GVM & Axle Upgrades

Whether you’re carrying tools of the trade or packing up the 4×4 for an extended trip, your vehicle can become dangerous and illegal if it exceeds the allocated gross vehicle mass (GVM).

The GVM is the maximum a vehicle can weigh when fully loaded. Everything you place on or in your vehicle adds to the overall GVM – fuel, accessories, cargo (including passengers), the tray body for cab chassis models, and even the tow ball load applied by a boat or camper trailer.

A legal GVM is set for all vehicles as part of the Australian Design Rules (ADR) approval process. If your vehicle exceeds these limits you could be up for a costly fine, void your insurance and make your vehicle unsafe.

To combat these issues, ARB offers Old Man Emu GVM upgrades in line with ADR requirements for a number of new, unregistered vehicles.

OLD MAN EMU GVM UPGRADES
New vehicle GVM upgrades are only granted by the Federal Department of Infrastructure and Transport after detailed tests have been carried out by Old Man Emu Suspension Engineers. We ensure that the increase in a vehicle’s GVM following the fitment of a complete suspension system meets the minimum ADR safety requirements.

Once the approved suspension system and GVM upgrade compliance plate has been fitted to your vehicle by an authorised Old Man Emu installer, it can be registered according to its new, increased GVM. This process ensures that your vehicle is GVM legal in all states of Australia.

Already registered vehicles fall under the jurisdiction of their state authorities. The need for GVM upgrades post-registration should be discussed with your local ARB State Office, as regulations differ between states and other requirements may be imposed locally.

OLD MAN EMU FRONT AXLE LOAD UPGRADES
The final weight over the front axle of your vehicle is often determined by the weight over the rear axle, as more rear axle weight will reduce the downward pressure over the front axle. Therefore loading and unloading of weight on the rear of a vehicle, such as unhitching a trailer or removing your touring gear, can play havoc with weight distribution across your front axles in accordance with the manufacturer’s front axle load limits.

To assist in providing greater flexibility in managing load variations as you need, ARB offers a range of Old Man Emu front axle capacity upgrades for the most popular 4×4 models when installing an Old Man Emu suspension package. With up to an additional 170kg of verified front axle load, tourers and tradies alike can have peace of mind that dynamic shift in weight distribution is being aptly supported across both axles.

DOES A GVM UPGRADE INCREASE MY GCM?
A Gross Vehicle Mass (GVM) upgrade is an independently engineered and tested suspension solution which allows users to increase the payload of their vehicle from what the manufacturer originally designated.

While this doesn’t alter the towing capacity or Gross Combination Mass (GCM) of the vehicle, it does assist in managing ball weight on the tow vehicle managing your vehicle’s GVM limit.

WHAT'S INVOLVED IN A GVM UPGRADE?
A GVM upgrade is achieved by fitting a purposely packaged solution of shock absorbers, springs and other suspension components which are tested and accredited by an independent engineer. Assessment includes braking and stability control testing to ensure that each vehicle and package combination maintains all of the vehicle’s safety standards while capable of carrying a greater payload.

Upgrading a vehicle’s GVM is finalised by registering the vehicle at the higher capacity, as well as the suspension upgrade documentation to the respective state authority’s database to officially document the approval.

Customers also receive a copy of all the accreditation documentation.

CAN I GET A GVM UPGRADE IF MY VEHICLE IS ALREADY REGISTERED?
Yes.

Upgrading a vehicle’s GVM before first registration is much easier, as the vehicle is in its original manufacturer’s state including tyres with no vehicle alteration. This can be done at any ARB store or stockist.

To upgrade a vehicle which is already registered, you can still order the same package, however you’ll then need to have the vehicle independently engineered. Your ARB store will be able to point you in the right direction as to who can help perform this task, which is generally very simple.

DOES A GVM UPGRADE REDUCE MY TOWING CAPACITY?
No.

A GVM upgrade does not change how much weight your vehicle is legally allowed to tow, as it does not increase the Gross Combined Mass (GCM). However, owners do need to understand that any weight added to your vehicle, whether you have a GVM upgrade or not, can have an effect on how much you can tow.

Towing trailers heavier than 3000kg is always going to be a struggle with more than just a driver in a completely un-accessorised vehicle. What it does do is help with managing trailer ball weight so you still have a reasonable payload on the vehicle itself; this is of most benefit for trailers in the 2000 to 2500kg weight spectrum.

Curb Weight GVM Payload GCM Tow Capacity Trailer Trailer Ball
2500kg 3000kg 500kg 6000kg 3500kg 2500kg 250kg


Without a GVM upgrade, the vehicle weighs 2750kg (curb weight plus trailer down ball weight) before adding any 4WD accessories, luggage, fuel or even the driver! Add two adults (~150kg) plus a full tank of fuel (~70kg) and you have just 30kg to spare before you are over GVM (2970kg). In this same scenario with a 300kg GVM upgrade, you would have 330kg of additional payload on the vehicle, and would still be within your GCM limit.

At GVM, your vehicle will weigh 3300kg + a 2500kg trailer sits comfortably 200kg under your vehicles GCM.

WHY DO I NEED A GVM UPGRADE?
Modern vehicles regularly have a payload of anywhere between 500kg – 1000kg, however, with 4WD accessories and heavy trailer down ball weights, it’s not hard to very quickly reach those legal limits.

Increasing your vehicle’s GVM increases its payload, which allows you to kit it out with more of the gear you need to enjoy your 4WDing while staying within the legal limits.

WHO CAN FIT A GVM UPGRADE?
An Old Man Emu GVM upgrade package can be fitted by any ARB store or stockist or authorised ARB service centre. Certification of new, unregistered vehicles, is available at any ARB store or authorised stockist. Certification of registered vehicles must be conducted by a third party engineer. Your ARB store can put you into contact with these suppliers.

GLOSSARY
GROSS VEHICLE MASS

The legal weight limit of your vehicle including all passengers,
luggage, accessories and fuel.

TOWING CAPACITY
The maximum trailer weight (braked) which can be towed behind the vehicle.

TOW BALL WEIGHT
The weight that is applied to the vehicle from the downforce of the tow ball of the trailer. Note, this weight is not removed from the trailer in GCM calculations.

Gross Combined Mass
The weight limit of the vehicle and any trailer combined. GCM is usually lower than the combination of the GVM and the vehicle’s towing capacity.