Gross combination mass (GCM)

Gross combination mass is the maximum combined weight of a vehicle plus everything it tows, including the trailers and their loads, as rated by the manufacturer.

GCM is the limit that catches tow-heavy fleets: a ute can be under its GVM and still be illegal because the ute plus loaded trailer exceeds its GCM.

Exceeding rated mass is a safety issue, an insurance issue and a Chain of Responsibility issue, so fleets that tow should know both numbers for every combination they run.

Last updated 10 July 2026. General information, not tax or legal advice.