A GVM Upgrade and Why You Need It

If you plan to upgrade your ute in any way, your Gross Vehicle Mass (GVM) will be affected, and we’ll explain how.

Why do I need a GVM upgrade?

Most people have seen the acronym GVM (Gross Vehicle Mass) somewhere in their owner’s manual before, few understand what exactly it is and how it’s affected, and even experienced off-roaders can easily misunderstand and overload their vehicles.

At Trayon Campers; we get asked this alot. The fact that our campers are so light-weight makes customers think they need not concern themselves with a GVM upgrade and yet when they talk to us or read our massive library of blogs – We are the biggest ambassadors for GVM upgrades in our industry. Not because of our campers weight (being the lightests in its class – spec for spec) but because of the other accessories and upgrades customers add to their touring rigs.

We’re here to help you get a handle on how important it is to be aware of your ute’s actual numbers and how to stay safe.

In this article, we share what we have learnt over the last 20+ years of experience fitting out 4×4 Utes for expeditions in some of the toughest and remote terrains Australia has to offer.

Many of our customers do some of the most punishing tracks like the Canning Stock Route, Old Telegraph Track and the Gibb River Road.

We’ll walk you through some of the common hiccups while modifying your ute and how to keep your vehicle safe in the middle of nowhere and road legal.

If you plan to load your ute with gear for the adventure ahead or plan on getting a trailer and are concerned with your rated towing capacity, then this article is for you.

Payload and Towing limits in Australia – A Little Complex to Understand

The vehicle manufacturer’s specifications outline the Gross Vehicle Mass (GVM), Gross Combined Mass (GCM) and Kerb / Tare Weight. The towing capacity is often quoted. However, sometimes it’s a bit harder to find the payload. Nowadays, the payload is usually listed in the owner’s manual, but you can also calculate it by subtracting the Kerb Weight from the GVM.

In addition to these manufacturers’ specifications, the manufacturers have to comply with the governing vehicle legislation in Australia, which is vastly different to other countries.

The Australian Design Rules (ADRs) are a good place to start to understand the who, what, where, and when revolving around why your ute has the GVM weight limit that it does. The Department of Infrastructure has a lot of useful information that you should be aware of before you install the kitchen sink. However, many of us don’t have the time nor the energy to go through the mountains of documents.

The maximum GVM that you can drive on a car license is 4,490 kg; that’s the ceiling, the upper limit – most utes are designed to be under this with the exception of the American pickup trucks like the Ford F250 which actually need a GVM downgrade to drive on a car license.

Similarly, as a side note the maximum GCM (Gross Combined Mass) you can drive with a car license is 9,000 kg. Again, most manufacturers are well under this.

The number of government entities involved with this determination can leave your head spinning but it all boils down to safety standards and federal department guidelines.

It’s a good idea to pay attention when safety is involved for a few reasons:

1. In the end, it’s the owner’s responsibility to understand and follow all applicable guidelines because if something were to happen, it would not fall on the installer/modifier for legality purposes.
2. If there’s a 1% decrease in accidents or incidents nationwide, the government is fully justified in its mitigation. You will not persuade any authority otherwise regarding safety.

So let’s get into how to keep within the confines of your GVM specifications and what options are available to increase your GVM and remain legal & safe.

Payload Capacity is Smaller Than it Seems

• Water
• Oil
• Radiator Fluid
• Diff Fluid
• Transmission fluid
• Luggage
• Dog
• Food
• Camping Equipment
• Tools
• Fridges
• Other beverage
• Cooking equipment, cutlery & crockery

And most importantly, it ALSO includes your 4×4 accessories:

• Front Bar
• Side steps
• Winch
• Underbody bash plate
• UHF
• Roof racks
• Snorkel
• And anything else you want.

All these little things add up and eat away your payload very quickly. If you haven’t done your numbers you can easily overload the average 1-tonne ute in Australia. Below we will run through the exact weight figures of a recent build so you can see just how quickly the payload reduces.

