Stay safe, legal and confident on the road
If you tow a caravan or plan to, understanding weight ratings isn’t just for compliance—it’s essential for safety. Terms like Tare, ATM, GVM, and GCM get thrown around often, and they can be confusing at first. But knowing what they mean—and how they affect your towing setup—can help prevent serious problems on the road.
This guide breaks down each term in plain English, so you can make informed choices when towing or loading your caravan.
Tare Weight: What Your Caravan Weighs Empty
Tare is the weight of the caravan as it comes off the factory floor. It includes all standard fittings, like cupboards, the fridge, oven, water tanks (empty), and tyres. It does not include any personal items, gas bottles, water, or luggage.
Understanding Tare is important because it gives you a starting point. Any gear you add—camping chairs, food, water, and clothes—increases the total weight. If you go over certain limits, you risk being unsafe or unroadworthy.
ATM: The Maximum Weight Your Caravan Can Legally Be
ATM stands for Aggregate Trailer Mass. It’s the total legal weight of the caravan when fully loaded. That includes everything: water in the tanks, gas bottles, tools, food, and anything else stored inside or attached to the van.
The difference between your ATM and Tare Weight is how much you can safely carry—this is known as payload. If your caravan exceeds its ATM, it becomes dangerous to tow and may void your insurance.
Always weigh your caravan loaded before a trip to make sure it stays within this limit. Public weighbridges are ideal for checking this.
GVM: What Your Tow Vehicle Can Carry
GVM, or Gross Vehicle Mass, refers to your car’s maximum weight when fully loaded. This includes the weight of the vehicle itself, passengers, fuel, luggage, and the tow ball weight of the caravan.
Many people overload their tow vehicle without realising it, especially with roof racks, extra fuel tanks or tools. Going over the GVM can put stress on brakes, suspension, and tyres—not to mention getting you in trouble during roadside checks.
GCM: Combined Weight of Vehicle and Caravan
GCM means Gross Combination Mass. It’s the total allowed weight of your loaded vehicle plus your loaded caravan. This is the key number for people towing, because even if your vehicle and van are within their own limits individually, they may exceed the GCM together.
Staying under the GCM ensures your engine, transmission, and braking system can handle the load safely. It’s also essential for legal compliance.
Why These Numbers Matter
Ignoring weight limits can lead to poor handling, increased stopping distances, and higher wear and tear on both your tow vehicle and caravan. It’s also a major factor in insurance claims and roadside safety inspections.
By knowing your Tare, ATM, GVM and GCM, you’re taking control of your safety and protecting your investment.
Need Help Weighing Up Your Setup?
If you’re unsure whether your towing setup is within safe limits—or you just want expert advice on how to load and balance your caravan correctly—AllBrand Caravan Services can help.
We check weights, towing compliance, and vehicle setups to ensure everything’s safe and legal before you hit the road.
📍 101 Connaught Street, Sandgate QLD 4017
📞 07 3869 2969
📧 info@allbrandcs.com.au
Travel with confidence. Talk to the team at AllBrand Caravan Services today.
Useful Resources:
- Read more from The Caravan Industry Association of Australia’s Complete guide to everything towing in Australia
