Towing Weights – What Do They Mean?

caravan towing safety

Towing Weights On Your Vehicle

Before you head out on the road, or make a final decision about the caravan you buy, it’s important to do your homework. One of the most important aspects of carvanning is understanding towing weights.

The first thing you’ll need to do is match your vehicle with an appropriate sized caravan or camper trailer. In order to do this you’ll need to know the maximum weight your vehicle can safely pull. You’ll find details of the towing capacity weights of your vehicle listed in the vehicle manual.

There are a few different weights that can cause confusion for newcomers to towing.

Vehicle Towing Capacity: This is the maximum trailer weight you can tow and is specified as ‘braked’ and ‘unbraked’. Unless you’ll be pulling a trailer under 750kg, the important weight to know is the braked maximum trailer weight. You must not tow anything that exceeds this.

Towball Maximum Load: This is usually about 8-10% of the vehicle’s maximum towing capacity and refers to the maximum downward pressure allowed on the towball.

These two numbers can cause confusion. Just remember that the maximum towing weight is the full weight of your rig and the towball maximum load is smaller and refers to the maximum downward weight allowed on the towball.

caravan towing and electrics

Caravan Weight & Overloading

You now know the maximum weight capacity of your vehicle. What about the weight of your caravan? There are a few different weights you may come across: ATM, GTM and Tare Mass. It’s helpful to know the difference between each one.

Aggregate Trailer Mass (ATM): This is the total weight of your caravan with payload. It includes everything packed into your caravan or trailer and any after market additions, such as an air conditioner and filled water tanks.

Gross Trailer Mass (GTM): This is the total weight the caravan can support on its axles. It includes the payload, but does not include the maximum downward weight on the coupling. The GTM is always less than ATM. This is because some of the weight is taken by the tow vehicle when the caravan is coupled to it.

Tare Mass: This is the weight of your caravan at manufacture. This will not include anything added after the caravan left the factory. If you are buying a second hand caravan, this is important because if it has had modifications that have added to the weight, the caravan may actually weigh more than you think.

Weighing Your Rig

To find out the weight of your caravan, you will need to take it to a weighbridge and weigh it fully loaded. The towball mass will be between 8 – 10% of the total weight of your rig (or ATM minus GTM).

If you are buying a second hand caravan it’s a good idea to have it weighed before finalising a purchase, in case it has had any modifications made post manufacture.

safe driving towing weight

Safety Margins Of Error

It’s helpful to know that all towing guidelines allow for a lot of leeway. While there is a generous margin of error in these maximum towing weights it is important to treat them seriously and adhere to them when you are:

  • matching a towing vehicle to a caravan or trailer;
  • considering any major modifications to your caravan or trailer;
  • loading your caravan or trailer for a trip.

The weight of your loaded  caravan should not exceed:

  • the maximum weight recommended by the caravan manufacturer
  • the towing limits recommended by the car’s manufacturer, or
  • the weight rating of the towbar.

Towing Your Caravan Safely

Towing a caravan or trailer safely relies upon not exceeding maximum towing weights. Many accidents are caused by overloading, which can result in tyre blow outs, sway and losing control of your caravan.

When you are thinking about any modifications to your caravan you need to take into consideration the increased weight that these will impose on your rig. If you talk to an experienced caravan service centre, they can help you to determine the right solution and make sure you do not add too much to your caravan.

To find out more about caravan modifications or to book a caravan service, contact Emu Caravan Repairs. Our caravan service centre is  located in the eastern suburbs of Melbourne. We service customers across Melbourne’s eastern suburbs, Yarra Ranges, Yarra Valley and Gippsland