Abstract: A locking member for releasably securing a bicycle to a carrier on a motor vehicle. The locking member can be quickly and easily slid onto a support arm of the carrier, adjustably positioned along the length of the support arm, and releasably secured to the arm by a simple rotational movement of an eccentric locking sleeve. The device includes an upper channel surface, surrounding the locking sleeve, on which the top tube of the bicycle frame rests and a second rigid pivotal member with a releasable strap engaging either the seat or down tube of the bicycle frame. The pivotal attachment of the first and second rigid members allows virtually any angular relationship between the members so as to securely engage the respective tubes of the bicycle frame.