Do you know how to check your towing capacity?

Vin plate

We often get asked what the towing capacity of a tow bar is, but it is your car that determines what you can tow safely and legally.

The exact towing capacity figure that should be used for your vehicle is that which is stamped on the Vehicle Identification Number Plate (VIN Plate). The VIN plate can usually be found under the bonnet or on a door pillar and details of the location will be in the owner’s handbook.

The VIN plate will display either 3 or 4 sets of weights.

  • – 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 maximum weight includes passengers, other loads, and fuel.

To calculate the recommended maximum towing capacity for your vehicle is the gross vehicle weight (A) subtracted from gross train weight (B).
On the above example 4200kg – 2505kg = 1695Kg

In addition for safe towing it is recommended by many towing experts that a novice should keep the fully laden weight of the caravan no heavier than 85% of the kerbweight of the tow car. This is known as the 85% rule. Bear in mind that it is a guide and not legally enforceable.

To calculate this, you need to know two key figures: the kerbweight of the car and the maximum mass of the caravan (called ‘maximum technically permissible laden mass’, or MTPLM).

If the mass of the caravan is 85% or less of the car’s kerbweight, the car will tow it with ease.

If it’s between 85% and 100%, be careful – only experienced caravanners should use that car to tow such a heavy van.

Did you know?
Certain performance, hybrid and city-car models or similar variants of standard models are not homologated to tow, including some cars with panoramic sunroofs, 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.

13 thoughts on “Do you know how to check your towing capacity?”

  1. Hi, my cars maximum weight is 2450 but the maximum combined tow weight is 5240, my partner can only to a maximum of 3500, would she be legally allowed to tow upto 3500 weight with this car

    1. No, if the gross vehicle weight is 2450, and your gross train weight is 5240,
      5240 – 2450 = 2790
      So 2790 is the maximum tow weight for the vehicle, but remember that includes you and any luggage etc.

        1. Yes, for safe towing it is recommended by many towing experts that a novice should keep the fully laden weight of the caravan no heavier than 85% of the kerbweight of the tow car. This is known as the 85% rule. Bear in mind that it is a guide and not legally enforceable.

    1. Hi Tony. You need to check your towing capacity of the car using the method in this article, so many factors can effect this so using the vin plate is the only sure way to know what you are legally allowed to tow. If the figure of 1800kg refers to the kerb weight of your vehicle, then you are just over the 85% rule at 86.6%.

  2. Hi , I have a 19 plate Kia Niro Hybrid.
    Most car reviews and internet site state that them,y vehicle can tow, but the manual only refers to towing of European vehicles despite the VIN Plate displaying the 4 weights. Kia UK customer service state that my vehicle is not suitable for towing , but the location dealership say that if the VIN Plate has the the required info then I could tow. Not sure who is right as I wouldn’t like to void my warranty or get into trouble with the law.
    Can you advise please?
    Thanks , Gerry

    1. Hi Gerry. If your vin plate displays all four weights your car is legally allowed to tow – up to the towing capacity as worked out using the method above. It is illegal to tow over this weight. Handbooks can often be misleading as they try to cover everything and are not specific to the actual vehicle (I’ve brought tears to a poor mans eyes when I had tell him that his recent purchase of a car to take the family caravanning was not homologated for towing due to the optional extras on the car, despite the manual and the dealership saying it could, doh!). I’ve checked and a tow bar is available for the Kia Niro Hybrid. Hope this helps.

    2. Hi Gerry

      We have the same question – where did you find the VIN plate. The manual only refers to the location of VIN numbers – no weights, just the VIN number.
      Thanks
      Patrick

  3. Hi I have a swift kontiki 669 and I’m trying to ascertain the permitted tow weight of the vehicle, it has a tag axle and the trailer il be using is twin wheeled,

    1. Hi Kevin, you should still have a weight / von on your motorhome. Same principle as in article, minus the weight of the vehicle from the gross train weight and it will give you a maximum towing capacity.

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