Anti-theft device for two-wheel vehicles

An anti-theft system for a two-wheel vehicle having a wheel with a tire and apertures through the wheel, the system comprising:

• a housing configured to be positioned adjacent to a surface of the tire with the housing generally perpendicular to a plane of the wheel;
• a fixed, curved clamping arm rigidly coupled to the housing and configured, when the housing is positioned adjacent the tire surface, to extend through one of the apertures of the wheel;
• a movable, curved clamping arm slidably received in the housing and movable between a retracted position in which the movable clamping arm is contained within the housing and a deployed position in which the movable clamping arm extends from the housing toward a free end of the fixed, curved clamping arm to at least partially enclose the wheel between the fixed and movable clamping arms and thereby limit rotation of the wheel;
• a locking-and-unlocking structure disposed in the housing and configured, in a locked state, to prevent retraction of the movable, curved clamping arm from the deployed position and, in an unlocked state, to permit free extension and retraction of the movable, curved clamping arm;
• and
• a motion-detection-and-alarm subsystem disposed in the housing and configured, when activated, to detect at least one of movement of the housing and vibration applied to the system and, in response, to drive a sound transducer to emit an audible alarm.