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Towing and weights
GVM and GCM: what they mean and how to stay under them
GVM is the most your vehicle may weigh, loaded. GCM is the most the vehicle and trailer may weigh together. Both are on the compliance plate and in the handbook, and both are legal limits.
Hitch & HighwayChecked 3 October 20262 min read
Quick answer
GVM (gross vehicle mass) is the maximum a vehicle may weigh when loaded: its kerb weight plus people, gear, accessories and any tow ball weight. GCM (gross combination mass) is the maximum the vehicle and its loaded trailer may weigh together. Exceeding either is illegal and can affect insurance.
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.
Common questions
What is the difference between GVM and GCM?
GVM is the maximum loaded weight of the vehicle alone. GCM is the maximum combined weight of the vehicle and trailer together.
How do I calculate GVM?
You don't calculate the limit, it is on the compliance plate. To check you are under it, add people, gear, accessories and tow ball weight to the kerb weight, or weigh the loaded vehicle at a weighbridge.
Does GVM include a trailer?
Only the weight the trailer puts on the tow ball. The rest of the trailer counts towards GCM.
Do you include trailer weight when towing?
Yes, in GCM: the loaded trailer plus the loaded vehicle must stay under the vehicle's GCM.
Sources
Hitch & Highway is a towing and van gear store in preparation and is not trading yet.