Understanding Motorhome Weights and Limits
When it comes to selecting a motorhome, weight is a hugely important consideration.
When buying a regular car, it’s not really something we think about, but when it comes to RVs, the weight of the vehicle may dictate what kind of licence you need to drive it. RV manufacturers build their RVs with components, such as tyres, axles and suspension, that are made to handle a certain amount of weight. They also perform extensive testing to ensure these weights are correct. It is important not to overload your RV as staying within the manufacturer-specified weight limit is a legal requirement. Being pulled over to be randomly weighed by state road authorities or getting into an accident with an overloaded RV can result in serious legal issues and your insurance will be void. Not to mention, overloading can result in excess wear and tear or premature failure.
The Figures
There are several figures of which to be aware that define how heavy your motorhome can be – this includes the weight of the vehicle, its contents and additional fittings and features. Payload is the total weight you can load into your RV, including extra appliances, clothes, bedding, food and water and any other creature comforts. Choosing to fit aftermarket modifications such as driving lights and awnings also take away from your payload. Calculating your motorhome’s payload is easy, simply subtract the vehicle’s tare weight from GVM (gross vehicle mass). And remember, things such as awnings, spare tyres, storage boxes and extra tanks can dramatically reduce payloads.
Tare weight is the weight of the vehicle as it leaves the manufacturer, including all engine fluids and a 10 per cent fuel reserve. Please note water tanks are empty at this point. It’s important to find out from the manufacturer whether dealer inclusions and option fittings are included in the tare weight at the time of purchase. All buyers are advised to verify the figure on the compliance plate by requesting the RV be weighed in their presence on a certified weighbridge prior to finalising purchase.
Gross Vehicle Mass (GVM) is the most your vehicle can weigh, including fuel, water and anything else inside – even the driver and passengers. To ensure you’re within the allowed GVM, load up everything you wish to take on the road into your RV, fill the tanks and drive to your nearest weighbridge. Knowing is better than assuming and could save you from an accident.
Towing Weight
If you’re towing a trailer, caravan or vehicle behind your motorhome, there are further weight restrictions to be aware of. There are three figures which denote the towing weight:
BRAKED – refers to how much a vehicle can tow when trailer (or flat-towed vehicle) brakes are in use
UNBRAKED – legally restricted to 750kg
COUPLING DOWNLOAD AMOUNT — this specifies the amount of downward force that can be exerted on a towball. (You may have heard that this will be 10 per cent of the overall towing capacity, but that isn’t always true so it’s best to check.)
Finally, there’s the gross combination mass (GCM). This is how much the entire rig weighs (vehicle, trailer and payload).
Towing a Second Vehicle
There are some remote areas where getting an RV in is virtually impossible, so often motorhome owners tow a small car or 4WD to use to go further offroad after they’ve set up base camp. There are three ways to do this:
FLAT TOWING – the simplest method, is where all four of the vehicle’s wheels are on the ground and it’s simply being pulled along. For this method, the vehicle must be connected via an A-frame to the front of its structural frame, there needs to be an independent braking system in operation and brake lights must be connected. The laws regarding flat towing vary slightly from state to state so your setup must comply to the rules of the state in which it’s registered. (Not all cars can be flat towed.)
DOLLY TOWING – a good alternative for vehicles that cannot be flat towed. A tow dolly is a small trailer that holds the front wheels off the ground while the back wheels remain on the road, allowing the drivetrain of a front-wheel drive vehicle to remain motionless. Dollys are equipped with their own brakes and they’re simple to use.
TRAILER TOWING – often the safest method, is when the vehicle is loaded onto a trailer so that none of its wheels are touching the ground. In this instance, regular trailer regulations apply, including break requirements and so on.
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