How to Weigh Your Caravan
Author: Tahlia Maynard Date Posted:6 February 2017
Ensuring your caravan and towing vehicle don't exceed their specified tow weights is one of the most important things to keep in mind for all caravanners. Here's a shortcut to all the acronyms you need to know as well as how you can weigh your rig.
Before you can hitch up your new caravan and head off into your first outback or beach side adventure, it is important to invest some time in understanding the issue of caravan weight, why it is something you can’t afford to ignore and how exactly you should go about measuring it.
The Importance of Caravan Weight
Just like any other vehicle, caravans are built to sustain a certain maximum weight. What’s even more important to note is that your towing vehicle also has its own weight limits. With a fully loaded caravan hitched to it, your vehicle will be handling a lot more weight than it typically does in isolation. This can make controlling your caravan quite a task in meandering terrain, windy conditions, and in any kind of situation that requires sudden braking. Too much weight can also compromise your car’s performance in terms of fuel efficiency and air conditioning. Last but not the least, exceeding the weight limits set by your car’s manufacturer can land you in legal trouble. To avoid all of this, it is important to weigh your caravan (and your entire rig) correctly, before leaving for your next holiday.
Weights You Should Know About
Gross Combination Mass (GCM) is the total weight of your rig (everything loaded and coupled).
Gross Vehicle Mass (GVM) is the maximum permissible weight of your towing vehicle when loaded. This is specified by the vehicle’s manufacturer.
Nose Weight is the maximum weight that your caravan can apply to your vehicle’s tow ball. This is specified by the vehicle’s manufacturer. You can use a measuring gauge (manual or digital) to measure the actual nose weight of your caravan at any given point in time, to make sure it’s within your vehicle’s limits.
Aggregate Trailer Mass (ATM) is the maximum permissible weight of your caravan when loaded, and without being hitched to your towing vehicle. This is specified by the caravan’s manufacturer.
Gross Trailer Mass is the actual weight of your loaded caravan, at any given point in time, without being hitched to your towing vehicle.
Safety guidelines in Australia recommend that a loaded towing vehicle should weigh 30% more than the loaded caravan hitched to it. This roughly implies that the Gross Trailer Mass should be less than 77% of the laden weight of your towing vehicle.
Weighing your caravan/rig:
Because there is no household device for weighing your caravan at home, there are facilities in place known as weighbridges. These are designed to help vehicle owners weigh their cars, caravans and entire rigs, to ascertain their weights and payloads. What you essentially need to do is drive up to a weighbridge near you, pay the per-use fee (typically around $30), and move your vehicle or rig on to their specially made scales set into the ground. The idea is simple: weigh your empty vehicle or caravan to ascertain its tare weight; take it back to the weighbridge when fully loaded for another reading; subtract the two to calculate its payload. But what makes modern weighbridges a blessing for caravan owners is their ability to give you multiple readings at once.
How to Use a Weighbridge
The typical modern weighbridge has multiple pads making up its weighing area. These are laid out in a linear fashion, so that when you drive your rig up to the weighing area, each part of the set-up (vehicle, caravan, and the hitching system between them) is exerting its weight on a different pad. Adding up the readings from the different pads will give you the Gross Combination Mass of your rig. Ideally, this should be less than the sum of the Gross Vehicle Mass (of your loaded car) and the Aggregate Trailer Mass (of your loaded caravan).
To measure the weights of your loaded vehicle or loaded caravan, disengage the hitch and take the reading from the specific weighing pad that the vehicle or caravan is on. In case a part of your vehicle or caravan is on another weighing pad, just add up the readings on all the pads involved to get its weight.
And that’s it! Weighbridges make the task of weighing your caravan or rig simple and intuitive. So, Google the location of your nearest public weighbridge, weigh your caravan correctly, and enjoy a safe and worry-free caravanning holiday.