A handlebar stem provides a cylindrical quill tube having a hollow upper end and a lower end adapted to be placed snugly within a steering tube. The lower end has press fit thereon an insert having an external portion with an outer diameter substantially equal to that of the quill tube. The lower edge of each of the insert and quill tube are cut such that it defines an ovular plane through both the insert and quill tube. The lower end engages flushly with a similarly cut expander bolt having a cylindrical outer surface of substantially similar outer diameter to that of the quill tube and insert. The expander bolt is axially joined to the insert by means of a screw placed through the insert and into a threaded hole in the expander bolt with the head of the screw abutting an uppermost surface of the insert within the quill tube.