This International Standard specifies the characteristics of the 90 [89 mm (3,5") diameter] semi-trailer fifth wheel
kingpin used for coupling extra-heavy-duty vehicles exceeding the limitations of weight generally laid down by
It is applicable to fifth wheel kingpins intended for engaging 90 fifth wheels as defined in ISO 3842 .
This International Standard also specifies the dimensional characteristics required for mounting and
NOTE The dimensions of the 50 semi-trailer fifth wheel kingpin, normally used to couple semi-trailers to tractors in
compliance with mass limitations usually set by compulsory regulations, are given in ISO 337.