Light trailer safety chains and shackles
When towing a light trailer you must use suitable safety chains. You must make sure they are correctly attached to the towing vehicle.
Trailers are categorised by their aggregated trailer mass (ATM). This is the combined weight of the trailer and its maximum legal load.
A light trailer is one that has an ATM of up to 4,500kg and can also include caravans and boat trailers.
The ATM will be listed on the trailer's Vehicle Identification Plate.
Shackles can be used to connect the safety chain to the towing vehicle.
Trailers with an ATM up to 2,500kg only need one chain rated to the capacity of the trailer.
Trailers with an ATM over 2,500kg and up to 3,500kg ATM must use two chains each rated to at least 3,500kg.
Trailers with an ATM over 3,500kg must use two chains rated to at least 4,500kg.
Read the light trailer requirements bulletin .
When using shackles you must ensure you choose the right one to connect the trailer's safety chain to the towing vehicle.
The table below lists recommended bow or D-shackles to suit light trailers with an aggregated mass up to 3,500kg.
The sizes are based on the diameter of the shackle.
| Trailer ATM|
| Minimum shackle|
Working Load Limit (kg)
|Grade M (or 4) D-Shackle (mm)||Grade S (or 6) D-Shackle (mm)|| Grade S (or 6)|
Get the safety chain connection devices for road trailers general circular.
Shackles may also be used on trailers over 3,500kg and up to 4,500kg as long as the rating of each shackle meets a minimum break load limit of 4,500kg.
For more information on suitable safety chain connection devices for trailers over 3,500kg contact the Vehicle Standards unit at the MVR.
Last updated: 17 February 2020
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