in the cylindrical center section 16 and extends through the interior portion of the beaded end sections 20 and follows the contour of the bladder liner 31 in the cylindrical center section 16 the first segment 30 of reinforcement determines the axial yield or extensibility of the bladder 10 which is limited for purposes of this specification to that extensibility which assures adequate support across the full width of the tire when it is expanded to the circumference required for completion and molding the liner 31 prevents air from entering into the reinforcement when the bladder is pressurized for shaping the tire carcass generally the reinforcing material 30 will 34 straighten out 34 or flatten to provide approximately 1 2 inch of axial dimension per convolution so that the four convolutions 26 provide about 2 inches of additional axial dimension and the two end portions 35 provide about one inch of additional axial dimension since the initial width of the tire carcass exceeds the width of the bladder this expansion or stretching of the bladder is necessary to properly shape the tire bands of parallel 1 u00d7 5 u00d7 0 006 inch steel cords 32 are situated in the thick portions 28 29 and 37 with the cords 32 having their lengths parallel to the bladder axis and they are spaced from and exterior to the first segment 30 of reinforcing material the cords 32 add rigidity to the bladder 10 and govern axial extensibility in the area in which tney are situated to a low value since they are less extensible than the reinforcing material 30 a second segment 41 of reinforcing material is situated adjacent.