The unladen weight of the complete new trailer as delivered from the factory
(including any factory fitted options)
We weigh every van as it comes off our assembly line to establish the tare mass which is marked on the van.
Each van is weighed with:
The weight imposed on the tow vehicle’s tow ball by the coupling.
Towball Mass Tare:
Unladen as from factory
Towball Mass Loaded Actual:
With load on board (where items are loaded in the van will impact on actual towball mass)
Towball Mass Maximum Permissible: Maximum allowed with caravan loaded as rated by manufacturer
ATM - Aggregate Trailer Mass
The total laden weight of a trailer, which includes the tow ball mass and whatever you add as payload (eg. water, gas, luggage). The ATM is specified by the trailer manufacturer and must not be exceeded.
The payload is worked out by deducting the “Tare Mass” from the “ATM”. It must not be exceeded under any circumstances. Safety, insurance & warranty my be affected if the specified payload is exceeded.
GTM - Gross Trailer Mass
The total permissable mass which includes whatever you add as payload (eg. water, gas & luggage) that can be supported by the wheels of a trailer. This does not include the mass supported by the tow ball.
GVM - Gross Vehicle Mass
The GVM is the maximum allowable total mass of a fully loaded motor vehicle. It consists of the tare mass of the vehicle plus the load (including passengers and the towball download).
GCM - Gross Combination Mass
The GCM is the rating provided by the manufacturer of the tow vehicle. The maximum
laden mass of a motor vehicle plus the maximum laden weight of an attached trailer is not permitted to exceed the GCM rating.
Source; Adapted from The National Caravan & RV Towing Guide