A method for alarming decrease in tire air-pressure in which decrease in
tire air-pressure is determined on the basis of rotational velocity
information of a wheel of a vehicle. Respective thresholds for
determining whether judgment of decrease in tire air-pressure is to be
made or not are changed depending on magnitude of driving torque of the
vehicle when the vehicle is performing turning movements. It is possible
to improve the detection accuracy without issuing an erroneous alarm even
in the case where a large driving force is applied when the vehicle is,
for instance, running on a climbing road or when it performs trailer
towing.
