Seat tube assembly for bicycle

摘要

A seat tube assembly (10) for bicycles includes a seat tube (20) and a seat post (30) telescoped in the seat tube (20). Altitudinal adjustment of the seat post (30) with respective to seat tube (20) is possible by making a cable (55) draw a driving arm (53) to work with an auxiliary pusher (54) to push a trigger lever (52) so that the trigger lever (52) pushes a valve stem (44) to perform linear displacement, thereby establishing or cutting an oil circulation in a valve seat (42).