weights explained
Gross Vehicle Mass - GVM
Weight of your vehicle when fully loaded. This is the maximum your vehicle can weigh when fully loaded as specified by the manufacturer. GVM is the Kerb Mass (standard vehicle with full tank of fuel) plus all accessories (bull bars, dual batteries, roof racks etc) and payload.
Most importantly, if you're towing something, the GVM also includes the tow ball mass from your trailer.
Tow Ball Mass - TBM
Tow ball mass (or tow ball load) is the maximum mass allowed to be put on the tow ball of the towing vehicle. You can find the tow ball mass capacity in your coupling manufacturer's handbook. TBM should be around 10-15% of the Gross Trailer Mass (GTM)
Gross Combined Mass - GCM
The GCM is the maximum loaded weight of the towing vehicle and any trailer or caravan being towed while driving on the road.
GCM = GTM + GVM
Aggregate Trailer Mass - ATM
ATM is the total mass of the trailer when carrying the maximum load recommended by the manufacturer. The ATM is generally measured with the caravan unhitched from your towing vehicle and resting on its jockey wheel. ATM = Tare Mass + Payload
Gross Trailer Mass (GTM)
Gross Trailer Mass (GTM) is the maximum mass recommended by the manufacturer of your fully loaded caravan when it is hitched to your tow vehicle. The GTM of the caravan is transmitted to the ground by only the caravan tyres and excludes the mass distributed to the towing vehicle through the coupling. GTM = ATM - TBM
TARE MASS
Tare Mass is the weight of the Caravan or Trailer straight off the production line. This is the total weight of an empty caravan/trailer. It does not include, luggage, water or gas bottles or additional accessories such as solar panels, batteries, bike racks, toolbox, BBQ etc.
PAYLOAD
Payload is defined as the total combined weight of all items, that can be loaded in the caravan.