atm vsThe difference between ATM and GTM – 200kg in this case – is the amount being supported by the jockey wheel or towbar of the tow vehicle, otherwise known as ball weht. Therefore, payload capacity of a trailer isIn Australia and Europe, the ATM and the GTM can be the same number. 3500kg at GTM is not the weth but a measurement of D-value. Payload Capacity. Payload is the trailer’s carrying