GVM meaning: GVM and GCM explained, and how to stay under them

GVM: the vehicle

Start from the kerb weight on the spec sheet and add everything you put in or on it: people, luggage, fridge, water, canopy, tray, bar work, roof racks, second battery, and the weight the trailer puts on the tow ball. That total must stay under GVM. The difference between kerb weight and GVM is the payload.

GCM: the whole combination

Add the loaded vehicle to the loaded trailer. On many dual-cab utes rated to tow 3,500 kg, GCM is less than GVM plus 3,500 kg, so towing the full rating means the ute must carry less. That is why towing at the full rating leaves only a few hundred kilos of payload on many popular utes. See the vehicle table.

Does GVM include the trailer?

Only the part of it on the tow ball. The rest of the trailer counts towards GCM, not GVM.

What does 4.5 tonnes GVM mean?

A standard car licence covers vehicles up to 4,500 kg GVM. Above that, a vehicle is classed as a light rigid truck and needs a heavier licence class.

Where to find your GVM and GCM

The GVM is on the vehicle's compliance plate or modification plate, usually in the door jamb or engine bay, and in the owner's handbook. The GCM is in the handbook and the manufacturer's specifications. If a vehicle has had a GVM upgrade, the new figure appears on a modification plate and in the registration record. Always use the figure for your exact vehicle, model year and variant.

Payload explained

Payload is the difference between the GVM and the vehicle's kerb weight: the weight of everything you can add. Kerb weight usually includes a full tank of fuel and standard equipment but not accessories, people or cargo. Many dual-cab utes have a payload of around a tonne on paper, but bull bars, canopies, drawers and other accessories reduce what is left before anyone gets in.

How to check you are under GVM and GCM

The only sure way is to weigh. Load the vehicle and trailer as you will travel, with people, water, fuel and gear, and visit a public weighbridge. Weigh the vehicle alone with the trailer attached (its axles only) to compare with GVM, then the whole combination for GCM, and the trailer alone for its ATM. Some caravan weighing services come to you and weigh each axle and wheel, which also shows if the load is uneven.

What happens if you are over

Driving over GVM or GCM is illegal and unsafe: brakes, suspension, tyres and steering are designed for the rated weights. Police and transport inspectors can fine drivers and can direct an overloaded vehicle off the road. Insurers may refuse or reduce a claim if an overloaded vehicle was involved in a crash. And an overloaded vehicle wears out faster.

GVM upgrades

A GVM upgrade raises the legal maximum loaded weight of a vehicle, usually through engineered suspension and sometimes brake or tyre changes, certified to Australian rules. Upgrades done before the vehicle is first registered are typically simpler than upgrades after registration. An upgrade does not always increase the GCM, so it may give more payload when not towing, but little or no extra when towing at the full rating.

ATM and GTM: the trailer side

Trailers have their own limits. ATM (aggregate trailer mass) is the most the loaded trailer may weigh, including the weight on the tow ball. GTM (gross trailer mass) is the most the trailer's axles may carry. The loaded trailer must stay under both, and its weight counts towards the tow vehicle's braked towing capacity and GCM.

A simple example

Suppose a ute has a GVM of 3,200 kg and a kerb weight of 2,200 kg, so 1,000 kg of payload. Fit a bull bar, canopy and drawers totalling 200 kg, add two adults at 170 kg and 150 kg of gear, and put 250 kg of tow ball weight on the back. That is 770 kg, leaving 230 kg spare under GVM. Then check GCM: the loaded ute (2,970 kg) plus a 2,800 kg caravan is 5,770 kg, which must be under the ute's GCM. These are example figures only; use your own vehicle's.

Common GVM mistakes

1. Forgetting that tow ball weight counts towards GVM.
2. Using the brochure kerb weight, which leaves out accessories already fitted.
3. Assuming a GVM upgrade also raises the GCM.
4. Loading the tray or canopy behind the rear axle, which overloads it even under GVM.
5. Never weighing, and guessing instead.

GVM, GCM and your licence

A car licence covers vehicles up to 4,500 kg GVM, so an upgraded ute that goes over that figure may need a light rigid licence. Check the licence class before upgrading.

Quick reference

• GVM: the loaded vehicle, including tow ball weight.
• GCM: the loaded vehicle plus the loaded trailer.
• Payload: GVM minus kerb weight.
• ATM: the loaded trailer.
• Tow ball weight: the trailer's weight on the ball, counted in GVM.

Why GVM matters for safety

A vehicle over its GVM brakes less effectively, especially when hot, its tyres run hotter and are more likely to fail, and its suspension can bottom out on bumps, upsetting the steering. In a crash, an overloaded vehicle carries more energy into the impact. Those are the reasons the limits exist, and why staying under them matters even when no one is checking.

How GVM is set

The vehicle maker sets the GVM after testing the vehicle's brakes, suspension, axles, tyres and chassis at that weight, and it is certified as part of the vehicle's compliance with the Australian Design Rules. That is why it can only be raised through an engineered, certified upgrade, not simply by fitting stronger springs. The GCM is set by the maker in the same way, based on the drivetrain, cooling, brakes and chassis strength when the vehicle is towing a loaded trailer.

Checking a second-hand vehicle

When buying a used ute or van, check the compliance plate and any modification plate, ask whether a GVM upgrade has been fitted and whether its paperwork and registration record match, and weigh the vehicle with its accessories to see how much payload remains for your needs.

Roof loads and GVM

Roof racks, roof tents, kayaks and gear on the roof all count towards GVM, and the roof itself has a separate load rating set by the vehicle maker, often much lower than people expect. Check both before loading the roof, and keep heavy items low in the vehicle where they affect handling least.

Common questions