Overweight caravan epidemic spreads

A Melbourne-based mobile weighing specialist has fueled growing concerns that the number of overweight caravans has risen to epidemic proportions.

Despite operating his mobile caravan weighing service for less than a year, Ian McCallum from Weigh Station can back up existing evidence that suggests that more than half of all caravans on the road are overweight.

“Of the six compliance metrics we work with – GVM, GCM, braked towing capacity, GTM, ATM, and towball mass -- at this stage around about 50 per cent  (of the rigs we’ve weighed) fail on one or more of those metrics,” McCallum told caravancampingsales.

“The biggest issue we have with (caravan rigs) is ATM; they might be borderline on their towball mass, but once you add in the GTM (Gross Trailer Mass), they often exceed the van’s ATM (Aggregrate Trailer Mass).”

Weigh Station usually weighs a caravan rig when fully loaded up with water and gear, and often just prior to setting off on a trip.

“A major issue we find is that there’s limited payload in many of the caravans,” he explained. “They’re mostly 300kg to 400kg, which just isn’t enough payload especially when you consider that it’s often the case that any extra accessories fitted at the dealer are not included in the plated Tare weight on the van.

“On some occasions a customer has discovered a day before leaving that they’re overweight, and have had to move 200kg or so from their tow vehicle to the van, or the other way, or just leave some items at home to lighten the load.

“The worst I’ve seen so far is one rig that was 480kg over on their Gross Combination Mass… in fact, the only metric in which they were under was Gross Trailer Mass; everything else was over by hundreds of kilograms, including 421kg ball weight!”

The high proportion of over-loading issues recorded by Melbourne’s Weigh Station backs up similar results reported in recent times, including a Victorian police blitz in 2017 as well as the experiences of another mobile weighing specialist based in Queensland.

McCallum said the issues around overweight caravans are much more serious than just having an unroadworthy vehicle.

“If your caravan is overweight, you could be compromising your insurance cover and in some states, heavy fines and loss of demerit points apply for offences relating to being overweight,” he said.

“The safety of your family is also directly affected by the weight compliance and subsequent handling of your caravan.”

Weigh Station has also recorded serious overloading issues with four-wheel drive vehicles, often laden with after-market accessories.

“The worst example I’ve had so far was a Nissan Patrol. Even after he had removed the canopy, spare tyre and water that the vehicle normally carried, it was still 200kg over the maximum GVM for that vehicle,” he said.

Working with aftermarket 4WD accessory companies, Weigh Station has helped identify vehicles that may require GVM upgrades after the fitment of heavy accessories like bullbars, snorkels, winches, roof racks and underbody protection.

Covering most of Victoria, Weigh Station charges $199 for a tow vehicle and trailer, and $99 for a single vehicle or trailer. Each session can take up to 90 minutes, which includes production of official ‘weigh’ slips, a printed report, and a discussion with the owner about possible solutions to any overweight issues.

Similar portable weigh station services are also available out of Brisbane and Perth.

Note: The vehicles and caravan shown being weighed are for illustrative purposes only.

Guide to weight acronyms (supplied by Weigh Station).

Tare weight (Tare)

Tare weight can be found on the caravan’s vehicle compliance plate. This is the total dry weight of the caravan as it leaves the factory including empty water tanks and gas bottles. This may or may not include aftermarket items or accessories fitted after manufacture, which may affect the Tare weight (check with the dealer or manufacturer as to whether this is the case).

Gross Trailer Mass (GTM)

The GTM is the maximum allowable weight the fully loaded caravan imposes on the ground through its axle or axles but does not include the towball mass. This rating may not be exceeded.

Aggregrate Trailer Mass (ATM)

The ATM is the total weight of the fully loaded caravan, unhitched from the tow vehicle. The ATM includes the total weight of the axle or axles plus the weight imposed on the tow ball. The ATM must not exceed the maximum towing capacity of the tow vehicle. This rating may not be exceeded.

Towball mass (TBM)

Towball mass measures the weight the caravan imposes on the tow vehicle. The maximum towball weight for the tow vehicle can generally be found on the compliance plate on the towbar. This rating may not be exceeded.

Gross Vehicle Mass (GVM)

Gross Vehicle Mass is the total weight of the fully loaded tow vehicle. It includes fuel load, passengers, cargo, aftermarket accessories, and includes the towball mass of the caravan when hitched. This rating may not be exceeded.

Gross Combination Mass (GCM)

The Gross Combination Mass is the total weight of the entire rig, encompassing the fully loaded caravan and fully loaded tow vehicle. The maximum allowable GCM is recorded in the vehicle owners manual or on the vehicle compliance plate. This rating may not be exceeded.

Braked Towing Capacity (BTC)

Braked Towing Capacity, also known as braked towing rating, is the maximum weight that your vehicle can legally tow. Vehicle manufacturers equate towing capacity to the Aggregate Trailer Mass (ATM). This rating may not be exceeded.