Patent ID: 8554402

Claim:
A method of detecting a tire having a decreased internal pressure by making a relative comparison among wheel speeds of tires attached to respective wheels of a vehicle, comprising: a step of detecting wheel rotation information regarding the respective tires of the vehicle; a step of calculating wheel speeds based on the detected wheel rotation information; a step of calculating DEL2 as a decreased pressure determination value by comparison between a front wheel speed and a rear wheel speed; and a step of determining, when the resultant decreased pressure determination value exceeds a predetermined threshold value, that a tire has a decreased internal pressure, wherein the method further comprises a threshold value setting step of setting the predetermined threshold value based on (a) a relation obtained in advance, depending on a difference of the mass of the vehicle, between DEL2 and a load sensitivity during a vehicle turning, and (b) the load sensitivity obtained by a turning at the time of determination.