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Safety Chain Tips: Selecting the Correct Shackles

by | Apr 18, 2017 | Repairs & Maintenance | 0 comments

Dee Shackle Tips to Select the Correct Size

Firstly, Dee Shackle rating above one tonne is too high for caravans and camper trailers. So, how do you calculate the correct shackle size?

National legislation requires shackles to be of comparable size to the safety chain as suitable.

Dee shackle sizes and ratings are:

  • 5/16″ – 0.75t WLL – 3t Trailer Chain Rating – 11mm Pin
  • 3/8″ – 1t WLL – 4t Trailer Chain Rating – 11mm Pin
  • 7/16″ – 1.5t WLL – 6t Trailer Chain Rating – 13mm Pin
  • 1/2″ – 2t WLL – 8t Trailer Chain Rating – 16mm pin

A stamped dee shackle proves safety chain compatibility.


All previously registered trailers are acceptable with original chains supplied at the time of licensing. So, providing they are in good condition, an appropriate size and are safely secured to the trailer.

Dee Shackle and Bow Shackles are used as lifting equipment and rated to WLL which means Working Load Limit. Consequently, you will find WLL on the body of the shackles.Rated Bow Shackle

The WLL is located in AS2321. Furthermore, this standard is the Australian Standard for lifting applications.

Click here to view an article on Dee Shackles and the safety chain.

Dee Shackle BLL (Break Load Limit)

Within the trailer and caravan industry, we convert the WLL of a shackle or lifting device to the Break Load Limit. As a result, the BLL of a rated Shackle must be at least 1.5 x  the trailer ATM.

How to calculate BLL

You can find the BLL (Break Load limit) by multiplying the WLL (Stamped Load) x 6. Therefore, a 1t Stamped shackle has a BLL of 6t.

A 2-tonne shackle has a rating of 2 x 6 = 12t. Divide by 1.5t = 8t. Therefore, a 2t shackle is suitable to a max ATM 8t trailer

Finally, divide 6t by 1.5 = 4t (note above). Therefore, a 1 tonne Dee Shackle with a pin of 10mm would be suitable for trailers up to 4t.

References: WA Vehicle Safety Standards CI-119C

Shackles of comparable size to the safety chain are necessary to connect your safety chains to your tow vehicle.

This regulation is a requirement for all trailers and caravans up to 3.5 tonnes. Also, Bow shackles are a comparable replacement for Dee Shackles.

Furthermore, a breakaway kit is also be required for trailers and caravans over 2t.

If you are experiencing difficulty with the stamping or rating of Galvanised Dee Shackles. I invite you to contact, email or leave me a comment.



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