The combined weight of the towing vehicle and any trailer while coupled together.
Gross Vehicle Mass (GVM):
The weight transferred to the ground through the wheels of a fully laden vehicle. Including the trailer attached if towing to ensure weight transferred through the tow hitch is included in calculations.
Tow Ball Mass (TBM):
The weight imposed on the tow vehicle’s tow hitch (ball or other type) by the coupling of the trailer onto the tow bar.
Recommended to be 8–12% of ATM.
Gross Trailer Mass (GTM):
The weight transferred to the ground by the wheels of the trailer when coupled to a vehicle.
Aggregate Trailer Mass:
The weight of the laden trailer including the tow ball weight.
