Since the very first horseless carriage was created, focus has been placed on creating a smooth ride. Imagine the first vehicle hitting a rock or a dip in the road – there wasn’t pavement back when the first vehicle was moving around.
Every bump moved from the wheels into the car, jostling the passengers around.
As more cars were built and sold, more time was spent on keeping the passengers safe, comfortable, and happy. Suspension systems are designed to provide each of these things and more.
What is a suspension system?
The suspension system includes all of the parts in the body of the car that allow it to connect with the road – wheels, tires, brakes – as well as the parts that help each of those systems operate – springs, shock absorbers, and other hardware. A suspension system is designed to support the weight of the vehicle, to absorb the shock that comes up into the vehicle with every bump and movement it makes, as well as provide a pivot point for the wheels. Its ultimate goal is to provide passengers with a smooth ride, while keeping you and the vehicle safe during the process.
A suspension system works to absorb the shock when you hit a bump, as well as to decrease the impact sent up through the axel and into the passenger section. The two are connected, yet through a variety of components, it’s designed to lessen the impact. How this occurs often determines the comfort level of the vehicle. This is where trucks and cars move apart.
Front end suspension systems
Most passenger cars and light trucks on the market today use a front suspension system. This includes a conventional coil spring, a Torsion Bar, and MacPherson Strut systems. You’ll find full-sized vehicles use a coil spring or the torsion bar systems frequently, while struts are more widely used on import vehicles and newer domestic vehicles.
No matter how it’s constructed, all suspension systems are designed for the same function – they support the vehicle to maintain proper wheel alignment, to connect with the road efficiently, and to absorb road shock as it moves up through the tires. How this is accomplished may change from system to system, but the final impact is always the same.
A coil spring system works by supporting the weight of the vehicle on coil springs and controlling impact by spring weight. The springs are mounted on either the upper or lower control arm, which also determines where the ball joint will be placed. The load-carrying ball joint is always on the same control arm with the spring.
With the torsion bar system, the vehicle’s weight is supported by the twisting of the bar. The torsion bar performs the same function from above as the coil spring in the vehicle.
With the MacPherson struts, the shock absorber, coil spring, and axis pivot have all been combined into one strut assembly. The weight of the vehicle is supported at the top of the spring plate, while the shock absorber dampens vibrations as the coil spring controls the ride.
Rear suspension systems
Most read wheel drive vehicles on the road today use a leaf spring and coil spring suspension.
They are designed with a solid axle that has some of the same characteristics as a solid axle front system. But the difference lies in movement – the rear wheels don’t pivot. Because more cars are coming with front wheel drive systems, you’ll also find more independent rear suspension systems. They offer improved performance and better control overall.
With a leaf spring system, the control arms are eliminated. A U-bolt connects the springs to the axle, which in turn connects the spring to the frame.
With a coil spring system, the coils sit on the axle housing on the underside of the vehicle. Movement is handled through control arms.
With an independent rear system, it’s used on a non-solid axle. This means that the vehicle will pivot independently based on suspension movement. This encourages better traction, since the wheels have flexibility in the angles they turn to as the wheels turn and move. This provides better acceleration and braking, and less resistance overall.
While independent systems provide better driving ability, it also adds more wearability to your vehicle. Because the wheels act independently of one another, each side must be aligned to the other, as well as to both front wheels. More parts, more servicing, which ultimately means more cost. But for increased safety, it’s worth the effort.
Car vs truck – what’s the difference?
Every car and truck is designed as the manufacturer chooses to produce it. Traditionally manufacturers used a leaf spring layout for the suspension system because they felt it was the safest for heavy loads. However, rules are always meant to be broken, and many have deviated and tried other things.
While most cars on the road today will use front and rear independent suspension systems for maximum control and comfort, many trucks also move to live axles placed at all four wheels.
It’s the shock absorbers’ job to control the axle’s motion as it takes in every bump in the road. For a truck, this task requires different degrees of control, which requires a heavier duty component the more weight you carry.
Trucks also have other considerations for the way they move. Many trucks need ground clearance and lift kits to ensure they navigate safely over rough roads. That means the suspension system must be longer to travel and up and down with every bump it takes in.
Off-road driving can also increase heat. The shock absorber must be able to dissipate that heat as it’s generated in each of the conditions you may put it through. From hauling to off-roading, the suspension system has to be ready for the job at hand.
When was the last time you had your suspension system thoroughly evaluated, to ensure your comfort and your safety? Suspension systems send out early warning signals about potential problems. Are you paying attention to what your vehicle is trying to tell you?