A fluid-containing bag of sheet material mounted on the radially inner surface of a stabilizer ring as by an adhesive or metal clips for retaining fluid during normal inflated operation of the tire and releasing the fluid in response to rotation of the tire tread portion in engagement with the radially outer surface of the stabilizer ring. The fluid may be released by an increase in temperature softening a plug in the wall or the adhesive in a seam between walls of the bag. The fluid may also be released by the rupture of a flexible tube extending from the bag to the radially outer surface of the stabilizer ring.