Essential questions for your four-wheel drive suspension upgrades

Navigating the many choices and considerations for a four-wheel drive suspension upgrade can be daunting. But don’t worry, we are here to help.

Let’s face it: standard four-wheel drive suspension has its limitations. It’s often built to a price, and not designed to handle the long-term rigours of off-road usage. Springs start to sag, shock absorbers wear out, and performance disappears. And of course, sometimes we want to improve the performance and capability of our four- wheel drives.

We do this with upgrades, to the vehicle and to the suspension. Extra protection and things like bullbars are great, but can also weigh your car (and it’s suspension) down. Off-road ground clearance can be improved with a lift, and those weights can be better catered for with a quality aftermarket suspension setup. So instead of replacing your standard with the same old stuff, you’re much better off going for an upgrade.

But what should you go for, and how much should you spend on a suspension kit for your four-wheel drive? Getting your head around all of the considerations can be daunting, but you also want to know that you are choosing the best setup for your own circumstances. To help you on your own journey, here is a list of important considerations you should make when you are looking for your next suspension upgrade.

What kind of driving are you planning on doing?

If the suspension upgrade is for the family four-wheel drive that heads out on the school run most days – with the occasional beach run or weekend of camping thrown into the mix – chances are you don’t need to go all-out on your suspension.

Things like upgraded control arms, remote- reservoir shock absorbers and a GVM upgrade might be overkill, in this case. But, if you’ve got that Simpson Desert pilgrimage planned next winter, or there’s a 20-foot caravan in your future, then you should consider this when choosing your own new suspension setup.

Long-distance four-wheel drive touring and remote-area travel demands a higher level of quality, because it’s your suspension in the firing line against the endless challenges of corrugations. Reliability is of the utmost importance, to ensure critical components – especially shock absorbers – don’t fail against the rigours against off-road driving.

You want larger shock absorbers in this instance, with more oil capacity, a quality construction and nitrogen gas (to improve resistance to fading and cavitation) to be able to handle the conditions.

If you’re planning on towing heavy loads, then your suspension system will be under similar strain. Heavy loads – especially over the rear axle – can overwhelm standard springs and shock absorbers, especially over long distances.

Heavy-duty suspension, something that is capable of handling increased loads for sustained periods of time, is what you need here. And this is especially the case if you’re towing something that’s right at the braked towing capacity, with a commensurably high load being transmitted through the towball. We’ve all seen that tow vehicle, rear hunched down and nose pointed up to the sky, suspension overloaded and not fit for purpose.

Don’t be that guy. Ensure your trailer is correctly loaded, and have the right kind of suspension fitted to your tow vehicle to keep things stable, safe and enjoyable to drive.

What kind of weights are you generally carrying?

This is an important factor, and one that could make all of the difference in the world in terms of ride quality. Suspension should be tuned according to the kind of load that you have on-board most of the time, or when suspension performance is most important to you.

For example, driving solo with only a little bit of gear means your vehicle is in an unladen state, and you’ll get a harsh ride if your suspension is tuned for heavier loads. And conversely, suspension tuned for unladen vehicles and light loads will sag and feel uncontrolled when working against heavy loads.

A suspension kit that is tailored to your vehicle, and the weight that it will be carrying, will offer the best performance, comfort, durability and value for money in this regard.

Suspension kits that include progressive- rate coil springs can allow for a broader range of capability in this regard, giving a supple ride quality but giving good load- carrying capabilities at the same time.

Good quality dampers have multi-staged valving systems, which gives the ability to respond to big suspension inputs more firmly, offering increased levels of control in different scenarios also also giving a quality ride comfort.

Are you planning any modifications?

Firstly, modifications often include additional weight that the vehicle (and it’s suspension system) needs to contend with. Bullbars, winches, underbody protection and the like all add to the effective kerb weight of the car. It’s reducing your payload, but also increasing the base load of weight that your suspension needs to handle.

Springs will sag against the heavy load, which one can often witness in a standard four-wheel drive having a lowered static ride height at the front after the owner has fitted a heavy steel bullbar. Drawers, spare wheel carriers, roof racks and long-range fuel tanks can sag rear suspension as well, pushing you closer to the bump stops and limiting the amount of available wheel travel.

The solution here is a new set of springs, which is tuned correctly to handle the amount of weight and dynamic force your fourby is going to dish up. You can restore (or increase) that factory ride height, and get a much-improved ride quality to boot.

