5.3t WLL G80 Hammerlock (13mm)

Part No: CM551-1Y Category:


39 in stock

G80 Hammerlocks are used as chain connectors for trailers, caravans, and campers. Couplemate™ generally supplies this 13mm our drawbar chain kits for up to 3.5t ATM.

✓ Forged from high-tensile alloy steel (Grade 80).
✓ Working Load Limit (WLL) of 5.3t.
✓ Compliant with AS3776.

Test certificates available upon request.

39 in stock

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5.3t WLL G80 Hammerlock Safety Chain Connector

G80 Hammerlock connects galvanised 8mm, 10mm and 13mm safety chains to a trailer or dee shackle on the towbar.

Also, using hammerlocks shackles to join your trailer chain or to lengthen your chain is permitted.

A hammerlock connects the safety chain to the chain holder on the caravan chassis rail.

Hammerlock Features

  • The Hammerlock connects a grade 80 chain to an oblong link, hook, or other components.
  • Traditional design in a yellow or red powder-coated finish.
  • Each connecting link and each Hammerlock or body half shall not have, in use, more than one load-bearing component or chain.
  • Always allow for sufficient articulation and avoid over-crowding to ensure the load will be transmitted axially.
  • Ideal for a wide range and moving applications.
  • Connects chain to trailers or connects dee shackles to tow bars.
  • Australian standard: AS 3776 – Grade 80 Lifting Chain & Fittings.

Shackle Dimensions

Please refer to the technical drawing.

  • A – 29mm
  • B – 15mm
  • L – 117mm
  • K – 87mm
  • H – 15mm

G80 Hammerlocks are available in two other sizes:

The trailer chain hammerlocks above are not interchangeable with different-size chains. For example, a 2t Hammerlock will not fit a 10mm chain because the chain link is too small for the Hammerlock to pass through.

Hammerlocks Fit

Is your trailer or caravan chain too short?

The solution

  • Cut the trailer chain from your chassis rail, leaving one welded link on the chassis.
  • Install a new piece of rated galvanised 10mm longer chain. This chain is 64cm long.
  • Connect the Hammerlock to the new chain and the welded link on the chassis rail.

What you cannot do

  • Join the safety chain with dee or bow shackles until you reach the desired length.
  • Insert un-rated safety chain links.

Galvanised chains and shackles are illegal on all trailers OVER 3.5t.

Purchase safety chain here

Essential Reading

For trailers up to 3.5 tonnes ATM, the safety chain attachment can be done by welding. The weld must extend around 50% of the circumference of the link, and the adjoining link must have free movement.

For trailers of over 3.5 tonnes ATM, safety chain attachment must not involve welding or deformation of the chain.

Note: The welded chain link is not rated. The welded chain is considered a link or a chain holder.

Trailers up to 2.5 tonnes ATM must have at least one safety chain complying with AS 4177.4 – 1994 (Trailer and light trailer towing components – Safety chains up to 3.5 tonnes capacity) or as amended from time to time. This standard allows for steel safety chains by the following:

  • Up to 1.0 tonne, a chain size of 6.3 mm;
  • Up to 1.6 tonnes, a chain size of 8 mm;
  • Up to 2.5 tonnes, a chain size of 10 mm.

Trailers over 2.5 and up to 3.5 tonnes ATM must have two safety chains complying with AS4177.4 – 1994 or as amended occasionally. This standard allows for steel safety chains by the following:

• Up to 3.5 tonnes, a chain size of 13 mm.

The fitting of safety chains to trailers with a Gross Trailer Mass (GTM) greater than 2.0 tonnes and a brake system that automatically applies if the caravan becomes detached from the towing vehicle is optional.

Safety Chain Legislation up to 4.5t

Purchase spare parts and attachments for Dee Shackles

Additional information

Weight0.65 kg
Dimensions10 × 6 × 2 cm
Working Load Limit (WLL)



High-Tensile Alloy Steel (G80)



Our Service Lifetime Warranty

Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.

Couplemate™ is a manufacturer and vendor of high-quality towing, trailer, and caravan components. Couplemate™ Core Goods and Custom Work are guaranteed to be free of defects for the service lifetime of the product when used as intended.

Warranties are non-transferrable and Couplemate™ requires satisfactory proof of purchase prior to issuing a remedy. The full Couplemate™ Warranty Policy can be found in the Terms & Conditions: Section 8 – Consumer Guarantees & Warranty.

Warranties are in addition to your rights under the Australian Consumer Law. If something is wrong with your order, please contact our team.

60-Day Returns

After 60 years of experience, we know that life has its unpredictable moments.

All Couplemate™ orders (online, over the phone, or in-store) have a 60 day period for change-of-mind returns and exchanges. There are some items that can’t be returned and some returns may incur a 15% restocking fee.

You can view our full policy for change-of-mind returns here.


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