指定用于将底部支架外圈装配到自行车底部支架的螺纹轮廓、限制和公差。它基于ISO基本螺纹轮廓的使用、与相应B.S.C.螺纹的良好互换性、螺纹公差等级和公差位置的使用以及ISO 1502制造的量规的使用。

Specifies the thread profile and limits and tolerances for the screw threads used to assemble bottom bracket cups to bottom brackets on bicycles. It is based on the use of the ISO basic thread profile, satisfactory interchangeability with the corresponding B.S.C. thread, the use of screw thread tolerance grades and tolerance positions and the use of gauges made to ISO 1502.