Shell Pf30a vs Shell Osbb: specs compared
Updated 05 September 2026.
3
specs differ
Shell Pf30a and Shell Osbb differ on 3 specs: shell inside diameter, shell width, thread.
| Spec | Shell Pf30a | Shell Osbb |
|---|---|---|
| Type | press fit | press fit |
| Shell inside diameter | 46 mm smooth press-fit bore | 42 mm bore (alloy, BB30 style) or 46 mm bore (carbon, PF30 style) |
| Shell width | 73 mm (asymmetric, for Cannondale Ai offset rear) | 68 mm (road) and 73 mm (MTB) |
| Thread | none, cups press into the 46 mm bore | none on the carbon 46 mm and alloy 42 mm shells; OSBB is a Specialized name, not a separate thread |
| Crank spindles it hosts | 30 mm native; 24 mm Shimano and 28.99 mm DUB need a reducer | 30 mm native; 24 mm Shimano and 28.99 mm DUB need a reducer |
Questions and answers
How do Shell Pf30a and Shell Osbb compare?
Shell Pf30a and Shell Osbb differ on 3 specs: shell inside diameter, shell width, thread.