Understanding the weight of your RV is critical for safety and stability on the road, yet it is often neglected. Recent studies indicate that 50% to 90% of caravans were overweight! Despite the high numbers, police and State transport bodies have been choosing to educate rather than issue fines, but we don’t know how long this can occur.
The first step to knowing your weights is to understand the lingo:
Weight Glossary
Tare Weight
Tare Weight represents the unladen weight of the vehicle including all engine fluids and a 10 per cent fuel reserve. It is important to note that this may not include dealer inclusions or optional fittings at the time of purchase.
Gross Vehicle Mass (GVM)
Gross Vehicle Mass is specified by the manufacturer and is the maximum legal loaded mass of the vehicle. It includes the weight of the car, fuel, vehicle payload, all passengers, plus tow ball weight if towing.
Gross Combination Mass (GCM)
Gross Combination Mass is the total permissible weight of the loaded vehicle and caravan together and is specified by the manufacturer.
Aggregate Trailer Mass (ATM)
Aggregate Trailer Mass is the maximum total weight of the caravan or camper trailer. This is specified by the manufacturer and includes the tow ball weight.
Payload
Payload refers to the total weight you can add to your vehicle. This includes fresh and wastewater, gas bottles, personal items, clothes, bedding, food etc. It can also include optional extras and aftermarket modifications such as awnings and driving lights. If you are towing, your tow ball weight must be included in your vehicle’s payload.
You can calculate your caravan or camper trailer payload by subtracting the Tare Mass from the Aggregate Trailer Mass (ATM).
Tow Ball Weight
Tow Ball Weight, also referred to as tow ball mass, is the weight pushing down on the tow ball by the coupling of the RV being towed.
Campervan and Motorhome Weight
Knowing your motorhome’s weight is straightforward yet crucial. Keeping within weight limits ensures safety and stability on the road. You also need to know your vehicle weight to ensure you have the correct licence for your RV. Key weights include Tare Weight, GVM, and Payload.
Check the compliance plate for Tare Weight and GVM, and subtract the Tare Weight from the GVM to calculate Payload. This will give you the carrying capacity for your RV. However, you still need to visit a weighbridge or portable weigh station with all gear and passengers loaded, to know your exact weights and ensure you are within limits.
If towing, consider the motorhome’s Towing Capacity, Tow Ball Mass, and GCM as per the manufacturer’s specifications.
Caravan and Camper Trailer Weight
Accurately measuring your caravan or camper trailer combination weights is vital as both total weight and distribution affect towing stability and braking.
If you are new to RVing and shopping for your first combination, it is important to do your research to make sure you consider the tow vehicle towing capacity, trailer weight, and payload requirements.
Manufacturers will specify key weight limits. These can be found on the vehicle or trailer compliance plates or check your owner’s manual.
You need to ensure that your vehicles Towing Capacity (Braked) is higher than your Gross Trailer Mass. From here, there are four weight limits you need to check that you are within limits.
You will need to have your vehicle weighed to ensure that you have not exceeded your payload. We recommend visiting a public weigh bridge or using a mobile weigh station.
Fifth-Wheeler Weight
When calculating the tow capacity of a fifth-wheeler, consider the GVM and GCM. Typically, 20% of the fifth-wheeler weight is carried by the tow vehicle, but it must not exceed the legal payload allowance. Calculate payload by subtracting Tare Weight from GVM.
Fifth-wheelers offer benefits like greater towing stability and larger RV space but they do impact vehicle payload.
I’ve weighed in, now what?
Once you know your weights, you need to keep in mind that this will change depending on how much you load into your vehicle! As you travel your weights will vary as you will inevitably add and remove items along the way. If you are near your weight limits you will need to be extra conscious of what you are carrying in your vehicle and may need to reconsider stocking up on supplies for your trip.
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