Bottom bracket shell types

Press-fit bottom bracket shells are not threaded; instead the bearings or cups are pressed into the frame. This document details the critical factors that differentiate one press-fit standard from another.

The table at the bottom of the page is useful for quick comparisons.

BB30

• Shell width will measure 68mm (road) or 73mm (mountain)
• Shell inner diameter (ID) will measure 42mm; BB30 bearings have a corresponding outer diameter (OD) of 42mm
• Bearings press directly into the frame and stop at removable snap rings; two snap ring grooves will be present inside the shell
• Designed for BB30 30mm spindle cranksets; adaptors are available that permit the use of 24mm spindle cranksets (i.e. Hollowtech II, GXP)

PressFit 30 (PF30)

• Shell width will measure 68mm (road) or 73mm (mountain)
• Shell ID will measure 46mm
• Both PressFit 30 and BB30 use the same 30mm ID bearings and 30mm spindle cranksets; the difference is that PF30 bearings are contained inside cups and the cups are pressed into the frame
• The shell will have a smooth bore (no snap ring grooves); the outer lip of the cup contacting the frame is what stops the press action
• Designed for BB30 30mm spindle cranksets; adaptors are available that permit the use of 24mm spindle cranksets (i.e. Hollowtech II, GXP)

BB86/92

• Shell width will measure 86.5mm (road) or 91.5mm (mountain)
• Shell ID will measure 41mm
• Bearings are contained inside cups which are pressed into the frame; shell has a stepped design but there are no snap ring grooves
• Designed specifically for 24mm spindle cranksets originally intended for external threaded cups (i.e. Hollowtech II, GXP)

BB90/95

• Currently used exclusively on Trek bicycles
• Shell width will measure 90.5mm (road) or 95.5mm (mountain)
• Shell ID will measure 37mm
• Bearings press directly into the frame and stop at an integrated raised step inside the shell bore; snap rings are not used
• Designed specifically for 24mm spindle cranksets originally intended for external threaded cups (i.e. Hollowtech II, GXP)

BBright Direct Fit

• Currently used exclusively on Cervelo bicycles
• Shell width will measure 79mm (road standard only)
• Shell ID will measure 42mm
• BBright Direct Fit is a variant of BB30 with an asymmetric wider shell (11mm offset to the non-drive side); bearings press directly into the frame and stop at removable snap rings.
• Accepts standard BB30 bearings but the wider shell requires a BBright-compatible crankset

BBright Press Fit

• Currently used exclusively on Cervelo bicycles
• Shell width will measure 79mm (road standard only)
• Shell ID will measure 46mm
• BBright Press Fit is a variant of PF30 with an asymmetric wider shell (11mm offset to the non-drive side); bearings are contained inside cups and the cups are pressed into the frame
• Accepts standard PF30 cups for but the wider shell requires a BBright-compatible crankset; adaptors are available that permit the use of 24mm spindle cranksets (i.e. Hollowtech II, GXP)

386 EVO

• Shell width will measure 86.5mm (road standard only)
• Shell ID will measure 46mm
• 386 EVO is a variant of PF30 with a wider shell; bearings are contained inside cups and the cups are pressed into the frame
• The shell will have a smooth bore (no snap ring grooves); the outer lip of the cup contacting the frame is what stops the press action
• Accepts standard PF30 bottom bracket cups but the wider shell requires a 386 EVO-compatible crankset

OS BB

Press-Fit Bottom Bracket Comparison