Knowing all of the various towing weight terms and meanings can be a minefield when you’re first starting out. However, it’s one of the most important aspects of caravanning that you can educate yourself on.
Keeping within your legal weight limits will keep your set-up compliant with the road authorities, which saves you from being fined or grounded. But, more importantly, it will ensure that you are as safe on the road as you can be.
Here, we’re going to tackle caravan ATM weight and what that includes for your set-up.
Caravan ATM is only one of the caravan weight terms that you’ll need to know. Make sure you educate yourself on all of the towing weights required for setting up a caravan.
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What is Caravan ATM Weight?
Caravan ATM (Aggregate Trailer Mass) is the maximum weight that the caravan is allowed to be when fully loaded and unhitched from the tow vehicle.
This figure is set by the manufacturer and cannot be changed. It is the legal weight that the manufacturer’s engineers have calculated based on what the suspension and chassis are safely capable of carrying.
As stated by the Australian Government in the Vehicle Standards Bulletin 1 (VSB1):
12.5 Aggregate Trailer Mass (ATM)
ATM is the total mass of the trailer when carrying the maximum load recommended by the manufacturer. This includes mass imposed onto the towing vehicle when the combination vehicle is resting on a horizontal supporting plane.
Where to Find Your ATM
It is a legal requirement that ATM weight is stamped onto every caravan’s compliance VIN plate.
Caravan VIN plates are generally found just inside the entry door (on the side of a cabinet), inside the front tunnel boot or on the drawbar.
What Does Caravan ATM Weight Include?
As the caravan ATM weight is the absolute maximum weight that the caravan is ever allowed to be, it literally includes everything.
This is the weight of the empty caravan + every accessory, modification & item that is added to it.
Caravan ATM Weight Includes:
- Full water tanks
- Full waste tanks (black water, grey water & toilet cassette)
- Full hot water system
- Full gas bottles
- Food & drinks
- Cooking gear
- Toys, bikes, scooters, games, books etc.
- Personal luggage (electronics, toiletries etc.)
- Camping furniture (chairs & tables)
- Jerry cans & holders
- Tools, toolboxes & maintenance gear
- Hoses & leads
- Levellers & chocks
- Annex walls/ privacy screens
- Outdoor matting
- Upgrades (solar system, additional water tanks etc.)
… and anything else that is added to the caravan either permanently or temporarily
How to Find the Weight of Your Caravan
To ensure that your caravan is under its ATM, you will need to weigh it at a Public Weighbridge. You can usually find a weighbridge at your local council waste and recycling centre.
Below are the steps on how to weigh your caravan to make sure that it’s under the specified ATM.
How to Weigh Your Caravan:
- Ensure the caravan is fully loaded for travel
- Drive the caravan onto the weighbridge and unhitch it from the car
- Drive the car off the weighbridge, leaving only the caravan on the scales
- Record the weight
- This needs to be lower than the manufacturer stated ATM
To find out all of the weights for your tow vehicle and caravan, check out the article below.
What to Do if You’re Over Your ATM
If you weigh your caravan and find that it’s heavier than your ATM, you will need to remove weight from the caravan until you can get it under that ATM figure.
Remember, ATM is the maximum weight that the unhitched caravan is allowed to be at any given time.
Now it’s time to get serious about what you actually need in your caravan versus what you think you need.
The quickest way to reduce the weight of the caravan is to empty the water tanks. Think about it, with three full 80L tanks of water, that’s 240kg straight away. Quite often, it’s the full water tanks that will push people’s set-ups over the limit.
Unfortunately, that means you’ll need to fill up the tanks either at camp (if they have a potable water tap), or as close to camp as you can get.
Don’t feel disheartened if you don’t have the weight allowance to travel with full water tanks, it’s more common than you may think.
To read more on the pros and cons of travelling with full water tanks, check out the article below.
If you want to be able to travel with full water tanks, then you’ll have to look at how else you can remove weight from your caravan.
Go through all of your luggage, camping gear, food, drinks and personal items to cull as much as you possibly can.
❓ Have you got a bike rack or toolbox that never gets used and can be removed?
❓ What about extra camping furniture or cast iron cookware that you really don’t need?
❓ Look at reducing the amount of food, clothing & linen onboard
❓ Think about unnecessary electronics, gadgets and appliances
This is the time to be as ruthless as you can because not only is having an overweight caravan illegal, it’s also dangerous and voids your insurance. It’s just not worth the trade-off for having a few extra items onboard that you probably don’t need.
Things to remove from the caravan to reduce its weight:
- Empty the water tanks
- Reduce the amount of luggage
- Remove unnecessary accessories
Use the Caravan Packing List below to keep track of which items you have packed into your caravan.
To organise your payload, there is a ‘weights’ column in the checklist, plus we also have a Payload Calculator available.
Caravan Packing List
Never forget a thing with the ULTIMATE Caravan Packing List!
- Pre-filled with 600+ items
- 17 categories
- ‘Weight’ column (to organise payload)
- PRINTABLE – fully customisable
- DIGITAL – completely interactive
- Download once, use it over-and-over
Caravan ATM Weight FAQs
ATM is the maximum allowable weight of the fully loaded caravan at any given time, while GVM is the fully loaded weight of the vehicle (with the maximum GVM weight being specified by the manufacturer).
Yes, caravan ATM does include the ball weight, as it’s the weight of a fully loaded caravan that is unhitched from the tow vehicle.
A caravan with an ATM of 3,500 kg means that the weight of the caravan when it’s fully loaded and unhitched from the tow vehicle, must not exceed 3,500 kg.
Yes, caravan ATM includes water and every other item that is in or on the caravan, making up the total of its fully loaded weight.
While ATM is the maximum allowable weight of the fully loaded caravan, GCM is the combined weight of both the fully loaded tow vehicle + caravan together.
Tare weight is the empty weight of a car or trailer, while ATM is the fully loaded weight of just the trailer (such as a caravan).
A caravan’s ATM weight is set by the manufacturer, but to find if you’re under your ATM you need to weigh your fully loaded caravan (unhitched from the vehicle) at a weighbridge.