Abstract: A pneumatic radial tire for use in heavy duty vehicles such as an airplane and so on comprises at least one carcass ply as a tire body reinforcement, at least two belt layers as a tread reinforcement, and a tread provided with a pair of main grooves extending circumferentially of the tread at a position ranging from the side end of the tread within 15.about.40% of tread ground contact width. In this tire, the tread is composed of a tread rubber satisfying a requirement that modulus at 100.degree. C. under 100% elongation of tread rubber constituting each side portion of the tread is lower by a range of 30.about.80% than that of tread rubber constituting a central portion of the tread.

Abstract: A reinforcing laminate for use in a carcass or a belt of a heavy duty pneumatic radial tire comprises plural reinforcing layers piled one upon the other, each containing cords substantially arranged in parallel to each other and covered with a coating rubber, wherein the cords of the adjoining reinforcing layers are arranged in parallel to each other and the pitch between the cords in one of the reinforcing layers is shifted by an approximately half pitch from that of the other reinforcing layer.

Abstract: Improvement of stability of dynamic performance of pneumatic tire tread composition, by adding at least one of some esters such as phosphoric acid ester, fatty acid ester in a definite ratio to the known composition comprising styrene-rich SBR added with a processing oil and carbon black respectively in higher ratio for improving dynamic performance.

Abstract: A mark indication is formed on the tire side wall by sticking partially vulcanized thin rubber sheets provided with mark indications on one side of said sheets along the circumferential direction of the green case at the outer surface corresponding to the side wall of the green case formed on a former and tightly adhering the rubber sheet integrally to the side wall through molding the green case into a toroidal form and vulcanizing said green case.

Abstract: A pneumatic tire for high speed running vehicles having an aspect ratio of 0.25 to 0.75 and a carcass composed of at least two plies each formed of a textile cord layer including parallel cords crossed with those of the other ply. The carcass satisfies the following conditions:(1) The cord has an initial modulus of at least 100 g/denier;(2) The cords are embedded in rubber having a modulus of elasticity at 300% elongation of 100 to 250 kg/cm.sup.2 ;(3) The cords are inclined at an angle of 20.degree. to 40.degree. with respect to the equatorial plane of the tire;(4) The cords have a gap ratio in each ply of 10 to 65% and a gap ratio between adjacent plies of 22 to 83%.