seatpost
Noun
Meaning
seatpost (plural seatposts)
Alternative spelling of seat post
Examples
The frame sits on top of the axle bearings, while the cranks attach to the ends of the axle, and the seatpost slides into the frame to allow the saddle to be height adjusted.
Usually have a relatively high seatpost, a narrow saddle, and a squared fork (used for one-footed tricks).