Abstract: An alarm system for automotive wheel rims includes a magnet mounted to each wheel rim mounted substantially at the wheel rim's central axis. Each wheel hub includes a magnetic field sensor for sensing the movement of an adjacent magnet. Each magnetic field sensor is connected to a central processor for transmitting an alarm signal in the event that an adjacent magnet has moved indicating that a wheel rim has been displaced. The central processor triggers an audible or visual alarm alerting persons that a wheel rim has been removed without authorization.