Stephen Ward
Caravan & Boats

In the UK, safe towing requires adhering to your vehicle's Gross Train Weight (GTW) and Maximum Allowable Mass (MAM), which are found on the VIN plate or vehicle handbook. GTW is the maximum combined weight of your loaded car and trailer, while MAM is the maximum loaded weight of a single vehicle or trailer.

 

To find your car's maximum towing capacity, subtract its MAM from its GTW. Additionally, the 85% rule, which recommends the fully loaded trailer not exceed 85% of the car's kerbweight, is a widely recommended safety guideline for novice drivers.

 

Key Terms and Weights Explained

 

•Gross Vehicle Weight (GVW): The maximum loaded weight of your vehicle (MAM of the vehicle).

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•Gross Train Weight (GTW): The maximum combined weight of the fully-loaded car and the fully-loaded trailer.

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•Maximum Allowable Mass (MAM): The manufacturer-defined maximum allowed weight for a vehicle or trailer when fully loaded.

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•Kerbweight: The empty weight of your car, excluding passengers and payload, plus a standard 75kg for the driver.

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•Mass In Running Order (MiRO/MRO): The unladen weight of a caravan when it leaves the factory, including essentials like gas and water.

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•Maximum Technically Permissible Laden Mass (MTPLM): The maximum total weight a caravan can safely be when loaded, as specified by the manufacturer.

 

Where to Find These Weights

 

•VIN Plate: Located on the vehicle, often under the bonnet or inside the driver's door.

•Vehicle Handbook/Owner's Manual: Provides detailed specifications, including towing limits and weights. •V5C Logbook: Your vehicle's registration document also contains weight information.

 

How to Calculate Your Towing Limit

 

1. Locate the VIN plate on your vehicle.

2 . Identify the Gross Train Weight (GTW) and the Gross Vehicle Weight (GVW).

3. Calculate the maximum weight your car can tow by subtracting the GVW from the GTW (GTW - GVW = Max. Towing Capacity).

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The 85% Rule

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•For safety, particularly for novice drivers, it is recommended that the fully laden weight of the caravan or trailer should not exceed 85% of the tow car's kerbweight.

•This rule helps ensure the tow car can safely control the trailer and is less likely to become unstable.

 

Important Considerations

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•Do not exceed your car's GTW or the individual MAM of the trailer.

•Ensure the loaded trailer's weight is within the calculated maximum towing capacity of your vehicle.

•Check your driving license to see which towing categories you are legally permitted to drive. •Consider professional training for safe and stable towing.

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NEW RULES TOWING IN EUROPE as of 25th August 2025

Every towed trailer weighing more than 750kg must have a registered document from the DVLA, display a separate trailer number plate, and carry the trailer registration certificate with it while towing.  This applies to caravans, trailer tents, and horseboxes that are or exceed that weight.

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Exceptions to this rule are Ireland, Cyprus, Malta and Spain; however, when travelling through France or Portugal to get to Spain, you will need the registration document.

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https://www.gov.uk/register-trailer-to-take-abroad

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