
- Reduced vehicle spin and bounce.
What Are the Functions of Shocks and Struts?
The words shocks and struts are often used to mean the same thing. However, they are two different components with separate roles. Both parts improve the ride quality of your vehicle but in different ways. While shocks are single components, struts form a part of the chassis and suspension system.
The main job of a shock absorber is the control of spring and suspension motions. It does this by converting kinetic energy to heat energy which is then released through hydraulic fluid. Shock absorbers respond to changing road conditions and minimize bounce and vehicle spin, as well as dives and squats.
Struts, on the other hand, have two main roles. Like shock absorbers, they are involved in damping, creating resistance to the forces caused by up and down motion of your vehicle’s suspension. But unlike shocks, struts serve as a support structure for the vehicle’s suspension and the spring and help to keep the tyre in a balanced position. They also take the brunt of the vehicle's side loads.
How Do Shocks Differ From Struts?
A lot of people assume shocks and struts to be the same component because they are both involved in a singular function - damping. However, they are designed differently with each part having its own set of benefits and drawbacks.
Shock absorbers are very similar to oil pumps in that they absorb vibrations. Work is done against the hydraulic fluid in a pressure tube by a piston attached to the end of a piston rod. The fluid is pumped through orifices or holes inside the piston when the suspension moves up and down. However, only a small amount of fluid passes through these holes, which causes the piston to slow down, and subsequently delays the movement of the springs and suspension.
In contrast, struts are made up of a truss housing that supports the suspension system and a damping mechanism that controls the movement of springs and suspension within that housing. The bottom of most struts is connected to the wheel assembly, which is connected to a control arm through a lower ball joint.
A proper strut unit is a single, completely assembled item that has all the components required for strut replacement. It supports the vehicle's weight by combining the strut housing, damping unit, and coil spring.
How Can I Know If My Vehicle Has Shocks or Struts?
A lot of vehicles have shocks on one of the axles and struts on the other. However, you might not always find struts on your vehicle. Your car may have individual springs and shocks in place of struts, depending on its model. There are a few methods to determine whether your car is equipped with shocks or struts.
The easiest way is to look under your vehicle. If there are shocks installed in the vehicle, you'll see them behind the tyres. They are always mounted vertically and are often shaped like a spring or a pump. Struts, on the other hand, are positioned horizontally and look like a wheel extension. Because you may have both, you should inspect both the front and rear wheels of the vehicle.
Sometimes, the design may be different, and it'll be difficult to tell if your vehicle has shocks or struts. In that case, you can visit a technician to confirm.
When Does My Vehicle Need New Shocks or Struts?
Now that you know the functions of shocks and struts as well as their differences, it is necessary to understand when they should each be replaced.
You will notice a number of warning signs if these parts reach the end of their lives. If the need to replace your shocks and struts arrives, you will notice some or all of the following:
- Imbalance at high speeds: If you notice that your vehicle is never entirely steady or there's even a slight swaying of the vehicle on the motorway, it may be a sign that you need to replace the shocks and struts.
- Tilting: If your vehicle leans to one side when taking a bend, it is a sign that the shocks and struts are bad. It makes your vehicle very unsteady, especially in a sharp turn.
- Under heavy braking, the front end drops more than usual. It's possible you won't notice this until you have to slam on the brakes.
- Uneven tyre wear: The tread wears in a wavy pattern rather than uniformly because the tyre isn't properly attached to the road.
- Leaking fluid on the exterior of shocks or struts: This indicates a broken seal and loss of important internal fluids.
How Much Does it Cost to Replace Shocks and Struts?
Shocks and struts should last about 50,000 to 100,000 miles. However, this figure can be affected by certain factors such as frequency of use and the type of roads you drive on. During replacements, it is always advised that you change the shocks and struts on the same axle.
It is simpler and cheaper to replace shocks because there is no interference with the steering, caster angle, or camber. Also, a wheel alignment isn't necessary. Costs of replacing shocks on the same axle generally range from £190 to £450 for parts and between £75 and £200 for labour.
Struts, on the other hand, are more expensive. The price of changing a pair of struts including wheel alignment can be between £300 and £750. This is more expensive than a separate strut assembly which usually costs about £110 to £260 and an additional £75 to £225 per pair. You can also step down the cost by changing only the struts and not the complete assembly. However, this provides less value compared to replacing the entire assembly.
If you’re looking for a more accurate quote for your shocks and struts replacement, enter your vehicle reg and postcode into our online comparison site to find the best garage in your area. Compare labour costs, unfiltered reviews and ratings, distance and availability to save on your car maintenance with BookMyGarage.
Shock absorbers and struts are essential for making your vehicle travel smoothly and absorbing all of the shocks from speed bumps and uneven roads.
But while many people confuse shocks and struts, you must remember that they have differing roles and are made of different components.
Struts are similar to shock absorbers, but they also help with steering and offer structural support for the suspension.
You can read more of Lucas' articles on his website: off-roadinternational.com