BS 6102-9:1990

Committees responsible
National foreword
Specification
   Introduction
1 Scope
2 Normative references
3 Basic ISO thread profile and basic sizes
4 Limits and tolerances
5 Designation
6 Gauging system
Tables
1 Basic dimensions
2 Limits and tolerances for screw threads on cups
3 Limits and tolerances for screw threads on bottom
   bracket shell
4 Cup - Limits of size for GO screw ring and calliper
   gauges, and associated screw check, wear and setting
   plugs
5 Cup - Limits of size for NOT GO screw ring and
   calliper gauges, and associated screw check, wear and
   setting plugs
6 Shell - Limits of size for GO and NOT GO screw plug
   gauges
7 Cup and shell - Limits of size for GO and NOT GO
   plain ring or calliper gauges for cup major diameter,
   and GO and NOT GO plain plug gauges for shell minor
   diameter
Figures
1 Basic profiles of British Standard Cycle and ISO
   threads
2 Thread profiles and tolerance zones for ISO bottom
   bracket shell and cup threads

Specifies the thread profile and limits and tolerances for the screw threads used to assemble bottom cups to bottom brackets on bicycles (adjustable cups with right hand thread, fixed cups with left hand thread).

This International Standard specifies the thread profile and limits and tolerances for the screw threads used to assemble bottom bracket cups to bottom brackets on bicycles (adjustable cups with right-hand thread, fixed cups with left-hand thread). It is based on

1. the use of the ISO basic thread profile given in ISO 68;
2. satisfactory interchangeability with the corresponding British Standard Cycle (B.S.C.) thread; this has required the use of an inch pitch (t.p.i.);
3. the use of screw thread tolerance grades and tolerance positions given in ISO 965-1;
4. the use of gauges made to ISO 1502.