30.6 mm seatpost (30.6 mm) vs 30.9 mm seatpost (30.9 mm): specs compared
Updated 05 September 2026.
3
specs differ
30.6 mm seatpost (30.6 mm) and 30.9 mm seatpost (30.9 mm) differ on 3 specs: diameter, designation, typical frames.
| Spec | 30.6 mm seatpost (30.6 mm) | 30.9 mm seatpost (30.9 mm) |
|---|---|---|
| Diameter | 30.6 mm | 30.9 mm |
| Designation | 30.6 mm | 30.9 mm |
| Typical frames | some older oversized aluminium road and MTB frames | many mountain bikes and full-suspension frames, and one of the two common dropper-post diameters |
Questions and answers
How do 30.6 mm seatpost (30.6 mm) and 30.9 mm seatpost (30.9 mm) compare?
30.6 mm seatpost (30.6 mm) and 30.9 mm seatpost (30.9 mm) differ on 3 specs: diameter, designation, typical frames.