Want to know what are 4x4 Shock absorbers ?

A Hawas
Mar 7, 2020
5 min read

Updated: May 20, 2020

The clue is in the name. A shock absorber ‘absorbs’ the shock transferred from bumps and dampens the forces a vehicle is subjected to, by controlling the dissipation of energy within a vehicle’s suspension – regulating the springs’ energy using friction and resistance. Put simply, this is achieved by converting kinetic energy caused by the shock into another form of energy – heat – which is then dissipated. Whilst it is the job of the spring to support the weight of the vehicle, it is up to the shock absorber to control the stored energy of the spring, the vehicle body motions and the sprung and unsprung weight of the vehicle.

An off-road shock needs to be more robust to handle the challenging conditions of both arduous tracks and long outback roads, and therefore capable of withstanding the incredible amount of heat that’s generated.

A shock absorber is a critical part of your vehicle’s control components and its effective operation is integral to the safe operation of your vehicle. Types of 4x4 shock absorbers Generally there are two types of conventional shock absorbers: twin-tube and monotube. Monotube shocks have one tube (obviously) and the piston runs up and down through the oil; with a twin-tube shock, one tube is positioned within the second tube.

“As the shock moves up and down, the oil inside flows through the piston and the foot valve, which transfers oil from the inner tube (or working tube) and the outer tube. This kind of acts like an oil reservoir, and also as an oil jacket, around the shock.

You’ll find twin-tube designs in most road-going passenger cars, SUVs due to their comfortable on-road characteristics. Monotube shocks are typically used on performance-oriented vehicles, and are becoming more popular for 4x4 vehicles – particularly for on-road use.

There are then variants within twin-tube and monotube designs such as nitro-gas charged, twin tubes, single body internal floating piston monotubes, and remote reservoir shocks which move the additional oil capacity out to a separate canister mounted near the shock and connected by an oil line.

There are then additional features such as adjustable damping and position-sensitive damping that can also be built into shock absorbers. Monotube shocks do have a number of drawbacks for off-road environments, (They are) vulnerable to impact damage, and high gas pressurisation can lead to a higher risk of leaking and lower oil volume which can cause overheating.

Twin-tube shocks, on the other hand, are more protected from the elements. Twin-tube shocks are naturally resistant to damage from rocks and debris due to a second layer of ‘armour’ which protects the piston tube, “Lower gas pressurisation also means they are less prone to leaking and can have a longer service life.

Twin tube shocks in general are a more reliable and trouble-free concept for off-roading due to their strong style of construction. Monotube shocks are well-suited to on-road environments where high precision or tuning is required. In some cases they can also be more vulnerable to damage or leaking in an off-road environment.

When it comes to finding a shock absorber more suited to the bumps and grinds of serious four-wheel driving, though Why go to the aftermarket? OEM units are built to a cost – and within bureaucratic parameters – and will be capable enough for most people who don’t depart the grid in search of the old black stump. Manufacturers typically cater for the broader population – which makes sense – but that means the equipment will often be lacking for specific requirements.

For the 4x4 cars the aftermarket is where to turn to ensure you are set up properly for remote travel, hardcore off-roading, or whatever floats your boat, as the industry has a lot more freedom to target specific uses – towing heavy loads, for example.

“The aftermarket generally does away with all the bureaucracy and focuses attention to providing targeted solutions aimed at real-world customer use.

Upgrading your 4x4 with aftermarket gear often leads to a domino effect, and it’s no different for shock absorbers. Installing a lift kit? You’ll need shocks to suit.

As soon as you are looking to raise the vehicle, carry constant loads or look to spend a little more time off the bitumen then the OEM shock absorbers are too short, do not have sufficient damping and are simply just too small to do the job. All of the experts agreed that if you make smart decisions at installation, it’ll save you from a world of hurt down the track… literally. Buy a quality product from a reputable brand, and a shock absorber that suits the kind of driving you have planned, and you’ll be laughing on your camp chair in the middle of nowhere.

“There is no point buying the most expensive, flashy racing shock for a vehicle that is going to circumnavigate the continent, “They are designed for high performance but not necessarily stamina.”

It’s also important to ensure the vehicle is set up correctly: “Ensuring the vehicle is set up correctly and the shock absorbers are not being bottomed out or damaged is the most important factor,”

“Any quality suspension installer should always only tighten shock absorber bushes at ride height, especially lower strut bushes. This is referred to as ‘neutralising the bushes’ and it ensures the bush remains relaxed at ride height to maximise bush life. If the bush is tightened with the wheels hanging, the bush is twisted and is subjected to more torsional stress resulting in shortened life.”

Type of 4x4 shock absorbers

Coilover With a coilover shock absorber, the coil spring is integrated into the design of the shock absorber. “Coilovers are for customers who want the ultimate in performance and tuning ability, with compression and rebound damping, as well as ride height being adjustable,”

Gas-charged shocks Instead of using a foam sleeve like a foam cell shock absorber, a gas-charged shock uses a low-pressure charge of nitrogen gas. Gas-charged shocks are hugely popular in modern vehicles. “Small-bodied, twin-tube, gas-charged shocks are great value for everyday use. Hence why they are popular from the original vehicle manufacturer,”

Remote reservoir Remote reservoir shocks can offer similar benefits than a large-bodied foam cell shock, since the intention is to increase oil volume; but this only works in long travel applications which cycle the fluid in and out of the reservoir, such as dedicated race vehicles, “Modern vehicles with little wheel travel rarely benefit from a remote reservoir shock, as there is simply not enough fluid displacement to transfer the heat into the canister.”