Suspension springs improve ride comfort and safety by recompensing uneven road surfaces, thus ensuring that the road surface is safe for the wheels regardless of its condition. They are what link the vehicle to its wheels, and as such, must ensure that they always have even contact with the ground.
In modern vehicles, suspension springs facilitate optimal drive transmission and braking as well as functions reliant on transverse forces. As a result, the braking performance, the wheels’ ability to grip the road (road-holding), and the handling of a vehicle depends on good suspension.

Types of Suspension Springs

Design-wise, suspension springs can be categorised based on whether they have a linear or progressive spring rate. In the former type of spring, the extent to which the springs are squeezed is comparative to the amount of spring force released, so the harder they are squeezed, the more force they produce. Progressive springs are characterised by soft curves at the ends which gradually taper into harder, thicker coils.

Today, there are four commonly used types of suspension springs. They are:

Mini-Block Suspension Springs

Mini-block springs are an example of suspension springs made from tapered wire. These barrel-shaped springs produce a progressive spring rate and ends that are designed to prevent contact from winding to another.

The tapered ends rest on spring cups made from rubber blocks when squeezed together without the windings grinding into each other. This reduces the number of active windings, causing the spring rate to increase.

Cylindrical Suspension Springs

Traditionally, suspension springs were cylindrical and provided a linear spring rate. These are still common in today’s vehicles.

Inconstant Wire Suspension Springs

Inconstant wire suspension springs are made from wire with tapering ends. Their diameters increase towards the middle but reduce at the ends of the springs. These soft ends, during normal loads, are known to considerably improve ride comfort as well as reduce the load on the entire suspension system of the wheel. As a result, road holding, steering, and braking are improved.

Banana-Shaped Springs

These are side load springs that are primarily tasked with force distribution on the wheel suspension. They also improve the shock absorber’s response properties by minimising friction between the piston rod and gasket.

Constant Wire VS Inconstant Wire Suspension

One structural consideration creates a divide between the types of suspension springs out there. There are constant wire springs, which are manufactured using wire with the same diameter across the whole length of the spring, and there are inconstant wire springs, which have a wire diameter that varies across spring length.

In terms of ride variation, inconstant wire springs provide more options since they are considered to be two springs in one. Assuming low or optimal vehicle load, the low compression results in “soft” springs, but when the vehicle is at full load, these springs become stiffer. The progressively rising spring rate guarantees stable road holding irrespective of the vehicle’s load.

Inconstant wire springs also have the following advantages:

  • They eliminate the banging of springs under heavy load
  • When given the proper surface coating, they cannot be damaged easily

The Lifespan of Suspension Springs

Suspension springs from established manufacturers come with adequate protection from damage and corrosion. Today’s suspension springs are smoother and quieter as well as more resistant to rust thanks to the inclusion of plastic hoses at the ends of the springs. These plastic hoses also prevent surface damage.

Your vehicle’s suspension springs are designed to last at least its entire lifespan. You can ensure optimum performance by scheduling regular inspections during wheel changes and service work.

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Birmingham Springs combines technical knowledge and manufacturing experience. The team comprises engineers with backgrounds in Spring design and manufacture, process manufacturing and material science.