Type of BB shell

The difference of all kinds of BB shell in the frame

A, gauge thread, thread is normal thread, outer diameter 36mm, tooth distance 36 ≤ 24TP. It is very rare and needs to be matched with a special rule center shaft.

B. The standard thread of BSA is a positive and negative, with an outer diameter of 34.798 mm and a tooth pitch of 1.37 * 24TPI. The five-pass width is mostly 68 and 73 mm. One of the most traditional five-way standards.

titanium road bike frame4

C, the pressed BB30,30 represents the diameter of the disk axis-30mm (the axial diameter of the integrated disk represented by Shimano is 24mm). The width of the five links is 68 mm and the inner diameter is 46 mm. The traditional British thread five usually has a width of 68 mm.


D,Press-in BB90, actually the frame five-way width has 89.5mm and 92mm. the inner diameter is 41 mm.

E, pressed BB86, was developed on the basis of BB90, which is only 86.5 mm in width. Most of them still use ordinary integrated dental plates.

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