Last week, Standards Australia released a draft of updates to AS 4177 for public comment. The standard was prepared by Standards Australia Committee ME-052, (Caravan and Light Trailer Components), and is intended to supersede the current package of five standards (AS 4177.1-5) originally released in 2004.
While the objective of the standard is to specify requirements for towing components intended for towing trailers and caravans of up to 3.5-tonne Aggregate Trailer Mass (ATM), it also includes some requirements for tow-balls, coupling bodies and for vehicles where the Gross Vehicle Mass (GVM) of the towing vehicle exceeds five tonnes.
On that basis, it is relevant to HVIA members that supply vehicles fitted with tow-bars and towing brackets suitable for use with 50-mm tow-balls, shank-type 50mm tow-balls, coupling bodies for ball couplings suitable for use with 50mm tow-balls, safety chains and their connectors, the suppliers of that equipment, and the suppliers of electrical connectors for those types of vehicles.
The draft is available to download here, but interested persons wishing to make comments or provide feedback on it will need to create a free Standards Australia account, which can be done here.
The major changes in the draft are:
>> The amalgamation of the five parts of AS 4177 into one document;
>> The addition of safety chain connectors;
>> The addition of different performance requirements for tow-balls and coupling bodies where the towing vehicle is over five-tonne GVM;
>> The expansion and clarification of coupling-body requirements, including loading, ball pull-out, protective coatings, hazardous projections and installation information;
>> Stricter definitions of the contact functions of electrical connectors;
>> Expanded electrical connector voltage to 12-volt, 24-volt and 48-volt systems; and
>> The revision of electrical connector requirements using performance criteria to allow more design freedom whilst retaining backward compatibility.
HVIA understands that the new standard’s requirements are likely to make an old NHVR Vehicle Standards Guide defunct but is awaiting feedback from the regulator on that point.
VSG 16 (released in 2024) recommended limiting the trailer ATM when 50-mm tow-balls are used on vehicles with more than five tonnes GVM. HVIA believes that the addition of a D-value requirement to the new standard for tow-balls used in such applications addresses that issue.
The public consultation period is open until December 29, 2026. Please contact HVIA Chief Technical Officer Adam Ritzinger at a.ritzinger@hvia.asn.au to discuss.