Suspension Systems for 4WDs
A car suspension system is made up of many components that assist in dampening the undesirable effects of a bumpy road. The best part about a good suspension system for 4WDs in particular is that you can get a far smoother ride without compromising the road response, steering or braking of the vehicle. Unfortunately, not all 4WDs come equipped with the suspension you’ll need if you’re planning on doing any of the epic off-roading you’ll find in the outback, so you may want to talk to your mechanic about the various suspension options that are available.
The leaf spring, which is the original and most simple suspension system, is mainly used on modern utes and load-carrying vehicles and serves two main purposes: to locate the axle and provide suspension. In this system, both ends of the spring’s length are attached to the chassis with a bush and through-bolt, with the spring passing under the axle. Leaf springs are made up of multiple leaves, which slide against each other as the spring flexes, and there are three main types: quarter-elliptical, semi-elliptical and parabolic.
The best parts about this system are that you can use lead springs that have been designed to bear a particular load, the design is simple and less expensive than others, and the friction of the leaves stops the spring from bouncing out of control. The only major disadvantage is that, as the springs get older and rustier, they become quite stiff.
A coil spring is essentially a torsion bar, and works by storing energy when it gets pushed down. You can also fit your vehicle with independent coil suspension, which means each side of the vehicle can react to road undulations without affecting the other. This feature is why coil suspension is a favourite among off-road drivers who plan on driving on very uneven, punishing terrain.
The other major advantage is that coil springs don’t suffer from friction losses in the same way leaf springs do, so you can always expect a smooth and predictable suspension system. To make your system even better, use coil springs in conjunction with a telescopic shock absorber to give your vehicle greater suspension and better clearance in true off-road conditions.
With an air spring attached to a compressor, you will get a rising-rate spring with a high level of adjustability. The way it works is that air can be pumped into the spring or released in order to help keep the vehicle level depending on the driving conditions. The air system is generally electronic, and can also monitor the load, provide automatic traction control, and pre-set levels automatically.
The major advantage that this brings to serious off-roaders is that you can raise or lower the suspension at will. For example, you can raise the suspension when driving on uneven and bumpy tracks, and then lower it for when you’re on sealed road. On more sophisticated systems, such as on the latest Range Rover, you can raise or lower each corner of the vehicle individually for maximum effectiveness over rough terrain.
While there are many different types of suspension for 4WD vehicles, these are the most common. If you need something more specific, then it’s recommended you talk to your mechanic to outfit your vehicle to suit your needs.