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Mastering the Art of Towing: Understanding Vehicle and Trailer Weights

ByNyree Johnson

When it comes to towing, it’s essential to know what weight you have to work with and understand how best to use it. There are quite a few components to vehicle weights.     

Each vehicle has the weight ratings set by the manufacturer. This covers Gross Vehicle Mass (GVM), TARE weight, Payload weight, Braked Towing Capacity and Gross Combined Mass (GCM). 

  • Gross Vehicle Mass (GVM) is the gross weight of the vehicle. 
  • TARE weight is the weight of an unladen vehicle with approximately 10 litres of fuel and no driver. 
  • Payload weight is the difference between TARE weight and GVM, and is essentially the amount of allowable weight you can put in your vehicle to take you up to the GVM.   
  • Braked Towing Capacity is the allowed amount of weight you can tow, as determined by the manufacturer. 
  • Gross Combined Mass (GCM) is the Gross Vehicle Mass (GVM) plus Braked Towing Capacity. 

It is essential to know your weights to ensure safety and prevent an incident or accident. If you exceed your manufacturer’s specifications and have an incident where the weights could be a contributing factor, your insurance company may not cover your property or pay your claim. 

To share an example of how this plays out, let’s review a stock standard 2020 Toyota Landcruiser Wagon GXL VDJ200 

  • GVM: 3350kg 
  • TARE: 2630kg 
  • Payload: 720kg 
  • Braked Towing Capacity: 3500kg 
  • GCM: 6850kg 

Imagine that we load the Landcruiser with three children and two adults at a total weight of 280kgs. Then, fill the diesel tank with 138 litres which is 120kg. Next, we load the luggage into the back of the car for a weeklong holiday at an approximate weight of 100kg. The vehicle now uses 500kgs of the allowed Payload weight of 720kg, leaving 220kg available. 

Caravans and camper trailers have their own set of weights, of course, and in addition to TARE weight and Payload weight, there is the Aggregate Trailer Mass (ATM) and the Ball weight to consider. 

The Aggregate Trailer Mass (ATM) of a caravan or camper trailer you purchase cannot exceed the Braked Towing Capacity of your vehicle. Landcruiser example: Braked Towing Capacity is 3500kg. 

Most Ball weights are calculated at a maximum of 10% of the Aggregate Trailer Mass (ATM) and must be factored into your vehicle’s Payload weight. 

If we consider a 17-foot caravan with an Aggregate Trailer Mass of 3500kg, we meet the requirements for the Braked Towing Capacity. The Ball weight consideration would be 350kg and needs to be factored into the Payload weight. 

Using the example of the Landcruiser, we only have 220kg Payload weight available for the Ball weight requirement of 350kg.    

If we use the Landcruiser example and the 17-foot caravan, we add the TARE + Payload + Ball weight, and we exceed the manufacturer’s specifications. 

  • TARE (2630kg) + Payload (500kg) + Ball weight (350kg) = 3480kg 
  • The GVM allowance for the Landcruiser is 3350kg, meaning we are 130kg overweight.   

Knowing your weights allows you to move items around from the vehicle to the caravan or trailer. Keep in mind that moving objects around in the item you’re towing will also affect your Ball weight. 

To share an example of a caravan and how it works with the Landcruiser mentioned, we’ll look at a 2022 MDC XR17HRTDB 15 YR Edition 

  • Aggregate Trailer Mass (ATM) 3500kg 
  • TARE weight 2760kg 
  • Payload weight 740kg (ATM – TARE = Payload) 

This caravan has 2 x 80 litre freshwater tanks (160kg) and 1 x 80 litre greywater tank (0kg at the trip’s start). It can also carry 2 x 9kg LPG gas cylinders (18kg) and 2 x 20 litre jerry cans (40kg). Add food and luggage, and we’re at approximately 220kgs of the 740kg Payload weight allowed for the caravan.   

Considering the original layout of luggage in the tow vehicle is pushing the Gross Vehicle Mass (GVM) overweight, now is when you’d consider moving the 100kg of luggage from the tow vehicle to the caravan. 

The caravan also has a 150 litre built-in fridge with kitchen essentials weighing approximately 25kg. The camp fridge at 80 litres is full of camp cooking and drinking essentials, weighing roughly 60kg. This leaves us at 400kg of the allowed 740kg Payload weight of the caravan. 

On goes the bikes, kayak, BBQ, fishing or camping gear, and soon you are at approximately 550-600kgs of the 740kg Payload weight of the caravan. 

It’s important to know that how the caravan is loaded will also determine the Ball weight, so we still have an opportunity to move that luggage from the tow vehicle to the caravan into a prime position. 

It is easy to see how you can become overweight very quickly. If you like to caravan with all the gear, it may take a few trips over the weighbridge to get your set up in the allowed specification window. This is only one safe example, remembering it is a stock standard Landcruiser with no bulbar, winch, or other weighty accessories fitted. 

If you are unsure what your weights are meant to be, open your vehicle’s user manual, and it will tell you the weights and dimensions. The same applies to the trailer specifications, and you will also find these on the compliance plate or they can be made available from the manufacturer.   

If you’re still not sure, be sure to ask for help from a specialist. This enables your safety, a successful trip, and the safety of all other road goers. 

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