When it comes to upgrading the suspension or GVM of a 4WD, choosing the right components is about much more than selecting a lift height or copying a suspension package that worked well in someone else’s vehicle.
Every 4WD is set up differently.
Bull bars, winches, dual batteries, canopies, drawers, fridges, long-range fuel tanks, roof racks, recovery equipment, tools, towing equipment and touring gear all add weight to different areas of the vehicle. Even two identical Toyota Hilux models can require very different suspension setups depending on what has been fitted and how the vehicles are actually used.
This is why, at Power Curve Automotive, we recommend completing a pre-GVM or suspension inspection before deciding what suspension components should be fitted.
The purpose of the inspection is simple: gather the right information first, then build the suspension package around the vehicle and its intended use.
Set up for you, not your mate.
Suspension Isn't One Size Fits All
One of the most important things to understand when choosing suspension is spring rate.
Suspension springs are available in different load ratings. Depending on the application, you may see specifications such as 0–250 kg, 250–350 kg or other load ranges. These ratings are important because the spring needs to suit the amount of additional load the vehicle is expected to carry.
That doesn’t simply mean how much weight you occasionally put into the vehicle. We are particularly interested in the constant or regularly carried weight that forms part of the vehicle’s normal setup.
For example, a Hilux with an empty tub for most of the week has very different requirements from a Hilux permanently fitted with a canopy, drawers, fridge, tools and touring equipment. Likewise, a vehicle with a steel bull bar and winch has more permanent weight over the front axle than an otherwise standard vehicle.
Installing a heavier rated spring isn’t automatically better.
A spring that is too light for the application may not adequately support the load, while selecting a significantly heavier spring simply because another vehicle uses it can result in a setup that doesn’t suit your vehicle or how you use it.
This is exactly why we don’t recommend building your suspension around your mate’s 4WD.
Their vehicle may look similar, but the actual weight distribution and intended use can be completely different.
We Start by Looking at the Vehicle as It Is
Before recommending suspension, we inspect the vehicle in its current configuration.
At the front, we look at accessories such as the bull bar, winch, additional batteries and other permanently fitted equipment. We also inspect the condition of the existing suspension and associated components.
The rear of the vehicle is equally important. A canopy, drawers, fridge, tools, recovery equipment, tow bar and other accessories can contribute a considerable amount of permanent weight before passengers, luggage or a caravan are even considered.
We also look inside the vehicle and canopy.
This can sometimes be overlooked when discussing suspension because individually the accessories may not seem particularly heavy. However, once drawers, fridge slides, fridges, electrical systems, inverters, tools, water, recovery equipment and other touring accessories are combined, their contribution to the vehicle’s overall weight can become significant.
Rather than estimating based solely on what we can see from outside, we want to understand the complete vehicle setup.
We Put the Vehicle on Our Scales
Power Curve Automotive’s ability to carry out GVM and GCM upgrades means we have access to calibrated vehicle scales in our workshop.
This gives us information that can’t be obtained simply by looking at the vehicle.
We can determine the vehicle’s current weight and, importantly, assess how that weight is distributed between the front and rear.
This becomes particularly valuable when determining appropriate suspension requirements and considering axle loads.
A vehicle can have substantial weight concentrated at one end. A heavy steel bull bar and winch influence the front, while a canopy, drawers and touring equipment can substantially increase the rear load.
Knowing the current weights gives us a much stronger starting point when selecting suspension than simply saying, “It’s a Hilux, so this is the kit it needs.”
GVM Upgrades Require More Than New Suspension
When we’re assessing a vehicle for a GVM upgrade, there are additional requirements that need to be considered.
A GVM upgrade isn’t simply a matter of fitting heavier springs.
We need to establish whether the vehicle and its existing setup are suitable for the relevant upgrade and identify anything that needs attention before proceeding.
As part of our pre-check, we may record and confirm information including the vehicle identification details, engine number where required, tyre placard information, tyre and rim specifications and the vehicle’s existing weights.
Tyres and wheels are particularly important.
We check the tyre size, rim size and applicable load ratings against the requirements of the proposed GVM application. Changing the vehicle’s suspension does not make unsuitable tyres or wheels compliant, so these items need to form part of the overall assessment.
