A radio-type full-automatic leakage alarm for tyre of motor-driven vehicle is composed of a miniature radio transmitter fixed to air valve of tyre, a switch controlled by the air pressure in tyre and a radio receiver installed in the driver cab. When the air pressure in tyre is reduced to a threshold due to leakage, the switch is triggered to turn on the radio transmitter for transmitting leakage signal. The signal is received by the said receiver to generate an audio alarm which indicating corresponding numerals. |