Couplemate discuss Myths and facts abound around the campfire about shackles and safety chains. Below are a few facts with references and a few myths from the campfire.
- Dee or Bow shackles must be compatible with a rated safety chain, therefore it must be stamped with a rating. You may be called to proved your Dee Shackle is compatible. How do you do that? (CI-119C, Page 2, para 3)
- Each Chain must be sized such that the minimum breaking load exceeds the ATM. (VSB1 Page 27, para 4)
- Safety Chain must be stamped at intervals not exceeding 4 links. (CI-119C, Page 1, para 8)
- The Break Load Limit of the shackle must be 1.5t greater than the ATM. (CI-119C, Page 3)
- Existing unstamped safety chain need not be replaced on older trailers. (CI-119C, Page 3)
Comments: If shackles or dee shackles are not stamped, they are not compatible with your safety chain.
Statement: You only need one safety chain for trailers up to 2.5t. Over 2.5t, two safety chains must be used.
Fact: This is true
Statement: You need “coloured pin” i.e. yellow or red, rated shackle to comply with various state rules.
Fact: Myth, Trailer safety chains must be rated at or above the ATM of the trailer. Shackles must be marked or stamped with dee shackles that must be rated to the appropriate capacity of the chain. Both the chain and shackle must be stamped with a rating. Shackles need not be coloured.
Statement: Chains can be welded in any position on the drawbar.
Fact: Myth, Drawbar safety chain attachment points should not come into contact with the road surface. When the trailer is disconnected or detached from the vehicle.
Statement: Rated Dee shackles can be used on trailers up to 4.5t.
Fact: Myth, Dee shackles or Bow Shackles are used to attach the safety chain to chain holders, alternatively ½ of the link of safety chain can be welded to the trailer chassis up to 3.5t provided the mounting position does not cause the chain to come in contact with the ground when disconnected or detached. Trailers over 3.5t must use chain holders and Grade 80 safety chain.
Download the safety chain rules.
- Up to 2.5t trailers and caravans require one rated safety chain that can be welded or fixed to a chassis rail by an approved and rated hammerlock or similar device.
- 2.5t up to 3.5t trailers and caravans must have two safety chains that can be welded or fixed to a chassis rail by an approved and rated hammerlock or similar device.
- 3.5t to 7.2t safety chains must be Grade 80 and attached to the trailer and towbar using a high tensile 4140 pin.
- One safety chain required on trailer up to 2.5t – VSB1
- Two Chains required on trailer over 2.5t – VSB1
- Galvanised Chain is illegal over 3.5t
- The safety chains must be crossed under the tow bar receiver when attached to the tow bar.
- Each chain must be sized such that the minimum breaking load exceeds the ATM
- Working load is stamped on the chain or shackle. – VsB1
- Breaking load is six-times working load. – WA CI119C
- Drawbar safety chain attachments should not come into contact with the road surface when the trailer is disconnected. – VSB1
- Safety Chains must be permanently attached to the trailer, shackles are not permitted for trailers over 3.5t. QLD AIS 12(a)
- Rated Shackles approved as tow bar attachments over 3.5t, provided breaking load 1.5 times ATM – WA CI119C
- Rated Shackles are illegal as attachments on trailers over 3.5t – WA CI119C
- Stainless Steel Shackles are not permitted – WA CI119C
- Attachment points of both trailer and tow vehicle must be as near as possible to the coupling. QLD AIS 12(a)
- Herc-Alloy 800 is required chain for all trailers over 3.5t. (usually a coloured chain) QLD AIS 12(a)
Safety Chain attachment points – QLD AIS 12(a)
Each safety chain attachment point must be capable of withstanding the following minimum forces without incurring either residual deformation that would interfere or degrade the function of the assembly, or any breaks, cracks or separation of components:
Longitudinal tension and compression (N) 1.5 x 9.81 x ATM (in kg)
Vertical Tension and compression (N) 0.5 x 9.81 x ATM (in kg)
Furthermore, the tow bar attachment point on trailers under 3.5t is rated at 1/2 the rating of the tow bar. Therefore when upgrading over 3.5t these attachments point must be upgraded to EACH accommodate the full ATM.