Bottom bracket -How to DIY your bike with good carbon frame

Bottom bracket 

Ooh boy, here’s where it gets complicated. There are many bottom bracket standards.

Threaded bottom brackets: These are typically English threaded, a.k.a. BSA. Bottom bracket shells are either 68mm (typically road or gravel) or 73mm wide (often MTB). Fun fact: BSA stands for Birmingham Small Arms!

Press-fit bottom brackets: There are many standards here, such as BB30, PF30, BBRight, and BB90. Generally speaking, the bearings are all pressed into the frame, not threaded. Above all, check your frame’s spec and match it to the correct bottom bracket before ordering.