Progressive-rate coil springs can be really advantageous in this case, especially if you’ve got a vehicle that has varying levels of load on-board. A Coil spring that has a varying stiffness level at different sections can give the ability to handle the heavy loads, but also maintain a nice unladen ride quality at the same time.

We can’t forget dampers here, either. When you change the spring rate and ride height of your four- wheel drive, it would be remiss not to update (and upgrade) your dampers to match. Look for something that is expertly tuned to suit the vehicle and suspension setup, with the correct levels of bump and rebound damping to maintain good levels of control and comfort.

Good quality aftermarket dampers will offer extra benefits as well, through their heavy-duty nature. These will often be more durable in their construction, and offer better resistance to fade after long stretches of corrugations and sustained impacts.

And while you might be looking at a suspension lift to accommodate larger tyre diameters, don’t forget also that bigger rubber (and bigger aftermarket wheels) weight more than the factory setup, which needs to be taken into consideration.

Wheels and tyres form part of your ‘unsprung mass’ along with suspension control arms and some driveline components. An increase in unsprung mass can be detrimental to ride quality and control over rough surfaces, and will be more demanding of the the suspension system to handle the weight.

Will you be overweight? You might need a GVM upgrade

No, I’m not talking about how many notches you have left on your belt. Instead, I’m talking about the weight of your four- wheel drive vehicle. Once you consider all of the above points, and weigh them in against your allowable payload, you need to be sure that you are not illegally overloaded.

If you’ve exceeded your allowable Gross Vehicle Mass (GVM), there can be serious ramifications for yourself, other road users and your insurance circumstances.

And considering the relatively meagre payload available on some of Australia’s most popular four- wheel drives, it comes as no surprise that a GVM upgrade is the solution many need.

GVM upgrades have two important factors. On one side, the upgrade includes replacement suspension components that are engineered and approved to carry the weight beyond the scope of the standard vehicle’s GVM. In other words, it’s all purpose-built, heavy duty gear. The other factor is compliance with national and state government road regulations. With a proper certified GVM upgrade installed on your vehicle, you now have a fully legal increased GVM and improved payload, and all of the required paperwork to back it up.

Can you trust what you are installing?

While it might be tempting to shop around on price for your suspension, the old adage of ‘you get what you pay for’ rings true in this regard.

Suspension is one of those things that you will experience and interact with every time you drive your car, so it pays not to skimp out on something cheap and unsatisfactory. Go for quality, through a reputable brand that has proven runs on the board. We say this, for a couple of reasons.

Firstly, good quality suspension equipment will go the distance, and will likely prove to be a more cost- effective solution over the long term (especially when you consider the hassle and costs of installation). Do it once, do it right.

Furthermore, a suspension system that has been expertly developed, engineered and manufactured will give superior performance over something more generic. You’ll get something with dampers that match the springs, and can provide the optimum levels of capability, comfort and durability.

It’s difficult to look at a suspension system and see where the value for money is, because the difference in quality is hidden on the inside, and will only become apparent after you sample the driving experience and see how long it lasts for.

Consider supporting an Australian-made and Australian-owned business, as well. You’ll be much better placed for support further down the track, and you’ll have the comfort of knowing your not just supporting Aussie jobs, but you’re tapping into the huge wealth of expertise that comes from the Australian aftermarket four-wheel drive industry.

If it’s a live-axle four- wheel drive, your suspension upgrades might be making adjustments to the castor angle of your vehicle, which will affect driving dynamics. Big suspension lifts can run into problems like this, which can often only be solved through expensive aftermarket control arms or compromised castor- correcting bushings.

A 2-inch lift, which offers a good improvement without going overboard, avoids problems like this and allows the driver to have a more cost-effective solution.

Four-wheel drives with independent front suspension, which is the most common setup these days, have problems surrounding wheel alignment and camber angle, when including a suspension lift into the list of modifications. This doesn’t just change the way that your vehicle steers and self-centres, but can also be detrimental to tyre wear and grip.

Every vehicle is different in this regard, so consult an expert on what you might need for your circumstances. But, some vehicles will really benefit from an updated upper control arm, which has more scope of movement to put suspension geometry back within the scope of factory settings.

Conclusion

It’s no surprise that so many Australian four- wheel drive owners opt for a suspension upgrade on their vehicles, either brand- new off the showroom floor or when their standard stuff starts wearing out.

Whether it’s chasing improved performance, wanting better durability and reliability, or even just making sure you are on the right side of the law, there is a solution out there for your own needs and at your budget, that will give you quality and confidence whenever you next get behind the wheel.