If you’re wondering how much your caravan, camper trailer or entire towing combination weighs, empty or loaded, public weighbridges are an easy solution. They can also be used to separately record the weight of the axle/s to ensure compliance with transport regulations.
Understanding the weight of your rig is of vital importance to any owner of a caravan or camper – for safety and security, and to avoid penalties. Obviously, the onus is on the driver to ensure the weight of the van doesn’t exceed the capacity of the tow vehicle and strict regulations apply to towing with illegal weights.
It should also be noted that if you haven’t independently verified the weight of your loaded van and can prove it was within acceptable limits and you’re involved in an accident (regardless of fault), your insurance is looking extremely shaky and any claim is likely to be rejected!
The only way to really know is to take your rig – all loaded up, ready to tour – to a public weighbridge and have it weighed.
HOW DO I FIND A WEIGHBRIDGE?
Public weighbridges are located all over the country, as they are commonly used by trucks and other big rigs as well. Details of licensed public weighbridges can be found via a quick internet search, on the Australian Government’s National Measurement Institute (NMI) website www.measurement.gov.au or at www.publicweighbridge.com.au
The majority of public weighbridges are generally found at dedicated weighbridge-only sites, often along major highways, and at local council depots or industrial estates.
Some weighbridges are free and self-service, many with external digital displays. Non-commercial drivers can also use these sites to check the weight of their vehicle and any trailer, boat or caravan etc.
Whether it’s brand-new or second-hand, putting your van over a weighbridge is an insurance policy in itself and arguably the best $30 or so (per weigh) you’ll spend in the RV industry.
HOW TO USE A WEIGHBRIDGE
Maintaining a well-balanced rig (across all axle groups) is just as critical as not exceeding weight limits. This increases safety, stability and reduces maintenance on the tow vehicle and caravan. And, in terms of accurately calculating payload, it’s also advisable to weigh your van unladen as well as fully loaded.
Weighbridges are relatively easy to use and while at the weighbridge it’s essential to consider at least four important caravan weights: Aggregate Trailer Mass (ATM), Gross Trailer Mass (GTM), Tare and Tow Ball Maximum.
The ATM is the most your caravan can weigh, with everything in and on it, as it stands, unhitched. It is the weight that each wheel and the jockey wheel impose on the ground all added together, at the very most. The maximum allowable ATM will have been set by your caravan manufacturer and stamped on the compliance plate.
The GTM is the maximum weight that the caravan wheels can collectively impose on the ground. In other words, the wheels’ share of the ATM figure (remembering that the ATM is the coupling download weight and the weight of the wheels imposed on the ground added together).
Tare mass is the weight of the caravan as it leaves the factory, without water in the tanks, any gas in the cylinders, any luggage or personal effects whatsoever. It is also without the weight of dealer-fitted extras, such as an awning, air-conditioner and so on.
This will also be stamped on the compliance plate.
And towball mass can be calculated by subtracting GTM from ATM.
You can record the weight of a caravan on the weighbridge by winding down the jockey wheel and then disconnecting it from the tow vehicle. However the jockey wheel must be on the same metal pad as the caravan, with the tow vehicle clear of the same deck.
When measuring ball weight (i.e. vertical weight the caravan is exerting on the towbar), position the tow vehicle (connected to its caravan but with all of its wheels on a separate deck to the caravan wheels) and record the weight of the tow vehicle. Then disconnect the caravan and solely record the weight of the tow vehicle. The differential is the ball weight.
MEET THE AUTHOR
Peter Quilty
With more than 30 years’ journalistic experience, Peter’s brief predominantly centres on editorial reviews for Caravan World and CamperTrailer Australia magazines.
A relative late starter to the trials and tribulations of the RV industry, Peter has been making up for lost time caravanning and camping with his family around Victoria. Initially, Gippsland was the primary stamping ground free camping in idyllic bush settings such as Dargo and Licola, beside the Wonnangatta and Macalister rivers respectively. Other favourite haunts also became ensconced on the family camping itinerary – Jamieson in Victoria’s High Country, Whitfield in the King Valley, Princetown on the Great Ocean Road, and Bright in the Ovens Valley.