The FG thread table contains the dimensions for the bicycle thread in accordance with DIN 79012. The bicycle as a means of transportation has a history of around 200 years, during which time very different types of thread have become established in different regions. The bicycle thread according to the FG thread table is one of several attempts to bring structure to the construction of bicycles through standardization. In addition to the German DIN thread according to the FG thread table, there are also English, French and Italian standards, for example.
The bicycle thread from the FG thread table was designed for the high loads to which threads on bicycles are exposed. It can be found in various places, but primarily where the thread has to meet enormous demands. These include spokes and nipples, but sometimes also the bottom bracket shells or the axles. In addition to the thread according to the FG thread table, the metric thread M or the valve thread can also be found on bicycles.
The FG thread has a flank angle of 60° - something it has in common with many other bicycle standards. This also presents a certain pitfall, as the correct thread standard is not always immediately obvious when working on a bicycle and the high degree of similarity can quickly lead to confusion. It is therefore advisable to proceed with caution when using the FG thread table and never try to force a screw connection.
The table for the FG thread contains ten entries. The thread designation consists of the abbreviation Fg and the outside diameter. However, the numerical value is rounded, as the FG thread table often contains information on the outside diameter in mm with three decimal places, which would be impractical for the thread designation. In addition to the outer diameter, you will also find the core hole diameter in mm in the bicycle thread table. The pitch is specified in the FG thread table in threads per inch. We have also converted this value into mm for easier use.