Dee Shackle Tips to Select the Correct Size

Dee Shackle rating is often too high for caravans and trailers. Learn how to calculate the correct shackle size?

Your shackles must be of comparable size to your safety chain.

D 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

The best way to prove safety chain comparability is with a rated shackle or a stamped dee shackle.


All previously licensed (registered) trailers are acceptable with original chains supplied at the time of licensing providing they are in good condition, appropriately sized and are safely secured to the trailer.

Dee Shackle and Bow Shackles are rated to WLL which means Working Load Limit. WLL is stamped on the body of the shackles.

The WLL is located in AS2321. This standard is the Australian Standard for lifting purposes.

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

Dee Shackle BLL (Break Load Limit)

The BLL of a rated Shackle must be at least 1.5 x  the trailer ATM.

How to calculate BLL

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

A 2t shackle has a rating of 2 x 6 = 12t. Divide by 1.5t = 8t. Therefore, a 2t shackle is rated 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 required to connect your safety chains to your tow vehicle.

This regulation is a requirement for all trailers and caravans up to 3.5t.

Note: Bow shackles are a comparable replacement for Dee Shackles.

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

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


Vehicle Safety Standard WA