To reliably and quickly detect the increased inner pressure of a tire and to inform a driver of abnormailities of the tire by mounting projections made of rubber in the bottom in the circumferential direction of rim so as to detect the decreased inner pressure of the tire and to generate vibrations as an alarm.

A tire wheel comprises a wheel 3 having a rim 1 and a disk 2, and a tire T mounted to the rim 1. The tire T has decreased inner pressure alarming devices A therein. The devices A are spaced about 180° opposite to each other in the bottom in the circumferential direction of the rim 1. They are composed of two projections 6 made of rubber which comprises base parts and cover parts. The surface shape of the cover part is made a curved plane shaped like a dome projecting outside in the radial direction thereby to detect the force from the road via the tire T having the deflection caused by the decreased inner pressure of the tire T and to inform a driver of abnormalities by generating vibration as an alarm signal.