This invention is directed at a bicycle lock which is positioned within the frame, front riser post or seat support post, of the bicycle and secure from external compromise by ordinary handtools. In one embodiment, a key actuated slotted rotary engagement locking disk selectively engages and disengages a slotted locking disk affixed to the axle of the pedal crank. In another embodiment, a key actuated rack and pinion combination cooperates with a slotted disk on the pedal crank axle to lock and unlock the pedal crank. In another embodiment of the invention a supplemental external locking system for locking the bike to a post or the like is provided which is used in conjunction with the internally positioned locking systems.