For New Vehicles: Do This Before First Registration

If you are buying a new vehicle, ensure you plan ahead and anticipate the weight of your modifications or upgrades if you can, speak with your insurance company and your local upgrade professionals to get exact weights & quotes.

You might find that having that amazing, yet heavy aftermarket accessory might mean you can’t take passengers legally.

Why do it before the first registration? Because when you register your vehicle, it becomes significantly more complicated to upgrade your GVM. You have to pay for the upgrade, get the engineering inspected then convince the state transportation authority that it was done legitimately.

Second Stage Manufacturing GVM Upgrade

If the numbers exceed the payload prior to registration you can explore what’s called a second stage manufacturing GVM upgrade. These are Federal Government approved suspension upgrades to your new vehicle before it is registered, giving you more payload to play with. After the GVM upgrade has been made to a new vehicle and a compliance plate issued, it is only then that the vehicle can be registered with the updated GVM and driven in Australia.

For Registered Vehicles: How To Get a GVM Upgrade

If the ute has already been registered the situation becomes a bit complicated. In Queensland as an example, you can’t get a GVM upgrade after registration of more than 10% of the original GVM. In other states, you may be able to get a bigger GVM upgrade and also pay for an authorised engineer to inspect the vehicle in order to provide a compliance certificate. However, this is oftentimes subjective to the engineer and not guaranteed and the rules vary from state to state. So please check with your regulatory authority.

Payload Fitout Example of a 2021 Toyota Hilux SR Extra Cab 4×4

As a slide on camper manufacturer, we realised early on that sometimes all these numbers get confusing for our customers, so we created what we call the “Turnkey” service for our Trayon Customers.

This is where our customers have an idea of what they want on their new rig but may not know how to get from point A to point B and in what order to do things with the right equipment.

So we source the vehicle using our fleet buying power, accessories and camper, while also facilitating the installation to ensure the entire build gets done properly. It’s an end-to-end process making it easier for our customers to get a rig together for their touring purposes.

Just keep in mind that, although we help build the vehicle for you and do our best to ensure you’ll be road legal and safe. It is still a choice-driven process by the customer and Trayon isn’t legally responsible for the outcome of these choices.

GVM upgrades and putting together the figures can be a daunting task that often involves many people and a project manager, just like renovating or building a house.

However, through many years of research and development, we have developed a streamlined process to pull the team together and facilitate the build.

Below is a full example of a build for a customer’s 2021 Toyota Hilux SR extra cab Automatic 4×4, 2.8 Turbo Diesel – a cab chassis – vehicle manufacturer listing the GVM at 3,100 kg.

Item	Weight (KG)
Toyota Hilux SR Extra-cab Auto 4×4 – 2.8L Diesel – CAB/CHASSIS GVM = 3100kg
VEHICLE	1905
2100mm long HD alloy tray with removable sides and tubular headboard	137
1800mm long under tray drawer	103
TRAY	237
APPROX. TOTAL VEHICLE KERB WEIGHT	2145
GVM (3100KG) MINUS NEW KERB WEIGHT – IE: PAYLOAD RATING	955

Using our Turnkey service and a brand new vehicle that we sourced at fleet prices.

Cab-Chassis Payload Numbers – A Bit Confusing

Toyota states at this current configuration of this model ute itself is 1,905 kg. This charted weight is what Toyota has listed for the ute minus the tray for the cab chassis.

Confusion might creep in at this point because from the consumer point of view, the ute is sold to them thinking that this figure is the Kerb Weight. So the payload would be 1,905 Kg subtracted from the total 3,100 GVM which would leave 1,195 Kg remaining as the payload.

Unfortunately, using this math will set you up for failure because what they don’t make glaringly obvious is that the Kerb Weight DOES NOT include the tray when you buy a cab/chassis. So the example above shows what the Kerb Weight becomes after you add an aluminium tray. Leaving 955 kg as your payload and if you’re planning on adding anything extra beyond this point, your options become very limited.

