When towing a caravan for the first time, or upgrading either the caravan or towing vehicle, it is essential to understand the mandatory requirements for safe and legal towing. This will ensure your vehicle insurance remains valid for the trip, you meet legal requirements to avoid potential fines, and the risk of damage to the towing vehicle and occupants is minimised.
Taking the time to understand caravan towing weights is well worth the effort. In situations where you need to stop suddenly or swerve to avoid a collision, knowing your towing limits ensures you have the best chance of maintaining control of the vehicle and safely navigating the situation.
Check the towing specifications for your towing vehicle
A vehicle’s towing capacity is the maximum weight it can legally tow, and it’s determined by the vehicle manufacturer. The numbers you need to know will be found in the vehicle owner's manual. It may also be printed on a plate or stamped inside the car door frame. If you don’t have the owner’s manual, make sure you use the exact make, model and vehicle variation when searching online.
More info: Towing your first caravan: the things you should know
Towing capacity numbers can include the towing capacity, kerb weight, tare weight, maximum tow ball weight, gross combination mass, gross vehicle mass (this will all be explained below), all of which can be used to calculate the maximum payload.
Check the caravan towing weights
It’s mandatory for caravans to have a compliance plate which detail:
- tare weight
- tow ball weight
- aggregate trailer mass
- gross trailer mass
Look inside the front boot or tunnel boot, or check with the manufacturer if you can’t easily find it. Once you have these figures, note that the aggregate trailer mass of the caravan will need to be less than the towing vehicle’s maximum capacity — we’ll cover this below.
Keep learning: Everything you need to know before towing
Caravan weights explained
Now that you know where to find the information about your caravan and towing vehicle, let’s clear up these numbers and identify what calculations you need to make before starting your next adventure.
Tare weight
The tare weight is the weight of the empty vehicle, with fluids like coolant and oil and just 10L of fuel. Tare weight excludes accessories such as roof racks and luggage.
Kerb weight
The kerb weight is the weight of the towing vehicle with a full tank of fuel, before accessories, luggage or passengers are factored in.
Gross vehicle mass (GVM)
The GVM is the maximum weight of the vehicle when fully loaded according to the manufacturer’s specifications. It includes accessories, luggage and passengers, on top of the kerb weight. If you are towing a caravan, the GVM also includes the tow ball weight.
Tow ball weight (TBW)
The downward force of the caravan on the tow ball. Tow ball weight should generally be around 8-12% of the gross trailer mass (GTM) to ensure safe and stable towing.
Tow ball mass can be measured at a weighbridge by unhitching the caravan and resting just the trailer draw bar (using the jockey wheel) on the scale.
Aggregate trailer mass (ATM)
ATM is the maximum total weight of the fully loaded caravan before it is hitched to the towing vehicle. This includes accessories and the luxuries or appliances that upgrade your carvanning experience.
Gross combination mass (GCM)
The GCM combines the mass of the maximum loaded caravan and towing vehicle. GCM is the weight you would record if you drove a fully loaded caravan and vehicle onto a weigh bridge.
Gross trailer mass (GTM)
The weight of the fully loaded caravan measured at the axles, when connected to the towing vehicle.
Payload
The payload is the weight that you can add to the caravan when packing for the trip, and it includes modifications and accessories. The payload is the difference between the tare weight of the caravan and it’s aggregate trailer mass (ATM) and tow ball weight.
Getting started: Towing 101: What you need to know when towing
How do you ensure tow vehicle towing capacity matches caravan weight?
Now that you know how to find all of this information, it’s time to work out if your towing vehicle has the right capacity to tow the caravan.
Step 1: Check the vehicle’s maximum braked towing capacity
Most caravans have electric brakes that can be controlled by an electric brake controller, like the Tow Pro. Towing a braked caravan means safer towing and a higher towing capacity. Check the maximum braked towing capacity for your vehicle, using the VIN number to search for the owner’s manual.
Step 2: Connect an electric brake controller
Using an electric brake controller allows the towing vehicle to haul a heavier load than it could with an unbraked trailer.
The Tow-Pro electric brake controller by REDARC provides smooth braking for both 12V and 24V vehicles. It’s built for towing a caravan or a camper trailer across tarmac or off-road.
When a caravan is unbraked, it relies on the towing vehicle to brake and slow the weight of both the caravan and the vehicle, so braking is slower, and in high winds or uneven roads the caravan is more likely to sway and affect the vehicle. Most caravans come with electric brakes, which require an electric brake controller to work.
When the driver brakes the vehicle, the brakes on the caravan will activate, ensuring the caravan slows smoothly. An electric brake controller that allows both proportional and driver-controlled braking means that you gain control over the caravan in tricky or emergency situations.
Applying the caravan’s electric brakes from the driver’s seat can be the difference between swaying off the road or safely controlling the caravan’s movement and continuing on your journey without incident.
Step 3: Determine ATM, GCM and payload
Using the definitions above, calculate the total weight of the loaded but unhitched caravan (ATM) and combined weight of the loaded caravan and vehicle. This can be done at a weigh bridge.
The ATM must not exceed the total maximum towing capacity of the towing vehicle. Keep in mind that the load in the vehicle effects the total payload of the vehicle and reduces towing capacity — this weight must be factored in within the GCM limit.
You should also check the capacity of the towbar itself — if the vehicle and tow bar state different capacities, work with the lower figure. Ideally, you want to leave a 10-20% buffer between the caravan weight and the maximum towing capacity of the vehicle to improve safety and performance.
Prepare for your next caravanning adventure with REDARC
Choosing a braked caravan means you can take more gear with you for camping comfort. As you prepare for your caravanning adventure, you’ll need to consider everything that makes the journey possible.
REDARC’s Tow-Pro can help ensure a smooth, safe and enjoyable driving experience, whether you are a seasoned road-tripper or towing for the first time. Take the Tow-Pro off-road or be confident on the great open roads of Australia — for seamless braking and safe and efficient stopping, you can’t beat this award-winning electric brake controller. Pack your bags, hitch up the caravan and hit the road with peace of mind that you’re prepared for every challenge the road will bring!
Frequently asked questions
What is the weight rule for a caravan?
When towing a caravan, it's generally recommended to aim for 10-20% of the gross combination mass (GCM) for optimal safety and performance. This helps ensure that your tow vehicle operates smoothly while maintaining better control on the road. Be mindful to keep the total weight, including passengers and luggage, under the maximum GCM to ensure a safe and efficient towing experience.
Does a caravan tare weight include full water tanks?
The caravan tare weight is the weight when the caravan is completely empty. This means that gas bottles and water tanks are empty. Accessories and options that came with the caravan are included in the tare weight, for example, the battery and power systems.
Can I tow a caravan with a higher ATM?
You can tow a caravan that has a higher ATM than the total vehicle towing capacity, provided that you do not load the caravan to the maximum. The total (actual) weight of the fully loaded trailer must be within the towing limits of the vehicle to be compliant and safe.