RV FEATURE
SAFETY CHAINS
Safety chains are compulsory across Australia . They are designed to maintain a physical connection between the caravan and tow vehicle in the event the tow ball , coupling or related component fails , while also preventing the drawbar from ploughing into the bitumen .
All trailers with an ATM of less than 2500kg ATM must be fitted with at least one safety chain , while all trailers with an ATM of 2500kg and above must have two fitted . Further , for trailers with an ATM of up to 3500kg ( the vast majority of Australian-made caravans but not all ), the chains must comply with AS4177-4 and have a rating that ’ s at least equal to the ATM of the trailer .
The safety chains must be attached to the trailer in a permanent fashion ( i . e ., they can ’ t be shackled ). When the trailer is below 3500kg ATM , the chains may be welded to the drawbar .
Safety chains must also be stamped with their capacity , along with the digits 4177 , showing that they comply with the Australian Standard .
AS4177 stipulates the following diameters for the steel :
• Up to 1000kg : 6.3mm ;
• Up to 1600kg : 8mm ;
• Up to 2500kg : 10mm ; and
• Up to 3500kg : 13mm .
Note : although they are rarely used by caravan manufacturers , safety cables , rather than chains , are permissible for trailers up to 3500kg ATM , provided they are appropriately rated .
THE TOW BAR
This is the framework that supports the trailer and connects it securely to the tow vehicle . It sounds obvious , but safe and legal towing requires a tow bar that ’ s been properly designed and fitted . And like almost every other component related to towing , it requires a rating , and for that rating to be clearly and permanently displayed on the assembly , along with the make and model of the vehicle for which it is intended .
Typically – but not always – the tow bar will be rated at 10 per cent of the vehicle ’ s overall towing capacity . For example , a tow bar designed for a vehicle rated to tow 3500kg will be rated to accept a 350kg load .
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