The Ultimate Caravan Towing Weight Guide
Towing a caravan in Australia is one of the best ways to see the country, but the technical side of weights can be a nightmare. If you don't get your numbers right, you're not just risking a fine—you're risking your safety and your insurance.
Why Weights Matter
Modern caravans are heavier than ever, and police are increasingly setting up roadside weighing stations. Being overweight by even 50kg can result in an "unroadworthy" notice and potentially void your insurance if you're in an accident.
💡 Quick Tip
Never trust the manufacturer's plate blindly for your payload. Always head to a public weighbridge once you've loaded your water, gas, and gear.
The Key Definitions
GVM (Gross Vehicle Mass)
This is the maximum weight your vehicle can carry. This includes the car itself, fuel, passengers, your bullbar, luggage, and most importantly: the Tow Ball Mass of the caravan.
ATM (Aggregate Trailer Mass)
This is the maximum weight your caravan can weigh when it is fully loaded and NOT hitched to your car. Think of this as the caravan's personal GVM.
GCM (Gross Combined Mass)
This is the big one. It's the maximum total weight of your car and caravan combined. Even if your car is under its GVM and your van is under its ATM, you might still exceed your GCM.
Check Your Own Weights
Don't guess the math. Use our free, interactive tool to see if your setup is legal.
Open Towing Calculator 🧮The Hidden Trap: Rear Axle Load
Often overlooked, your vehicle's rear axle has its own weight limit. When you put a 300kg caravan on the tow ball, it doesn't just add 300kg to the back. Because the ball is behind the axle, it acts like a lever (a "see-saw" effect), which actually takes weight off your front tyres and pushes down even harder on the rear ones.
Our calculator includes a Lever Effect calculation to help you ensure you aren't overloading your rear suspension and tyres.
Summary Checklist
- Check your vehicle's GCM (Car + Van total)
- Check your vehicle's GVM (Car total)
- Check your caravan's ATM (Van total)
- Measure your Tow Ball Mass (usually 7-10% of van weight)
- Ensure your Rear Axle isn't overloaded by the lever effect