This is the first thing to sort out, because it decides which caravans are even an option for you. Get it right and towing feels boring in a good way. Get it wrong and you have a van that is unsafe, uninsured, or illegal to tow.
The weights, in plain words
Tare weight is what the caravan weighs empty, as it left the factory. No water in the tanks, no gas bottles, no bedding, no food.
ATM (Aggregate Trailer Mass) is the most the caravan is allowed to weigh when it is fully loaded and sitting on its own wheels. This is the number to compare against your car, not the tare.
Payload is simply ATM minus tare. That is everything you are allowed to put in: water, gas, awning, tools, clothes, the dog's gear. A full 100 litre fresh water tank alone is 100 kg.
GVM (Gross Vehicle Mass) is the most your tow vehicle is allowed to weigh, loaded, on its own. Passengers, luggage and the weight pressing down on the tow ball all count towards it.
GCM (Gross Combination Mass) is the most the car and the caravan are allowed to weigh together. It is usually less than GVM plus towing capacity added up, which catches a lot of people out.
What your vehicle is allowed to pull
Your vehicle has two towing limits, and they are very different:
- Braked towing capacity: for a trailer with its own brakes. Nearly every caravan we sell has brakes, so this is the number that applies.
- Unbraked towing capacity: usually only 750 kg, which rules out caravans.
You will find both in your owner's manual, and often on a plate or sticker in the door frame. Do not rely on what a dealer or a forum says the model tows. The same model can differ by year, engine and whether it is two wheel drive.
Tow ball weight
Some of the caravan's weight rests straight down on the tow ball. As a rough guide it is around 5 to 10 percent of the loaded van weight, so 100 to 200 kg on a typical van. Two things follow from that:
- It counts against your vehicle's payload and its rear axle limit, so it eats into what you can carry in the car.
- Your vehicle and your tow bar each have their own maximum tow ball weight. Whichever is lower is your limit.
Too little tow ball weight is the common cause of a van that sways at speed. Loading heavy items low down and near the axle, rather than at the back, makes a big difference.
Doing the check
- Find the caravan's ATM on its plate (we list tare and ATM where we have them).
- Find your vehicle's braked towing capacity.
- The ATM must be under that limit, with room to spare.
- Check the tow ball weight against the vehicle and tow bar limits.
- Add it all up against GVM and GCM.
Rules of thumb
- Leave 10 to 15 percent headroom rather than towing at your absolute limit. New Zealand hills, wind and gravel are not kind to a combination that is maxed out.
- Heavier vans are more settled behind a heavier vehicle. A long van behind a light car is the least comfortable combination.
- The towing speed limit in New Zealand is 90 km/h, even where the posted limit is higher.
- Weigh the loaded van and car at a public weighbridge once, early on. It usually costs very little and it takes all the guesswork out.
If you tell us your vehicle and what it is rated to tow, we can tell you straight away which of our caravans are a sensible fit.