What bottom bracket fits my frame? (BB30 / T47 / BSA / PressFit)

Bottom bracket (BB) compatibility is one of the most confusing parts of bike building. There are many overlapping standards, and frames don't always make it obvious which one they use.

This guide is a starting point for narrowing down what you have. Always confirm with your frame manufacturer's spec sheet before buying — internal diameters and shell widths are not always visible by eye.

The most common standards

Threaded

• BSA / English — 68mm or 73mm wide, threaded shell. The classic standard. Very serviceable, well-supported.
• T47 — Wider (47mm) threaded shell. Combines the reliability of threaded BBs with more room for larger spindles.
• Italian — 70mm wide, threaded. Mostly older Italian frames.

Press-fit

• BB30 / PF30 — 30mm spindle, press-fit bearings.
• PressFit 86 / 92 — Wider press-fit shell, 24mm spindle (Shimano-style).
• BB386EVO — Wider shell + 30mm spindle (a hybrid of BB30 and PF86).

How to identify what you have

1. Check the frame's spec page. This is the most reliable source.
2. Look at the existing BB if installed — markings on the cup will usually identify the standard.
3. Measure the shell width with calipers (68mm, 73mm, 86.5mm, 89.5mm, 92mm are all common).
4. Note the inner diameter — threaded vs press-fit, and 30mm vs 41/42mm vs 47mm bore.

If you're unsure, send us a photo of the BB shell with measurements and we can usually identify it.

Crank-to-frame matchups

Cranks are designed around a specific spindle diameter (commonly 24mm Shimano-style or 30mm). A given frame can often accept multiple crank standards via different BB cups, but not always. Some combinations need adapters; others are not advisable.

When in doubt

• Ask before buying. A wrong BB standard is one of the most common returns we see.
• Ceramic vs steel bearings is a separate decision from the standard. Either works in any standard.

Need a specific BB? Browse bottom brackets or send us a message with your frame model.