This Standard specifies minimum requirements for fifth wheel assemblies suitable for 50 mm and 90 mm kingpins for articulated vehicles including B-doubles and road trains in normal use on both sealed and unsealed roads. The requirements cover dimensional standards for interchangeability, strength testing and rating.NOTES:1 Additional components not specified or supplied by the fifth wheel manufacturer for a typical installation but necessary for a specific installation (e.g. attachment brackets) are not covered by this Standard.2 Requirements for the installation of fifth wheel assemblies on prime movers are given in AS 1771.3 Guidance on the selection of fifth wheel assemblies is given in Appendix A.4 Criteria for 50 mm and 90 mm kingpins are specified in AS 2175.5 Design criteria for trailer skid plates are specified in AS 4235.