25.4 mm seatpost (25.4 mm) vs 31.6 mm seatpost (31.6 mm): specs compared
Updated 05 September 2026.
3
specs differ
25.4 mm seatpost (25.4 mm) and 31.6 mm seatpost (31.6 mm) differ on 3 specs: diameter, designation, typical frames.
| Spec | 25.4 mm seatpost (25.4 mm) | 31.6 mm seatpost (31.6 mm) |
|---|---|---|
| Diameter | 25.4 mm (1 in) | 31.6 mm |
| Designation | 25.4 mm | 31.6 mm |
| Typical frames | BMX, older utility and one-piece-crank frames with a 1 in seat tube | many mountain bikes and gravel frames, older oversized road frames, and the other common dropper-post diameter |
Questions and answers
How do 25.4 mm seatpost (25.4 mm) and 31.6 mm seatpost (31.6 mm) compare?
25.4 mm seatpost (25.4 mm) and 31.6 mm seatpost (31.6 mm) differ on 3 specs: diameter, designation, typical frames.