Calculating a Vehicle’s Towing Capacity
Details of the towing capacity for your vehicle that are found in the owner’s handbook, the manufacturer’s website and on other websites should only be taken as a guide.
The actual, exact and only towing capacity figure that should be used for your vehicle is the one that is stamped on the Vehicle Identification Number Plate, VIN Plate.
The VIN Plate
The VIN plate will display either 3 or 4 sets of weights, it is these weights that VOSA or the other vehicle authorities use to determine whether your vehicle is towing or being driven within the law.
- The top figure ‘A’ is the gross vehicle weight, the Maximum Allowable Mass (MAM) of the vehicle including occupants, fuel and payload.
- The second figure ‘B’ is the gross train weight, this is the combined maximum allowable mass of the vehicle and trailer.
- The third and fourth figures ‘C’ and ‘D’ are maximum axle loads front and rear respectively.
The manufacturer’s recommended maximum towing capacity for your vehicle is the gross vehicle weight subtracted from gross train weight. (4200kg – 2505kg = 1695Kg)
This calculation is based on a fully laden vehicle.
Certain performance, hybrid and city-car models or similar variants of standard models are not homologated to tow, this means that the vehicle manufacturer has deemed that the model is unsuitable for use as a tow vehicle. With this type of vehicle, the towing capacity will equate to zero or a gross train weight will not be displayed.