What is a Rear Suspension in a Car?

[FernandoFitz]

Rear suspension in a car refers to all the force-transmitting connecting devices between the frame (or load-bearing body) and the axle (or wheels), and is one of the important parameters affecting the comfort of a vehicle. The car suspension system consists of three main parts: elastic elements, shock absorbers, and force-transmitting devices. Advantages of rear suspension in cars: Lightweight, reduces the impact on the body, and improves the ground adhesion of the wheels. Softer springs with lower stiffness can be used to enhance vehicle comfort; it allows the engine position to be lowered, thereby lowering the vehicle's center of gravity and improving driving stability. The three components of a car's suspension—elastic elements, shock absorbers, and force-transmitting devices—serve the functions of cushioning, damping, and force transmission, respectively. In passenger cars, elastic elements typically refer to coil springs, which only bear vertical loads and mitigate or suppress impacts from uneven road surfaces on the vehicle body. They offer advantages such as compact size, lightweight, and no need for lubrication, but lack friction and thus have no damping effect. Shock absorbers, usually hydraulic, are designed to quickly attenuate body vibrations and are the most precise and complex mechanical components in the suspension system. Force-transmitting devices include components like the upper and lower control arms (fork-shaped rigid frames) and steering knuckles, which transmit longitudinal forces, lateral forces, and moments, ensuring that the wheels have a defined relative motion pattern with respect to the frame (or body).

[MaryLynn]

The rear suspension of a car is the system that connects the rear part of the body to the two rear wheels, including components like springs, shock absorbers, and control arms. It primarily serves two purposes: cushioning road bumps for a more comfortable ride and keeping the tires firmly on the ground to enhance traction. For example, when going over speed bumps, the springs compress to absorb the impact, while the shock absorbers control the rebound, preventing rear passengers from bouncing violently. Additionally, during turns, it prevents excessive body roll, reducing the risk of skidding in wet conditions. Sedans often feature independent multi-link suspensions, allowing individual adjustment for each wheel, while off-road vehicles typically use solid axle setups to handle rough terrain. If this system fails, wheel alignment can go off, leading to uneven tire wear, and there's even a risk of axle detachment on rough roads.

[Irene]

The most direct experience of the rear suspension in daily driving is the difference in comfort. My car with a multi-link suspension barely feels small bumps, while my friend's car with a torsion beam at the same price can jolt the rear passengers to the point of discomfort on the same road. The structural difference lies in the independent suspension allowing the wheels on both sides to operate without affecting each other, so hitting a rock on one side won't disturb the other. During maintenance, special attention should be paid to issues like shock absorber leaks and aging or cracked rubber bushings. Once, my car's chassis made a clunking noise, and upon inspection, it was found that the suspension link ball joint had loosened. If not addressed promptly, the entire tire angle could become misaligned. When overloaded, the springs are prone to sagging, and prolonged deformation can affect the driving trajectory.

[LunaDella]

The type of rear suspension directly affects the driving experience when choosing a car. Budget commuter cars commonly use low-cost torsion beam suspensions, which are simple in structure but exhibit noticeable body roll during cornering. Performance-oriented vehicles are equipped with multi-link suspensions, which utilize five metal arms at different angles to precisely control wheel movement, resulting in much sharper steering. Off-road vehicles employ solid axle suspensions, where the two wheels are rigidly connected to withstand rough terrain. For daily driving, pay attention to three key aspects: abnormal tire wear indicates alignment issues, excessive body bounce over speed bumps suggests worn shock absorbers, and instability at high speeds may be caused by deformed control arms altering steering geometry. Simple suspension structures are cheaper to repair but offer limited performance, while complex structures are the opposite.

[LaJayce]

In auto repair shops, three common rear suspension issues are frequently encountered: Shock absorber oil leakage leads to failed vibration damping, making the car feel like riding a spring mattress over bumps; cracked rubber bushings cause metal parts to rub and create strange noises, with the chassis creaking as if it's falling apart; deformed control arms result in wheel toe-out, wearing out the edges of new tires in just 5,000 kilometers. Special attention should be paid to models with air suspension—leaking airbags can cause the rear end to sag and press against the tires. Daily prevention is simple: slow down over potholes to reduce impact, avoid overloading the trunk like a moving truck, and rinse off mud and dirt from the undercarriage during car washes to prevent rust. When issues arise, start by checking and replacing small components like ball joints and bushings—it’s much cheaper than a full suspension overhaul, saving you two to three thousand.