What was once a one-tonne ute is no longer a reality simply due to adding the necessary tray to make the vehicle usable.

This is where a GVM upgrade comes into play, it can give you back a few hundred kg which can make all the difference and give you a safety margin.

Steel Tray vs Aluminum Tray

The aluminium tray fitted in this example is very strong, however, some people have it in their head that a steel tray is even better. The truth is, a steel tray pushes the weight further and this is before we even start talking about 4WD accessories, campers, luggage & people.

Some steel trays are roughly another 200-400kg heavier than their alloy counterparts. So you would be taking another couple of hundred kg off the payload.

Gone are the days where aluminium trays are flimsy and weak. So our recommendation is to get a heavy-duty aluminium tray from a reputable manufacturer. If you do go steel, it’s definitely a no brainer that you get a GVM upgrade.

After Market Accessories & Second Stage GVM Upgrade

Per the customer’s request, we continued after the tray install to include all the supporting equipment they asked for.

Remember that we are here to support the customer’s requests but in no way are responsible for GVM issues down the road. The preparation after install/modification is entirely up to the customer. We will assist and advise but accountability rests on the vehicle owners shoulders alone.

Once we added all the accessories that the owner wanted on paper, it was obvious that a GVM upgrade was necessary for this build. We were able to secure a second stage manufacturing GVM upgrade from 3100 kg to 3620 kg through Pedders suspension which adds another 520kg to this vehicle’s payload capabilities.

In this upgrade they replace the factory springs, shock absorbers and upgrade the brake pads so you can easily pull up with a higher constant load.

After the vehicle is registered with this new upgraded GVM, the next stage is what we call “Third Stage Fitments”, that’s adding the 4×4 accessories and installation sourced from several aftermarket companies as to what the customer wants.

The third stage fitments for this example included the following 4×4 accessories (total weight listed toward the bottom)

STEEL WINCH READY BULLBAR

SIDE RAILS

SIDE STEPS

UNDER VEHICLE PROTECTION PLATES

FRONT RATED RECOVERY POINTS

10,000LB SYNTHETIC ROPE WINCH WITH WIRELESS REMOTE

SNORKEL

ALLOY ROOF RACKS

MAXTRAX

SHOVEL

COMPRESSOR

UHF RADIO AND 6.6BD AERIAL

LED DRIVING LIGHTS

FRONT AND REAR DIFF BREATHERS

RECOVERY KIT

TIRE SEAL KIT

LITHIUM ENGINE JUMP STARTER PACK

CANVAS FRONT AND REAR SEAT COVERS

2.0M SAND FLAG

SECONDARY FUEL FILTER

ENGINE CATCH CAN

UNDERTRAY TOOL BOXES TAPERED AT REAR

CAMPER CHARGE CONNECTION (12V)

PORTABLE COMPACT FIRE EXTINGUISHER

RUBBER UTE TRAY MATT

TOW BAR

THE FOLLOWING ITEMS REPLACES ORIGINAL OEM PARTS (IE: SOME WEIGHT OUT AND NEW WEIGHT IN):

ALLOY WHEELS x 6 + ALL-TERRAIN TIRES WITH HIGHER LOAD RATING x 6 (replacing original 5 plus adding secondary spare wheel)

140L LONG RANGE FUEL TANK

TOWING MIRRORS BLACK

3RD STAGE FITMENTS	438
APPROX. TOTAL VEHICLE KERB WEIGHT	2580
UPGRADED GVM (3620KG) MINUS NEW KERB WEIGHT – IE: PAYLOAD RATING	1040

So, we added:

The winch, the snorkel, the roof rack, the max tracks, the shovel, the compressor, the UHF radio, the led driving lights, the front rear diff breathers, the recovery kit, Lithium jump start kit, canvas seat covers, two-meter sand flag, secondary fuel filter, engine catch can, storage boxes at the rear behind the wheels, the camper charge connection point, compact fire extinguisher, Ute mat and a tow bar, large fuel tank as well extended mirrors.

