GoRV - Digital Magazine Issue #78 | Page 50

RV FEATURE
GROSS TRAILER MADNESS
No , Gross Trailer Mass ( GTM ) is not the maximum permissible weight of your caravan . It is a weight rating that refers to the maximum permissible weight that can be ‘ transmitted ’ to the ground by the tyres of the loaded trailer when coupled to a tow vehicle or when supported by a jockey wheel .
It ’ s surprising how often GTM is confused for the van ’ s maximum weight rating – perhaps this is because it uses the word ‘ gross ’.
In any event , Aggregate Trailer Mass ( ATM ) is the rating that refers to the maximum permissible weight of a trailer or caravan , not GTM . Just like with the Tare figure ( an ‘ actual mass ’), the ATM rating also includes the weight being supported by the towbar or jockey wheel .
Payload capacity is a simple equation : ATM minus Tare .
GTM is not the maximum permissible weight of your caravan .
This might sound confusing but let ’ s not complicate things . If you were to place your fully-loaded caravan onto a weigh bridge , on the jockey wheel , the weight being supported by both the jockey wheel and the van ’ s tyres must not exceed the ATM rating engraved on the compliance plate of the caravan .
But how much stuff can you load into your van ? Easy . Simply subtract the Tare ( unladen ) figure from the ATM rating . The answer is your van ’ s payload capacity , in kilograms .
50 \