T47 Threaded Bottom Bracket Compatibility

Also known as: T47 internal, T47 external, T47a, T47i

T47 was designed to solve the creaking of press-fit frames while keeping their large 46–47mm shell. It threads M47 × 1mm cups into a 47mm shell, so it accepts a full 30mm spindle internally while still being fully serviceable like BSA.

There are two families: T47 external (outboard bearings, like a BSA cup) and T47 internal (bearings sit inside the shell for a cleaner, wider stance). Frames and cups are cross-compatible as long as both are T47; our compatibility engine treats T47 internal and external as interchangeable. Thanks to the wide shell, a single T47 frame can run 24mm Shimano, SRAM DUB, 30mm and Campagnolo cranks by swapping the BB.

T47 at a glance

Fitment
threaded
Shell
47mm shell, M47 × 1mm thread
Shell width
68mm / 73mm / 85.5mm
Native crank
24mm (Shimano Hollowtech II)
Good to know: T47 internal and external share the same M47 × 1mm frame thread; the difference is only where the bearings sit.

T47 bottom brackets by crank fitment

A T47frame accepts different cranks depending on the bottom bracket you choose. Pick the group that matches your crankset's spindle.

Frames with a T47 bottom bracket

88 frames in our catalogue use the T47 standard.

Showing 48 of 88.

Cranksets that fit a T47 frame

These cranksets match a spindle standard a T47 bottom bracket supports.

Showing 24 of 202.

Frequently Asked Questions

Is a T47 bottom bracket threaded or press-fit?

T47 is a threaded standard: the cups screw directly into the frame (47mm shell, M47 × 1mm thread). Threaded shells are generally the most creak-free and serviceable, because no bearing is pressed into the frame itself.

What shell width does a T47 frame use?

T47 frames use a 68mm / 73mm / 85.5mm shell (47mm shell, M47 × 1mm thread). Always match your bottom bracket to both the standard and your frame's exact shell width before buying.

Which cranks fit a T47 frame?

With the right bottom bracket, a T47 frame can run cranks on several spindle standards. In our catalogue we have T47 bottom brackets for: 24mm (Shimano Hollowtech II); 30mm (BB30 / PF30 / 386EVO); Campagnolo Ultra-Torque (25mm); SRAM DUB (28.99mm); SRAM GXP (24/22mm). Pick the bottom bracket that matches your crank's spindle, most commonly 30mm (BB30 / PF30 / 386EVO).

How many T47 bottom brackets and frames are listed?

We currently track 37 T47 bottom brackets and 88 frames built to the T47 standard, checked against our compatibility engine.

Is T47 internal the same as T47 external?

They share the same M47 × 1mm frame thread, so a T47 frame accepts either. The difference is where the bearings sit: external bearings sit outboard (like a BSA cup), internal bearings sit inside the shell. Our compatibility engine treats T47 internal and external as interchangeable for the frame.

Can I convert a BSA frame to T47?

No. T47 uses a 47mm shell thread and BSA uses a 34.8mm (1.37") thread, so they are not interchangeable. You cannot re-thread a BSA shell to T47; the frame has to be built for it. Some press-fit frames (PF30/BB386) can be converted to T47 because they share the ~46mm bore.

Other bottom bracket standards

BSAItalianPF30BB86BB92BB386EVOBBright

Compare standards

Not sure it fits?

Add your frame, crank and bottom bracket to a build and we'll check the shell, thread and spindle automatically.

Open the Builder

37 T47 bottom brackets checked by our compatibility engine.