We also added a 6th spare tire and upgraded to lighter weight alloy wheels. All this comes to around 438 kg, which took the vehicle weight up to 2,580 kg. So if we consider that to be our new Kerb Weight, let’s calculate the remaining payload.

3620 kg – 2,580 kg = 1,040kg.

If you added these accessories without the GVM upgrade, your remaining payload would only be 955 kg – 438 kg = 517 kg which still doesn’t account for a slide on camper, luggage, additional water, food or drinks etc! Which could easily be over 517 kg.

So why get a GVM upgrade? So you have room in your payload for the important things. Without a GVM upgrade, your 4WD accessories could easily take up close to half of your 1-tonne payload depending on what choices you make in relation to fitments from the original manufacturer stated cab/chassis kerb weight.

Weight Distribution Between Front & Rear Axles

When you are calculating your weights, you also need to consider your weight distribution on the front and rear axles. It is possible to be under your overall payload, but exceed your payload on one of the axles – most of the time, the front axle gets overloaded.

When you do get a GVM upgrade, it’s not an even upgrade of front and rear axle load capacity. There is an emphasis on the rear axle. With the GVM upgrade done on this vehicle in the example – there was a 160kg payload increase on the front axles as part of the increase which was needed to allow for the extra weight added to the front:

		Front axle (original 1450)	Rear axle (original 1700)
Vehicle tested tare weights:	2580	1460	1240
Upgraded GVM figures:	3620	1620	2000
Payload remaining:	1040	160	760

Notice that the load on the front axle was 1460 kg after we added the front end accessories like a winch, bullbar, side steps, spotlights, UHF etc, it would have been over by 10kg from the original 1450kg manufacturer limit if we hadn’t upgraded the GVM with this particular package from Pedders.

Longevity of your Vehicle

When doing your numbers, try to avoid being so close to your legal payload limits, whether before or after the GVM upgrade. This helps ensure the longevity of your vehicle and helps protect the vehicle components, as it gives you tolerance for when you are going up and down harsh undulating terrain where there are multiplicative forces pushing down on the components.

Is a GVM upgrade worth it?

The folks over at Pedders think so and have spent years proving it. For over 70 years they have been improving and testing all sorts of vehicles from the early days of improving lever-type shock absorbers to the GVM upgrades of today.

The technicians at Pedders understand that a lift doesn’t always mean a “GVM Upgrade” was accomplished. The purpose of adding a GVM upgrade is to remain safe while adding the fun bits to your ute i.e. weight.

What’s interesting about the Pedders GVM upgrade is that it doesn’t provide the full 48 mm lift that is common among the competitors.

Instead, they opted for a more moderate lift of around 36mm – 38mm (our measurements), allowing for both upstroke and downstroke of the shocks while also increasing capabilities and keeping the ride quite pleasant both laden and unladen.

So as you’re driving around without a load on the tray and you go over a speed bump – the suspension compresses and then it kicks back. Well, there’s still some upstroke left in the shock absorber. So the shock absorber has a chance to do its job and move upwards to mitigate the jarring effect.

Some of the other GVM upgrade options available often put the shock absorbers at their maximum upstroke to assume a constant load of several hundred kg to permanently compress the shock absorber down, so then you can have room for upstroke and downstroke. When you take the load off and go over the same speed bump – the shock absorber has no upstroke left and that’s where some of the jarring effects come from.

Sadly this configuration makes the unladen ride sometimes uncomfortable. So Pedders have helped mitigate that issue by limiting their height increase to allow upstroke in their shock absorbers.

Why Not Get a 4×4 Truck?

Some might say, if you need a GVM upgrade on your mid-range ute to cart all the stuff you want to take with you then why not get an actual truck that you can drive on a car license? Like a Fuso Canter 4×4 or a Isuzu NPS 4×4?

