Confused by Towing Weights? A Police Sergeant’s Guide to Common Errors

WORDS RACHAEL DOHERTY

Understanding towing weight compliance is a major hurdle for many caravanners, often leading to confusion around GVM and GCM limits. For Queensland Police Sergeant Brett Vinson, this goes beyond professional concern; a keen caravanner, towing safety is close to his heart.

“My best caravan experience was travelling the east coast in 2020 after the lockdown we would try different bakeries, go to waterfalls and day trips on the reef and Magnetic Island.”

Contrasting to fond family memories, road safety statistics linking tow weight breaches and uneven loading to driver accountability in a collision weigh on his mind.

Understanding Caravan and Tow Weight Compliance: A Common Challenge

Sergeant Vinson finds the resulting interest encouraging but out on the roads, some travellers are slow to change.

“I think people want to comply with towing limits but they aren’t sure.”

The sergeant fielded countless inquiries at the Brisbane Caravan Supershow.

“Those who already own a tow vehicle and are looking at caravans to buy or order, they look at the weights of the caravan and sometimes realise their vehicle may not be suitable.

“They have to go back to the drawing board.”

It can be a nerve-wracking time for buyers but an important one for road safety. For a deeper dive, many resources are available for understanding tow weights.

The Most Common Towing Breach: Exceeding Your GVM

“The main breaches so far are caravanners being over in the GVM [limit] of their vehicle,” says Sergeant Vinson, the GVM limit being the most your tow vehicle can weigh including travellers.

He says some travellers don’t realise they need to add the Tow Ball weight to the vehicle’s weight to ensure they’re within the GVM limit.

“Most times, if you are over the GVM [limit] you will be over your rear axle weight.”

Sergeant Vinson once intercepted a couple who were 100 kilos over their Tow Ball Weight limit.

“They had a near-new towing vehicle and a new caravan. They had a Tow Ball Weight of 450kg. The scary part was the front of the caravan wasn’t even loaded full.

“They had to move their load around and reduce the Tow Ball Weight before they could move on.”

Decoding Tow Ball Weight and Vehicle Limits

“I think the Tow Ball weight and what it goes towards causes the biggest confusion,” says Sergeant Vinson. This is a common sentiment, as the physics behind tow ball mass and leverage can be complex.

“For example, the Tow Ball weight is included [when measuring for] the GVM of the vehicle. Also, the Tow Ball Weight is included in [when measuring for] the ATM of the caravan.”

But, when you’re measuring the caravan and the tow vehicle to see if you’re within the Gross Combined Mass (GCM) limit, you only measure the Tow Ball Weight once. Not all vehicles have a GCM limit but those used for towing large caravans usually do.

The GCM Trap: How Accessories Impact Your Towing Capacity

It’s a vital limit that dictates the very most your entire rig can weigh, with all passengers on board. Sergeant Vinson is also seeing GCM limit breaches, where vehicles (often dual-cab types) are carrying too much weight to safely tow their load.

Indeed, 4WDing accessories, camping gear in your tow vehicle’s cabin or even your family can calve into your vehicle’s available towing capacity, depending on your vehicle’s GCM.

“I see caravanners buying dual cab utes who may not understand that their GCM [limit] is around 6000kg, and they also want to tow a large 3 to 3.5T caravan,” says Sergeant Vinson.

“Vehicle manufacturers state the vehicle Braked Towing Capacity is 3500kg; however, if the caravanner is at their maximum GVM, then they can’t tow 3500kg.”

Your Action Plan: Get Weighed and Know Your Limits

To get a proper grip on your rig’s limits, Sergeant Vinson suggests loading your car and caravan as if you’re leaving, with full water and all your gear plus a bit extra in the van.

“Then, get your set-up weighed with everyone who will be travelling in the car. This will give you a worst-case scenario.”

Sergeant Vinson says to then remove gear and adjust the weight so you know what you can take: “If you get all your weights compliant whilst fully loaded, you then have a benchmark to work with and if that includes all the extra gear you packed, then great.” There are many practical tips on how to reduce caravan weight if you find you are over your limits.

Having your towing set-up professional weighed can clarify these important weights and limits.

“Please, know your limits for the car and the caravan.”