Safety Chains for Trailers: Rules and Correct Fitting

Safety chains are one of the most critical components of your trailer's attachment system. They're your backup security measure if the main coupling fails, preventing your trailer from becoming a hazard on Australian roads. Whether you're towing a horse float, caravan, or utility trailer, understanding the rules and proper installation is essential.

Why Safety Chains Matter

Safety chains serve a single but vital purpose: they keep your trailer connected to your vehicle if the primary coupling mechanism fails. This could happen due to corrosion, mechanical failure, or a serious accident. Without properly fitted safety chains, a detached trailer could cause a catastrophic accident, endanger other road users, and result in significant legal penalties.

Australian Legal Requirements

Australia has strict regulations governing safety chains under the Road Safety (Road Rules) Regulations. Here are the key requirements:

Mandatory Installation: All trailers manufactured after 1 July 1988 must be fitted with safety chains. Even if your trailer is older, it's strongly recommended to install them.

Chain Grade and Strength: Safety chains must have a minimum breaking strength equal to the Tare weight of the trailer, or 1.5 times the Gross Tare Mass (GTM), whichever is greater. Most trailers require Grade 70 chains (minimum).

Number of Chains: At least two safety chains must be fitted. For heavier trailers (over 750 kg ATM), you may need additional chains depending on your state's regulations.

Attachment Points: Chains must be securely attached to the trailer frame at points that can withstand the required load. Never attach to the drawbar ball or coupling socket alone.

Correct Fitting Procedures

Step 1: Select the Right Chain Choose Grade 70 or Grade 80 chain with appropriate diameter (typically 6–8 mm for most trailers). Ensure it has a breaking strength that meets or exceeds your trailer's specifications. Check your trailer's manual or compliance plate for exact requirements.

Step 2: Locate Secure Attachment Points Identify two strong points on your trailer frame, ideally on opposite sides or positioned to prevent twisting. These should be structural members that won't deform under load. Avoid attaching to any non-structural components.

Step 3: Measure and Cut to Length The chain should be long enough to allow normal steering and turning but short enough that it won't drag on the road or tangle. A good rule of thumb: the chain should reach from the trailer attachment point to the tow vehicle's attachment point when the trailer is in a fully turned position (about 45 degrees).

Step 4: Install Shackles or Hooks Use rated shackles or heavy-duty hooks to connect the chain to both the trailer and tow vehicle. Bow shackles are preferable because they distribute load evenly. Ensure all fasteners are tightened securely and use lock washers to prevent loosening.

Step 5: Attach to the Tow Vehicle Connect the chains to anchor points on your vehicle—typically provided loops or reinforced chassis points. Consult your vehicle's manual for correct attachment locations. Never attach to bumpers or other non-structural parts.

Step 6: Cross the Chains For maximum safety and stability, cross the chains underneath the drawbar (if space allows). This prevents the trailer tongue from dropping to the road if the coupling fails.

Maintenance and Inspection

Regularly inspect your safety chains for signs of wear, corrosion, or damage. Look for:

Rust or pitting that reduces chain strength
Stretched or bent links
Damaged shackles or attachment points
Cracks in welded areas of the trailer frame

Clean chains periodically and apply a light coat of oil to prevent rust. Replace any damaged components immediately—safety chains are not an area to compromise.

Common Mistakes to Avoid

Using chains that are too short, restricting steering
Attaching chains to the drawbar ball instead of the frame
Failing to cross chains beneath the drawbar
Using damaged or corroded chain
Neglecting to tighten fasteners properly
Installing only one chain instead of two

Professional Help

If you're unsure about your trailer's specific requirements or installation, consult a professional trailer repair specialist. Many Australian trailer repair workshops can inspect your current setup, assess compliance, and install or upgrade safety chains to meet regulations.

Safety chains are a small investment with enormous potential impact. They demonstrate your commitment to safe towing and protect everyone sharing the road with you.