Defined by Vehicle Manufacturer
Gross Vehicle Mass “GVM” Weight transmitted by all tow vehicle axles to the ground
Front Axle Capacity “FAC” Weight on tow vehicle front axle
Rear Axle Capacity “RAC” Weight on tow vehicle rear axle
Towing Capacity Typically stated at ATM (see trailer definitions)
Towbar Down Force “TDF” Weight transmitted from trailer to vehicle towbar
Gross Combination Mass “GCM” Sum of all axle loads; vehicle and trailer
These are defined by the vehicle manufacturer and maybe limited by the capacity of axles, engine and drivetrain limitations and vehicle gradability.
MANUFACTURER - the name of the person or company who accepts responsibility for compliance with the Australian Design Rules and to whom the ‘Compliance Plate’ approval certificate is issued.
This definition of “Manufacturer” encompasses First Stage Manufacturers and all Second Stage Manufacturers for which a federally approved compliance plate has been issued for the vehicle. As defined by Vehicle Standards (Australian Design Rule – Definitions and Vehicle Categories) 2005 - dated 14/5/2016.
Defined by Trailer Manufacturer
Gross Trailer Mass “GTM” Weight transmitted by all trailer axles to the ground
Aggregate Trailer Mass “ATM” Trailer mass including tow ball down force on tow vehicle
These are defined by the trailer manufacturer and maybe limited by the capacity of axles, capacity of suspension and the capacity of the tyres.
The towing vehicle and trailer must adhere to these limits at all times. This is to ensure the vehicle operator remains within safety and legal requirements in all vehicle loading and towing situations. This ensures insurance policies remain valid and also leads to a stable towing experience with a properly balanced vehicle-trailer combination.
1.1. Vehicle Capacity Definition
Vehicles are limited by:
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Front Axle Capacity (FAC)
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Rear Axle Capacity (RAC)
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Gross Vehicle Mass (GVM)
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Gross Combination Mass (GCM)
The Lovells Front Axle Capacity CANNOT BE EXCEEDED.
The Lovells Rear Axle Capacity CANNOT BE EXCEEDED.
The Lovells Gross Vehicle Mass is inclusive of the following and CANNOT BE EXCEEDED:
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Vehicle Tare Mass
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Passengers
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Cargo
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Fuel
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Towbar Down Force
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Any other fitted accessories
GVM = Front Axle Tare + Rear Axle Tare + PAX + Cargo + TDF + Accessories
2. Definitions Summary
This outlines, in simple terms, the definitions of critical concepts to be considered when towing a trailer with a laden vehicle.
At all times, the road going tow vehicle and trailer must be within manufacture and Road Authority mass and axle limits. This means at all times:
The Front Axle Capacity CANNOT BE EXCEEDED.
The Rear Axle Capacity CANNOT BE EXCEEDED.
The GVM (Gross Vehicle Mass) CANNOT BE EXCEEDED.
The GCM CANNOT BE EXCEEDED.
The ATM CANNOT BE EXCEEDED.
The GTM CANNOT BE EXCEEDED.
1.2. Gross Combination/Combined Mass Definition
The Gross Combination/Combined Mass, GCM, is defined as follows:
GCM = GVM – TDF + ATM
In simple terms it is the sum of all vehicle and trailer axle loads transmitted to the ground.
The GCM CANNOT BE EXCEEDED.
1.3. Trailer Capacity Definition
Trailers and towbars are rated by Aggregate Trailer Mass (ATM) which is the total weight of the trailer.
The ATM is defined in simple terms as All The Trailer Mass. It is inclusive of the loads on the axles or GTM, and the load on the tow coupling or TDF.
The axle loads on the trailer are defined as Gross Trailer Mass (GTM).
The trailer imposes a load on the tow vehicle defined as Towbar Down Force (TDF).
ATM = GTM + TDF
The ATM CANNOT BE EXCEEDED.
The GTM CANNOT BE EXCEEDED.
