To provide inexpensive tire partition walls of a simple structure which allow a driver to perceive abnormality in a running tire and quickly initiate a means for avoiding a burst of the tire, thus eliminate a concern of the burst of the tire in any place where a vehicle is running.

The open type partition walls 1 of the same material as the tire are formed circumferentially at several spots at an identical interval on the inner wall of the tire so as to keep the balance of the tire on run intact. When the air pressure of the tire decreases, the part without the partition walls 1 yields under the vehicle weight to extend laterally, but the ground surface of the spots where the partition walls 1 are formed does not extend laterally due to the hardness and resistance of the partition walls 1, retaining the same shape as it has under normal air pressure. As the vehicle runs, therefore, the tire ground surface deformed under the vehicle weight and that retaining the same shape revolve alternately, at which the hardness of the partition walls 1 produces abnormal vibrations or grounding sounds. The driver senses those vibrations and sounds, perceives an air pressure decrease, and prepares for avoiding a burst of the tire.