The suspension is one of the most overlooked parts of tuning vehicles. Often times, people who’re looking to prepare their 4WD for the off-road think that buying a great set of coil overs means they’re off-road ready. But that can’t be further from the truth. In reality, picking the right 4WD suspension upgrades is similar to choosing the right shoes. You wouldn’t wear Jordans to jog around the neighbourhood, just like you wouldn’t wear Air Max for a pickup game. While you technically can jog in Jordans and play ball in Air Max, they’re really not the best-suited footwear for the occasion. So what do people mean when they talk about suspension?
Most people refer to springs and shocks as suspension. But ‘suspension’ is the term given to the system of shocks, springs and linkages that connect the vehicle to the wheels. Original equipment manufacturers (OEM) take a wide variety of factors into consideration when designing the suspension for their vehicles, including ride quality, performance and cost, just to name a few. But since they don’t intend for their vehicles to operate in extreme and harsh conditions, ride quality and cost prevail over performance in the engineering process. So how does it all work?
Most modern vehicles use what’s known as ‘independent suspension’. Simply put, your wheels/tyres are attached to an upright that connects through an array of arms to the vehicle’s chassis. As the upright moves up and down the rad and depending on the points they’re attached at, the wheels will change their angle characteristics. Manufacturers purposely design how these angles change. But when you’re looking to go off the road, the goal of 4WD suspension upgrades is to get the tyres to do what you want them to do, whether it’s gripping in a turn, a straight line or providing control in a drift.
By utilising adjustments in camber, caster and toe, the vehicle reacts in a controlled and predictable way. In order to choose the right adjustments for your vehicle, you need to understand the parts that comprise the suspension system.
- Springs are probably the most basic level of suspension tuning and the first thing most enthusiasts upgrade. These parts are the first ones to absorb the impact from the road. Most modern vehicles feature a coil spring design that’s made of steel alloy wound in a helix-like shape. The springs are measured in length, spring rate and inner diameter.
- Dampers (also known as shocks or struts) smooth out the movement of the springs by absorbing the energy they release. Without them, the vehicle would bounce all around. There are single-way adjustable dumpers that adjust compression; two-way adjustable dampers that adjust compression and rebound, and four-way dampers that add high-speed and low-speed setting for compression and high-speed and low-speed setting for a rebound.
- Coilovers are pre-assembled sets of matched dampers and springs that have a threaded shock body for height adjustment. Coilovers come suited for a wide range of applications, from luxury spec riding to off-roading and hardcore racing. The height can be adjusted through damper or spring length, whereas preload can be adjusted through the spring perch, and rebound and compression characteristic can be adjusted through the damper itself.
- Sway bars, as their name implies, allow each of the 4 corners in independent suspension to act on their own. When you turn in, one corner will experience more load than the other corners, resulting in a body roll. Sway bars connect two opposite corners of the suspension and act like torsion springs. As a result, the action one action sees in relation to the other is limited, leading to reduced body roll and controlled weight transfer.
- Rods and arms connect the upright to the body of the vehicle. Each arm has a function that’s directly correlated to the camber, caster or toe. Since the OEM makes these parts for mass production vehicles, the amount of strength and adjustability is limited.
So the first thing you need to determine before investing in upgrade suspension parts is the main purpose of the build, whether that’s off-roading, drag racing, street driving, drifting or rally racing. Each of these disciplines puts a different kind of strain on the vehicle’s dynamics and requires different settings. There’s no one set up to rule them all, simply because the alignment settings directly impact how the vehicle will react.
Next, you have to consider the type of tyres you’re going to run. While unrelated to the suspension system itself, how the tyres perform is directly related to how the suspension is set up. That being said, upgrading your suspension system can go a long way in helping your 4WD perform on and off the road. However, it’s important that you pick the right setup and have it properly installed and adjusted by an experienced professional who knows what they’re doing. Improperly installed suspensions can put you at risk, especially if you intend on driving on rough and uneven terrain.