Doing this before the upgrade allows potential issues to be identified before parts are ordered or work begins.
The Vehicle Also Needs to Be Roadworthy
A vehicle being presented for a GVM upgrade must be in an appropriate roadworthy condition.
For that reason, our pre-check also includes a visual inspection for mechanical concerns or damage that could affect the upgrade process.
We inspect suspension mounting points and components including areas such as the upper and lower control arms, bushes and related hardware, depending on the vehicle and application.
If a bush is badly deteriorated, a component is damaged or another roadworthiness issue is present, fitting new suspension over the top of the problem isn’t the correct solution.
It is much better to identify these concerns before the upgrade.
That gives the owner an opportunity to understand what is required and allows the work to be planned properly instead of discovering additional repairs halfway through the installation.
Then We Need to Understand What You Actually Do With the Vehicle
The physical inspection and weight measurements only tell us part of the story.
The next part comes from talking to the owner.
We want to know what you’re trying to achieve.
Do you tow?
If so, what are you towing? A box trailer occasionally places very different demands on a vehicle compared with regularly towing a caravan.
Do you tour?
A vehicle travelling long distances on the highway with a caravan and a full touring setup has different priorities from a lightly loaded vehicle predominantly used around town.
Do you travel off-road?
Off-road use may be less relevant for some owners, but for others it is an important part of determining the most appropriate suspension application.
We also want to know what accessories you intend to add in the future.
If you’re about to install a canopy, drawers, fridge and additional touring equipment, setting the suspension up around the vehicle’s current empty configuration may not produce the result you want once everything is fitted.
The more accurate information we have, the better we can plan the finished vehicle.
GVM and GCM Need to Be Considered as Part of the Whole Vehicle
For owners who tow, vehicle weight can become even more important.
It is easy to focus entirely on the caravan’s weight while overlooking what is happening to the tow vehicle itself.
Passengers, fuel, accessories, luggage, recovery equipment, canopy setups and tow-ball load can all contribute to the vehicle’s operating weight.
Where a GVM or GCM upgrade is being considered, we need to look at the applicable limits and the vehicle’s actual configuration rather than treating suspension as an isolated component.
Our calibrated scales assist us in establishing where the vehicle currently sits and give us useful information when discussing what the owner is trying to achieve.
Sometimes the numbers confirm that the planned setup is straightforward.
Other times they highlight something that needs to be reconsidered before additional equipment is fitted.
Finding that out beforehand is much easier than finding it out after the vehicle has been fully built.
Why We Recommend Doing the Pre Check Before Ordering Suspension
We regularly see the difference between vehicles that have been planned from the beginning and vehicles where suspension has been selected first and questions have been asked later.
When the process is followed properly, we can take into account the vehicle’s existing weight, front and rear load, accessories, tyre and wheel specifications, mechanical condition and intended use before recommending an application. That significantly reduces the chance of surprises.
When important information is missed, the vehicle may need additional components afterwards. In some cases, parts need to be changed again because the original setup wasn’t suited to the finished vehicle. That can mean additional labour, additional parts and additional expense.
More importantly, it can leave the owner disappointed because they have invested in a suspension upgrade without achieving the result they expected.
Doing the homework first gives us a much better opportunity to get the vehicle right the first time.
Plan the Vehicle as a Complete Package
A good suspension setup isn’t determined by what looks good in a catalogue or what another owner recommends online. It comes from understanding the complete vehicle.
What does it weigh now?
Where is that weight located?
What accessories are permanently fitted?
What still needs to be fitted?
What tyres and rims are being used?
What condition is the existing suspension in?
Are the control arms, bushes and mounting points suitable?
Does the vehicle tow?
Is it primarily a highway tourer?
Does it regularly travel off road?
Is the owner looking for improved load carrying, a GVM upgrade, a GCM solution, suspension improvements or a combination of these?
Once those questions are answered, we can make a much more informed recommendation.
At Power Curve Automotive, that is the reason behind our pre-GVM and suspension checks. We would rather take the time to inspect, measure and understand the vehicle before recommending components than fit a generic package and try to solve the problems afterwards.
Every 4WD is different, and the suspension underneath it should reflect how that particular vehicle has been built and how its owner intends to use it.
Set up for you, not your mate.
