Heavy Vehicle (Vehicle Standards) National Regulation

A fifth wheel coupling used in a B-double or road train must have a D-value complying with AS 1773-1990 ‘Articulated Vehicle—Fifth Wheel Assemblies’.

A turntable used in a B-double or road train must have a D-value complying with AS 1773-1990 ‘Articulated Vehicle—Fifth Wheel Assemblies’.

If a fifth wheel coupling used in a B-double or road train is built for a 50mm kingpin or 90mm kingpin, the coupling must—

meet the dimension requirements in AS 1773-1990 ‘Articulated Vehicle—Fifth Wheel Assemblies’; and

not be worn away more than recommended by the standard.

If a fifth wheel coupling used in a B-double or road train is built for a 75mm kingpin, the coupling must—

be compatible with a kingpin built as required by section 25(3)(a); and

not be worn so that it does not comply with subsection (5).

In testing a fifth wheel coupling used in a B-double or road train and built for a 75mm kingpin to decide whether its D-value complies with subsection (1), the longitudinal movement, after readjusting the jaws of the coupling using a kingpin built as required by section 25(3)(a), must not be more than 4mm.