MacPherson suspension: device, pros and cons

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

Suspension is one of the main mechanisms in the design of any vehicle. Thanks to it, the car is able to move on uneven sections of the road, reducing shocks and vibrations. Also, the suspension is the link between the wheels and the body. The system provides an elastic connection between these elements. Today there are several types of chassis. However, one of the most common is the MacPherson strut. The device, features, pros and cons of it will be considered in our today's article.

Characteristic

This system is the most popular for the front running gear of the car. It is used on all machines of the budget and middle class. The key feature of the MacPherson strut suspension is its compactness.

Thanks to this property, the system can be used on front-wheel drive vehicles and does not interfere with the transverse placement of the engine with the gearbox. Also, the features of many include simplicity of design and ease of maintenance. The MacPherson suspension itself is a continuation of the classic double wishbone chassis. However, in this case, the upper control arm has been replaced with a shock absorber strut.

Device

The design of this system includes the following elements:

• Hub.
• Brake disc with protective cover.
• Ball joint.
• Swivel arm.
• Helical spring.
• Lower and upper support cup.
• Thrust bearing.
• Stand cover.
• Compression buffer with support.
• Stock.
• Knuckle.
• Lower arm.
• Drive Shaft (Outer CV Joint).
• Hinge cover (is a rubber boot that is connected by clamps).

Next, consider the main structural components of MacPherson independent suspension.

Stretcher

This is the main carrier in the front undercarriage. The subframe is fixed by means of silent blocks to the car body. The use of such rubber-metal bearings makes it possible to reduce noise and vibration during the operation of the undercarriage. Some models require a rigid attachment of the subframe to the car body.

But regardless of the method of attachment, this element is also connected to the support of the transverse arm, steering gear and anti-roll bar.

Wishbones

These mechanismsattached to the subframe on both sides. Distinguish the transverse lever of the right and left wheels. The connection is made by means of rubber bushings, which also partially dampen vibrations and vibrations. The double fastening method serves to achieve greater rigidity of the structure in the longitudinal direction. Also, the transverse lever is connected to the steering knuckle (however, not directly, but through a ball joint).

Knuckle

There are only four of them. The fist stands on the right and on the left side, in the upper and lower parts. What is this item for? It is necessary for the wheel to turn. The fist at the top is fixed to the rack with a clamp connection.

At the bottom, the element is attached with a transverse lever (as we said earlier, by means of a ball joint). Also in the fist is a brake caliper and bearing assembly. The latter assumes the presence of a hub along with a needle bearing.

Shock absorber strut

It acts as an elastic element. Consists of two parts:

• Shock Absorber.
• Helical spring.

The latter is coaxial with the shock absorber and mounted on the rack. In order to change the elasticity characteristics of the spring, a compression buffer is also set here. At the bottom, the suspension strut is connected to the steering knuckle. At the top, it is attached to one of the power parts of the body, namely to the engine mudguard.

Anti-roll bar

Is an integral part of the MacPherson strut front suspension. Serves thiselement to reduce lateral rolls when cornering at speed. The stabilizer is made of elastic grades of steel and is fixed with two supports on the subframe. The ends have connecting rods with articulated ends.

Pros of MacPherson suspension

As we said earlier, this system has small dimensions. From this it is worth concluding that the mass of such a suspension is many times less than that of any other. Thus, it is ideal for small cars. The low weight of the system has a positive effect on reducing fuel consumption.

More MacPherson suspension has a large margin of safety. She's pretty reliable. There are not so many connecting sections and structural elements. Thanks to the attachment to the mudguards and the presence of a stabilizer, the system reduces lateral and longitudinal rolls. The next plus is the low cost and ease of installation. In view of this, the price of the car itself is significantly reduced.

The indisputable advantage of such a pendant is the large resource of its elements. So, the most "tenacious" on our roads are levers. They can walk up to 200 thousand kilometers. And you can only replace the silent block (although on some models the lever changes along with the rubber bushing). Wheel bearings and ball bearings have a resource of 80 thousand kilometers. The rack can walk up to 120 thousand or more. In terms of repair costs, this suspension is very cheap. Many parts can be replaced with your own hands.

Another plus is the possibility of self-diagnosis. Bycharacteristic rumble when cornering, you can determine that the hub bearing has failed. A crunch when turning indicates a failure of the strut support bearing. And deaf knocks and buildup of the body at speed indicate the wear of the shock absorber. The backlash of parts can be checked independently using a mount, having an inspection hole available.

Cons

But not everything is as smooth as it seems at first glance. This suspension is not used on all cars without exception, and for good reason. The first is cinematics. The suspension strut has a large travel and articulated mount. Because of this, the angle of inclination of the wheels relative to the vertical plane changes significantly. Because of this, MacPherson strut suspension is not used on sports and premium cars. Large travel results in insufficient wheel contact with the road and loss of control at high speeds.

Also, all loads (shocks and vibrations) are transferred directly to the body. These loads are especially amplified when driving on rough roads. Because of this, over time, the strut mount with the body mudguard is destroyed. Cracks appear in certain places. Spoils the picture is the fact that most of the suspension struts are non-separable. Therefore, in the event of a shock absorber failure, you need to buy a completely new rack.

But in most cases, manufacturers refuse such a suspension due to the fact that it does not have a high smoothness. No matter how soft shock absorbers are here, the MacPherson strut suspension will always be stiffer than a multi-link. Also this chassis is very noisy. Therefore, such a system cannot be found on business-class machines and above.

Summing up

So, we found out what the MacPherson strut has the pros and cons, and also examined its device. As you can see, this system is not suitable for all cars. It has certain limitations, and therefore is used mainly on cheap front-wheel drive cars. At the same time, you should not refuse to buy a car with such a chassis. After all, it will be much cheaper to maintain.