From absorbing road imperfections to keeping the tires glued to the road, your car’s suspension works overtime for a smooth, comfortable and controlled ride. The suspension is a collection of different car parts connecting the wheels to the car frame and chassis. While smoothing out potholes is one of its main purposes, the suspension also makes basic manoeuvres like braking, accelerating and turning possible ensuring a higher degree of safety and control.

What Suspension Systems Do

Despite the wide variety of car suspension systems found in different vehicles, all suspension setups aim to isolate the cabin from the road. This is what car manufacturers term ride quality. Different parts work together to dissipate the external forces that vehicles face when road surfaces change. They do this by converting these forces into heat and absorbing road irregularities, shocks, and vibrations along the way.

Safety and stability are often overlooked components. Suspension parts aim to keep the car level at all times, and prevent instances of excessive body roll in high-speed turns, or pronounced front-end diving during hard braking. Much of this is down to how the parts straddling each wheel deal with weight distribution, with different setups getting widely different results.

Common Parts

While setups vary in different vehicles, all suspension systems consist of several basic components:

• Springs – steel coil springs (one per wheel) are found in most passenger cars. At the rear axle of trucks and commercial vehicles, leaf springs, consisting of layered metal bars are tasked to absorb road irregularities, while torsion bars connecting the chassis and parts like wishbones do the same task in budget cars. Newer additions are air springs, or pressurized bags that can be inflated or deflated to lift or lower the chassis above each wheel.
• Shock absorbers – springs compress and absorb energy, but struggle when releasing it, leading to unwanted bouncing. Shock absorbers or dampeners step in to absorb or dampen the movement of springs as they return to their original position, offering more control and ride comfort. The parts do this by turning vibrations into heat, which is then dissipated through hydraulic fluid housed in metal reservoirs. Depending on the design of the reservoir casings, shocks come in monotube or twin-tube types, with significant differences in performance and price. Choose monotubes for improved road holding but a stiffer ride at higher speeds, or twin-tube shocks if comfort and daily tasks are a priority.
• Linkages – these are parts that connect the chassis and suspension and control movement. Common parts include upper and lower control arms, compressions or tension arms, radius arms, lateral links, trailing arms, and track bars.
• Pivot points – these connect linkages, provide structural support and allow vehicle control. Parts include ball joints, strut mounts, and bushings. They also help with dampening.
• Knuckles and spindles – these connect the steering to the suspension, ensuring steering input even when hitting potholes or road obstacles.

Variations and different combinations of the parts listed above lead to several types of car suspension systems.

Suspension Types

Components can be grouped into three main suspension types: dependent, independent, and semi-dependent.

Dependent Suspension

This consists of solid axles or beams connecting both wheels. Dependent suspension is more common in heavy vehicles and the rear axle in entry-level cars. It’s durable, dependable, and can handle more weight. Where it fails is the limited wheel articulation, with road imperfections affecting both wheels, resulting in a harsher ride.

Independent

This type of vehicle suspension consists of parts that allow wheels to move independently of each other. The result is improved comfort, better handling and more grip. There are several types. Macpherson struts are seen on the front axles of many passenger cars, with struts and springs in a single, more compact assembly, pivoting on an upper strut mount and a lower ball joint.

The setup is good for everyday driving, with decent handling, low maintenance needs and economical layouts. Performance variants include double wishbone setups with upper and lower control arms in varying lengths and multi-link suspension with multiple pivot points for improved handling and ride comfort.

Semi-independent

Semi-independent or hybrid setups are a mix of parts found in dependent and independent suspension types. A good example is the Macpherson strut on the front axle and a torsion beam at the rear. A setup that reduces costs in everyday cars while still providing a good balance of comfort, performance and handling.

Common Issues

While durable and reliable, suspension parts are put through their paces daily. This leads to gradual wear and telltale signs that parts need replacing. Consider a visit to your mechanic if you notice one or more of the following:

• The vehicle pulls left or right – This can be from worn ball joints, damaged bearings, hardened bushings or springs, shocks and control arms that have seen better days. To pinpoint the exact problem, have the suspension inspected to rule out minor related issues like tire wear and misalignment.
• Excessive diving, body roll or squatting – Cars that dive on braking, lean to sides in turns, or squat when accelerating need to be checked for problems with the shocks or struts. Here, oil leaks, corrosion and metal fatigue are the main causes of advanced wear and compromised handling.
• Tilting – One corner of the vehicle sitting lower often points to damaged springs. The addition of knocking or creaking sounds means springs are bottoming out and hitting bushes and mounts.
• Steering issues – Since the suspension and steering systems are connected, a problem in one quickly leads to a problem in the other. Inspect for damage in the control arms, ball joints and knuckles to ensure safety and prevent higher repair costs later on.
• Harshness and vibrations – Feeling every pothole the car passes? Bouncing, harshness and unsettling vibrations are not only uncomfortable but worrying signs of oil leaks in shocks, or damage to pivot points.

Maintenance and Replacement Tips

To maintain peak car performance and ensure the suspension smooths out rough roads, stick to regular inspections, routinely check pressure and ensure that the wheels and tires are aligned.

Routine annual checkups catch minor issues on time. Inspect the shocks for oil leaks, the springs for rust and material damage, and defects or wear in linkages, pivot points and steering components. Also, look for uneven tire wear and ensure tires are inflated to the recommended pressure.

For steering and handling problems, check if the wheels are aligned. Keeping the car clear of mud, dust and water reduces the likelihood of rust and wear. Moreover, changing driving habits to avoid abrupt acceleration, hard braking or driving over potholes spares parts and increases longevity.

For defective components, a safer bet is a working replacement. Car owners can choose original equipment parts with the same factory spec as new vehicles, or go for improved performance, better builds, and adjustability options in specialist suspension brands. Examples include the uptake in air suspension, coilovers and lowering springs that help with ride comfort, offer more vehicle composure in spirited driving and improve looks in tuned and custom cars.