09/02/2026
If you’re looking for a new caravan or upgrading, this article is vital reading.
THE HIDDEN WEIGHTS THAT MANY FOOLISHLY IGNORE WHEN BUYING A NEW TOW VEHICLE OR CARAVAN.
After spending some time at caravan expos over the last 14 months we have heard many concerning stories from buyers who do not fully understand the legally binding weights when towing.
Many buyers and salespeople purely look at Braked Towing Capacity (BTC) as a reference on whether a certain vehicle can tow a certain trailer or caravan.
This is extremely foolish and can end up costing the buyer thousands of dollars to rectify the impulsive and under researched purchase.
LET ME EXPLAIN.
Basically, there are six main weights to consider in an initial hunt for that right vehicle or caravan. Many other weights and measurers also need to be considered before the final decision is made.
These main weights include but are NOT limited to the following in summary: -
TOW VEHICLE WEIGHTS – referring to Light Vehicles being those under 4,500 GVM and driven on a ‘car’ licence.
GVM – Gross Vehicle Mass being the maximum legal weight that vehicle can weigh when fully loaded. As set by the manufacture.
GCM – Gross Combination Mass being the maximum legal weight that vehicle and any attached trailer can weigh when in combination. (Hooked up) As set by the manufacturer.
BTC – Braked Towing Capacity being the maximum legal weight that the vehicle can tow. This is based on the total actual weight of the entire trailer and load including tow ball weight plus axle weights. It is the same whether the trailer is a Pig Trailer like a caravan, a 5th Wheeler or Goose Neck type trailer. The BTC refers to ALL trailer configurations for a light vehicle. Heavy vehicle classes have different rules. The BTC cannot be legally exceeded.
TRAILER / CARAVAN WEIGHTS
TARE Weight – This is the weight as specified by the manufacturer that the trailer weighed when manufactured and usually displayed on the trailer plate. It is not necessarily the weight of the caravan sold by the dealer. It may include everything, or it may not include bedding, awning, batteries and solar, etc. It is for that reason I recommend not worrying about the Tare weight of a caravan as you will never tow it at that weight and many dealers add extra solar, batteries, water and gas storage boxes and other items making the Tare weight irrelevant in doing your calculations.
Some are very accurate but others out by hundreds of kilos. When I ask what weight the caravan is, many simply quote the tare weight, when the van will never be towed on a trip at the tare weight. If you base your calculations on the Tare weight and it is wrong all other answers will be wrong. Get you new caravan weighed before you dive out of the dealership so that you have an accurate bare stating weight.
GTM – Gross Trailer Mass is the maximum weight that the caravan or trailer can have on the axles / wheels when travelling, as set by the manufacturer. Different suspension systems can alter the balance between axles, therefore, just because you are under the maximum allowed GTM does not mean that your individual axles are within max legal ratings. One axle can be carrying more load than another and be overloaded when the second axle is only carrying a smaller percentage of the full trailer weight.
ATM – Aggerate Trailer Mass is the maximum legal weight that the entire trailer can weight, including the weight on all wheels plus the tow ball weight. As set by the manufacturer.
MY CONCERNS.
Many just look at the BTC – Braked Towing Capacity of a tow vehicle to decide if it can tow a certain caravan. It really depends on what you want that tow vehicle to do for your individual needs. How much load verses how much towing.
Firstly, for light vehicles towing a typical caravan or trailer, (Pig trailer via an overhung hitch like all most all caravans being towed in Australia) the fully loaded tow vehicle should always be heavier than the fully loaded trailer it tows. This is for safe towing, and you will certainly notice the difference in any emergency situation or when the caravan sways. You do not want a heavy van pushing a light tow vehicle around despite what the BTC says it can do. There is a BIG difference between what is legal and what is safe.
Let’s look at a couple of examples.
NEW FORD SUPER DUTY.
A great stronger vehicle than the standard Ford Ranger. It has 4,500 kg braked towing capacity so many are looking at it as a potential tow vehicle for one of the new generations of heavier all electric caravans now available. It has a GVM of 4,500 kgs meaning you can load it with extra ‘stuff’ so the car and ‘stuff’, driver and passenger and all accessories can weigh a maximum of 4,500 kgs.
HOWEVER, the Super Duty has 4.5t towing capacity but only a GCM (See above description) of 8,000 kg.) This means that when fully loaded to maximum GVM at 4,500 kgs you only have left 3,500 kgs available for towing the caravan. 8,000 GCM less 4,500 GVM leaves 3,500 for the caravan weight. (Tow ball weight is included in GVM) This also reverses when towing a 4,500 kg caravan, you only have 3,500 kgs left for the super duty, load, accessories and people on board.
So, NO you cannot load it to 4,500 kg GVM and expect to still tow that 4,500 kg caravan you just bought because the salesperson said you can.
MY FORD RANGER
It has a GVM of 3,500 kgs due to a legal GVM upgrade from the original 3,200 kgs GVM. However, there is no GCM upgrade available for that particular model, so the original 6,000 kgs GCM still stands as the maximum legal weight of Ranger and caravan being towed. It has 3,500 kgs braked towing capacity. So, can it legally tow a 3,500 kgs caravan like the salesperson said I could?
Load to full new GVM of 3,500 kgs and take that from the original GCM of 6,000 and I only have 2,500 kgs left for the Ranger to weigh legally within the GCM. The Ranger weighs 2,300 kgs with a full tank of fuel leaving only 200 kgs for my bull bar and canopy on it, stuff in the tray like second battery and fridge and Jenny and I in the front seats I would be drastically overloaded if I towed a 3,500 kgs van with that vehicle.
There are many vehicles that have a GCM allowance so that the vehicle can be loaded to maximum GVM and still tow the rated Braked Towing Capacity. My Iveco Daily is one such vehicle.
Many other weights also need to be considered including the physics of towing. Did you know that 300 kgs on the tow ball on a typical light vehicle towing a caravan can add approximately 450 kgs top the rear axle. The weight on the overhung tow hitch lifts weight off the front axle transferring it to the rear axle. Lighter front axle but much heavier rear axle, in some cases overloading it.
I was told by a car salesperson that the Kerb weight of a Ranger includes driver and passengers. It does not. It is basically the Tare weight with a full tank of fuel.
My message is, please do some research so that you understand FACT FROM FICTION in caravan and car sales world. While the majority of salespeople are great and know their products there is no compulsory training required for car or vehicle salespeople to understand vehicle weights. I believe this is wrong and the Govt need to help protect the consumers from misinformation.
Until they do, it is up to the consumer to do their own education and research to protect themselves.
This and much more information on selecting the right tow vehicle and matching it to the right caravan is available in our popular book,
SAFE CARAVAN TOWING – THE MANUAL/
Available from the Truck Friendly web site or at the Truck Friendly stand at the MORTON BAY EXPO, 13th to the 15th of February, at the Redcliffe QLD Showgrounds.
Website link.
https://www.truckfriendly.com.au/safe-caravan-towing-the-manual/
RACQ will also be at the Morton Bay Expo presenting sessions on safe caravan towing, 10 am, 12 noon and 2pm daily. They are highly recommended.
Stay safe.
Ken Wilson
Truck Friendly caravan road safety program
[email protected]
