本国际标准规定了直径为90[89 mm（3,5”）的半挂车备用轮的特性 用于连接超重型车辆的主销，其重量超过了制造商通常规定的限制 官方要求。 适用于ISO 3842[1]中定义的用于啮合90个备用轮的备用轮主销。 本国际标准还规定了安装和安装所需的尺寸特性 互换性。 请注意50号半挂车备用轮主销的尺寸，该主销通常用于将半挂车连接到拖拉机上 ISO 337[2]给出了通常由强制性法规设定的质量限制的符合性。

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 official requirements. It is applicable to fifth wheel kingpins intended for engaging 90 fifth wheels as defined in ISO 3842 [1]. This International Standard also specifies the dimensional characteristics required for mounting and interchangeability. 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[2].