A bicycle which sounds an audible signal on motion of the bicycle is described. The alarm system is totally self contained and appropriately attached to the frame of the bicycle. It contains critical delay circuits which gives the bicycle rider the opportunity to arm and disarm the alarm by a key switch without tripping the audible alarm. Additional circuitry prevents the audible alarm from remaining in an on state indefinitely after the alarm is tripped, thereby conserving battery power. Said bicycle includes a motion detection switching means, alarm timer means, limit means and oscillator means all conveniently contained in a compact package. Recent progress in the development of energy efficient audible alarms assures a loud signal on the impermissible motion of the bike.