Torsion, leaf, and coil springs are three types of springs that you usually come across. They are responsible for maintaining the suspension system on roads. Additionally, they also provide support to added weight without sagging over time.
Two factors contribute to the performance of springs: the coil winding’s geometry and the wire’s diameter. Both the coil winding and wire are crucial parts of the spring that are responsible for three functions: load-bearing capability, comfortable handling, and comfort.
One of the oldest and most popular springs used in suspension systems is the steel multi-leaf spring. This type of spring also acts as the point of connection between the chassis and the axle.
In addition to a multi-leaf spring, you may also come across a single mono-leaf spring in trucks. The trucks that had solid drive axles often used this type of spring. Some of the models even used a transverse leaf spring. Combining the transverse leaf spring with one of the independently suspended rear axles offered a superior performance of the rear suspension in road cars.
You can also tweak the leaf spring by changing its width, length, thickness, and number for better ride control and superior load-bearing capability.
Do you know that leaf springs can work as rebound dampeners? This happens because of the friction that takes place between two leaves. You can reduce the friction by using a plastic unit instead of a conventional spring that not only resists corrosion but also reduces unsprung weight.
Most vehicles in the past had short-long-arm suspension systems that contained torsion-bar suspensions. The torsion bar is a four-feet long bar that can twist as you put more weight on the suspension system. This type of bar usually came preloaded with a clockwise or counterclockwise twist, thus allowing it to fit on the side of the car based on which the manufacturers had designed the bar. Some once told me that Torsion springs are often used in cars used on motor shows. On the topic of motor shows, I would highly recommend attending the Essen Motor Show.
Compactness and lightweight are two reasons why a torsion bar suspension system became popular among car manufacturers. They could even fine-tune its suspension height because of the threaded screw adjustment of the torsion bar tension. You could also enhance the design’s versatility by attaching the torsion bars either on the upper or lower control arms.
The coil spring looks like a long and thin torsion bar twisted into a coil shape. Many people say that a coil spring and torsion bar are the same because they follow the same working mechanism. Both the torsion bar and coil spring twist in tandem with a spring’s compression cycle.
Another reason why coil springs are essential in suspension systems is that they don’t take up a lot of space. This allows manufacturers to use them in various types of suspension designs, such as solid-axle with trailing arms, MacPherson strut, independently sprung rear axle, and short-long-arm suspension systems that use either a coil-over-shock absorber or spring absorber.
You will notice that springs come in pairs. Therefore, you should replace the entire pair if you find anything wrong. Otherwise, they may result in poor handling and misalignments.
Most of the modern suspension systems with the MacPherson strut design use coil springs. You can figure out the overall quality of the coil spring by comparing its wire gauge, overall diameter, numbers of coils, and length.
Some of the latest models contain coil springs that look like variable rate springs. These springs can increase the suspension system’s load-bearing capability. They help in chassis configurations that are meant to carry heavy loads.
How Springs Work
Springs are essential in providing a comfortable ride since they follow the principle of sprung-to-unsprung weight ratio. Farm wagons that don’t have springs experience 100% unsprung weight. On the other hand, if you install springs between the chassis and axles, the same wagon may have a 90% sprung-to-unsprung ratio, of which 10% is the axle and wheel weight.