How to read weight figures and examples
- Ratings are maximum limits, not measurements of your loaded setup. Confirm the exact variant and approved ratings.
- Measure loaded coupling weight. A percentage or the difference between ATM and GTM ratings does not establish today's coupling weight.
- An added load changes both axle reactions according to its position. A change is not a total axle load; use measured starting axle weights and add each load once.
- Combination mass is unhitched loaded vehicle plus total loaded trailer, or the sum of all coupled axle readings. Count coupling mass once.
- Examples and AI suggestions are planning aids, not verified measurements or compliance clearance. Unknown figures require measurement; active weight-distribution hitches and gooseneck arrangements need their own assessment.
Start with the lowest applicable limit
Your vehicle's advertised braked towing capacity is a ceiling, not a complete answer. The usable limit for a particular trip is determined by the first applicable rating reached when the complete loaded combination is assessed.
The limits to check together
Vehicle towing capacity
Confirm the rating for the exact model year, variant, engine, transmission and tow equipment. Do not rely on the highest figure advertised for the model family.
Vehicle GVM and payload
Passengers, accessories, modifications, fuel, cargo and towball download all consume vehicle capacity. A heavily equipped vehicle may have little payload available for the coupling load even when the trailer is below the advertised tow rating.
Gross Combination Mass
GCM limits the mass of the loaded tow vehicle and trailer combination. Transport WA notes that it may be less than the sum of vehicle GVM and towing capacity, so a vehicle at GVM may not be able to tow at its maximum advertised rating.
Front and rear axle ratings
Each axle has its own rating. Rear accessories and towball leverage can make the rear axle the binding limit before GVM is reached.
Towbar and coupling ratings
The vehicle, towbar, towball or coupling can carry different ratings. Use the lowest applicable rating and confirm the approved installation.
Trailer limits
Check ATM, GTM, axle ratings, tyre ratings and the actual loaded mass. ATM is not the same as the weight supported through the trailer tyres when coupled.
Why touring capacity differs from headline towing capacity
The brochure figure does not know how your vehicle is configured. A touring vehicle may carry a bullbar, winch, canopy, drawers, batteries, long-range tank, recovery equipment, occupants and luggage. Every item changes the remaining margin.
The caravan also changes between tare condition and travel condition as water, gas, food, clothing and equipment are added. Use actual or defensible loaded figures rather than relying only on brochure tare.
A simple assessment sequence
- Identify the exact tow vehicle and its verified ratings
- Establish the vehicle's actual loaded mass and axle loads
- Confirm the trailer's ratings and actual loaded mass
- Determine the actual towball download
- Test GVM, GCM, axle, towing and coupling limits together
- Keep a sensible operating margin for uncertainty and load changes
- Verify the final setup by weighing it in travel condition
Example of competing limits
Assume a vehicle is advertised to tow 3,500 kg. Its loaded mass before hitching leaves 280 kg below GVM, while the caravan applies 300 kg at the towball.
The combination is already over the vehicle's nominal GVM capacity even though the caravan could remain below the advertised towing limit. Rear-axle leverage may create a separate constraint, and GCM may reduce the allowable combination further.
The controlling result is the first limit exceeded, not the largest number in the brochure.
When to obtain a detailed assessment
A detailed assessment is useful before buying a vehicle or caravan, fitting major accessories, choosing a GVM or GCM modification pathway, or travelling with narrow calculated margins.
ClearPath can bring the relevant vehicle, trailer and load assumptions into one report, identify the pressure points and list what must be verified. Final compliance, engineering certification and measured weights remain separate where required.