Abstract: A pneumatic tire for a passenger car having a pair of bead portions, a toroidal carcass portion extending over both bead portions, at least two belt layers provided in a crown portion of the carcass, a tread portion positioned at an outer peripheral side of the belt layer, and side wall portions provided at the right and left sides of the tread portion, and which further includes a steel cord as a reinforcing material for reinforcing at least one layer of the carcass portion and the belt layer. The steel cord is formed by plying a plurality of filaments each having a strand diameter of 0.125 to 0.275 mm, and has an inflection point on an S—S curve. A reduction rate of a diameter of the steel cord under a load stress which is one third of breaking strength in comparison with a no load condition is equal to or more than 20%.

Abstract: There is disclosed a safety pneumatic tire comprising a tire shell which is equipped with a toroidal carcass extending over a pair of bead portions and also functioning as a reinforcing material for a side wall portion connected to the bead portions and further for a tread portion, and which has a side-reinforcing layer on the internal surface of the side-wall portion; a rim which hermetically seals and supports the bead portions of the tire shell; and closed cell-based elastic foam which is filled in the internal hollow portion encompassed by the tire shell and the rim, wherein the constructional material of the elastic foam is butyl rubber or halogenated butyl rubber. The above safety pneumatic tire is markedly improved in run-flat durability, can reconcile favorable riding comfort chacteristic with the run-flat durability, is minimized in adverse influence upon the tire performances such as rolling resistance, and enables the production of a lightweight pneumatic tire.

Abstract: A pneumatic tire comprises a carcass of at least one rubberized ply of a radial arrangement, a belt comprised of two or more cross cord layers, a pair of thick reinforcing strip rubbers located at an inner face side of the carcass and a bead filler rubber, in which the reinforcing strip rubber and bead filler rubber have specified JIS hardness and rebound resilience, hardness ratio and maximum gauge ratio.

Abstract: In a pneumatic tire for run-flat running comprising a stiffener rubber, viewing a cross-section of the tire-rim assembly inflated under an air pressure corresponding to 15% of a maximum air pressure of the tire, a top of the stiffener rubber is located inward from a specified line segment PA in a radial direction of the tire.

Abstract: A polyester copolymer having an aromatic amine incorporated in the main chain, which is excelent in thermal stability as well as dynamic property, and a process for the production of the polyester copolymer, whereby the existing installation of the prior art can be used as it is, thus resulting in lowering of the production cost, are provided. The polyester copolymer comprises an aromatic dicarboxylic acid, diol and at least one compound selected from the group consisting of aromatic compounds having amino group, represented by the following general formula (I),H.sub.2 N--X--COOR (I)wherein X is an aromatic ring-containing group and R is a hydrogen atom or a hydrocarbon group selected from the group consisting of alkyl groups and cycloalkyl groups.

Abstract: Nylon cords having a yarn strength of not less than 12 g/d are subjected to a stretch heating treatment under specified conditions before the dipping and then dipped in a dipping solution having a particular composition, whereby the strength and adhesion force of the resulting dipped cords are considerably improved for use in large size tires.