What are the rules for towing header trailers?

31 July 2020

Combines over 3m width are prohibited from towing trailers with more than 2 wheels. There is a general prohibition under the Road Vehicles (Authorisation of Special Types) (General) Order, 2003 on all agricultural vehicles over 3 m width towing a trailer with more than 2 wheels. This prohibition does not apply to vehicles registered with DVLA as agricultural tractors.

With harvest fast approaching it's useful to have a reminder on the rules on towing header trailers behind combine harvesters.

If a two wheeled header trailer is towed behind a combine there are braking requirements linked to the weight of the trailer as follows:

  • Two wheeled header trailers with a max unladen weight of up to 510kg - no braking requirements
  • Two wheeled trailers over 750kg max laden weigh up to 3.5t max laden weight – overrun brakes are required
  • Two wheeled trailer over 3.5t max laden weight up to a max laden weight of 14.23t – requirement that brakes can be operated by the driver from the driving seat of the towing vehicle whilst remaining in control of the towing  vehicle

If a header trailer is towed behind a tractor the following braking requirements apply:

  • 750kg max laden weigh up to 3.5t max laden weight – overrun brakes are required
  • Over 3.5t max laden weight up to a max laden weight of 14.23t – requirement that brakes can be operated by the driver from the driving seat of the towing vehicle whilst remaining in control of the towing vehicle
  • Over 14.23t - requirement that brakes are operated directly from the service brakes of the towing vehicle

More information is available in these NFU Business Guides:

Further harvest and safety advice on NFUonline:


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