They are 4×4 trucks made to carry weight in a commercial application so it should be a better choice for your touring vehicle right?

Unfortunately not; other than the obvious shortcomings of the 4×4 truck range:

• Very tall, wide and long vehicles compared to a mid-range ute
• Lacks many creature comforts and safety features compared to a mid-range ute
• Almost twice the price of any mid-range 4×4 ute
• Limited off-road capability due to dual-rear wheels and overall weight compared to a mid-range ute
• More expensive servicing, parts and components compared to a mid-range ute
• A bigger vehicle means a heavier vehicle as well as heavier components/upgrades like bullbars, trays, winches and spare tires compared to a mid-range ute
• More strenuous ergonomics (eg: harder to get in and out of the driver seat or change a flat tire) compared to a mid-range ute
• Harder to park in town or at home compared to a mid-range ute

Everyone keeps forgetting about the GVM ceiling, the upper limit of what you can drive on a normal car license (ie: not a truck license). The 4495kg limit brings the same problems to this 4×4 truck range in their payload capabilities as to a mid-range ute with one massive difference:

• You can upgrade the GVM of a mid-range ute and still drive it with a car license, whereas if you exceed the payload of a 4×4 truck then your only option is to upgrade its GVM beyond the 4495kg and go get your truck license. This brings more responsibility as a truck driver, you will need to have the vehicle inspected periodically (take it over the pits) for registration purposes depending on which state it’s registered.

It also means only people with a truck license can drive it.

A Bigger Vehicle Means a Bigger Kerb Weight

So what about the extra-large 4×4 American Pickup trucks like the Ford F250 super duty. They have all the creature comforts that the mid-range segments have and they have a massive cargo area, so surely you can carry more.

Actually, this is a common misconception in Australia. You’ll find that their payload is actually around the same or less than most of the mid-range utes when driven on a car license.

This is because it is such a large, heavy vehicle, that the Kerb Weight takes up most of the 4495kg GVM available on the car license.

So run into the same issue as you do with a 4×4 truck.

Risks of a GVM Upgrade

In our experience, one of the biggest reasons people get GVM upgrades is of course to stay safe and be within the limits when they are setting up their ultimate tourer.

However, another reason is to avoid the penalty of a fine by the police or traffic authority officer who randomly asks you to drive onto the scales.

You’ll need to show that you have done your due diligence by getting an upgrade and that your current load is within the upgraded GVM limits.

If there were an incident; the insurance company will also want to see that you have done your due diligence to take that into consideration during their investigation.

As long as your load is within the GVM limits of the specified compliance plate of the upgrade you should be safe.

But what about voiding the manufacturer’s warranty?

Well, we can’t speak for the vehicle manufacturers, however, if say your gearbox died and had a second stage manufacturing Gross Vehicle Mass upgrade which is ADR approved, the manufacturer would need to prove that it was caused by overloading the vehicle beyond their stipulated limits, which is not an easy thing to do.

That being said, before you buy the vehicle, always do your research first.

GVM Upgrades In summary

Gone are the days where you could slap a bull bar, winch and roof racks onto your registered ute and go; “she’ll be right mate”. It’s time for people to start becoming more aware of the weight compromise with each accessory you add.

It’s just like before you buy a house, you have to do your due diligence and do the maths. You’re the one who is going to be driving the vehicle. So you’re the one who is going to be responsible for the load you carry.

Remember this, if it did not come from the factory floor, it adds weight and will affect your GVM.

Almost every other day we get customers who build their ideal ute after registration and quickly realise, after adding accessories, there is little to no room left for all the other important things and sadly regret it later.

Something that is meant to be fun, can quickly become a very very late night in the shed pulling expensive accessories off your vehicle, or worse.

So if you are looking at a Trayon Camper, be sure to check out our Turn Key option to ensure your ultimate camping vehicle is set up for success from front to rear.