Patent ID: 7310997

Claim:
A tire warning device which detects tensile forces of at least one of reinforcing cords of a carcass ply or belt ply of a pneumatic tire and provides a warning on the basis of the tensile forces detected, comprising: a strain sensor adapted for attachment to the at least one reinforcing cord, the strain sensor sensing a strain of the at least one reinforcing cord; transmitting means adapted for transmitting a signal sensed by the strain sensor; receiving means adapted for receiving a sensed signal from the transmitting means; processing means adapted for calculating the tensile forces of the at least one reinforcing cord on the basis of the sensed signal input from the receiving means and for determining whether the warning is provided or not on the basis of the calculated tensile forces; and warning means adapted for providing the warning based on the determination of the processing means, wherein: the strain sensor is attached to at least one of reinforcing cords of the carcass ply in a sidewall portion of the tire, the processing means determines whether or not the ratio Ma/Mb of the minimum value Ma of the calculated tensile forces of the at least one reinforcing cord to a mean value Mb thereof or the ratio Ma/Mc of the minimum value Ma to the maximum value Mc thereof is less than a preset first threshold value, and the warning means provides the warning for notifying that the tire is in a state having a high risk of occurrence of tire breakdown if the processing means determines that the ratio Ma/Mb or the ratio Ma/Mc is less than the first threshold value.