Abstract: The present invention relates to locking devices and in particular to apparatus and methods for securing components to a bicycle frame (60). A first exemplary embodiment of a locking device (100) includes a first retainer (120), a second retainer (170) and a key (190). The first retainer (120) includes a coupler (124) which is configured to couple with a coupler (196) on key (190). The first retainer (120) further includes a first radial surface (130) having a frusto-conical configuration. The second retainer (170) includes a tab member (174) configured to prevent the rotation of the second retainer (170) relative to the bicycle frame (60). In a second exemplary embodiment of a locking device (300) includes a first retainer (320), a sleeve (360), a second retainer, and a key. The first retainer (320) includes a coupler (324) which is configured to couple with a coupler on the key.