Shell Bb30 vs Shell Bb30a: specs compared
Updated 05 September 2026.
3
specs differ
Shell Bb30 and Shell Bb30a differ on 3 specs: shell width, thread, crank spindles it hosts.
| Spec | Shell Bb30 | Shell Bb30a |
|---|---|---|
| Type | press fit | press fit |
| Shell inside diameter | 42 mm smooth press-fit bore | 42 mm smooth press-fit bore |
| Shell width | 68 mm (road) and 73 mm (MTB) | 73 mm (asymmetric, 5 mm wider on the non-drive side) |
| Thread | none, two 6806 bearings press directly into the 42 mm bore | none, two bearings press directly into the 42 mm bore |
| Crank spindles it hosts | designed around a 30 mm spindle; 24 mm and 28.99 mm cranks need a reducer | 30 mm native; 24 mm Shimano and 28.99 mm DUB need a reducer |
Questions and answers
How do Shell Bb30 and Shell Bb30a compare?
Shell Bb30 and Shell Bb30a differ on 3 specs: shell width, thread, crank spindles it hosts.