Patent ID: 8025084
Filing Date: 2011-09-27
Classification: B60C,Y10T

Abstract:
1. A pneumatic radial tire which has a nominal section width of not less than 255 mm, and an outer diameter of not less than 720 mm, and in which at least one carcass layer is constructed between paired right and left bead cores with the two end portions of the carcass layer being folded back from the inside to the outside of the tire around the respective bead cores in a way that their corresponding bead fillers are enclosed in the two folded end portions of the carcass layer, and in which a belt layer is arranged on the circumference of the carcass layer, wherein: the length (L the carcass layer is formed of organic fiber cords made of at least one type of organic fiber which has an expansion ratio of 1% to 5% when a load of 2.0 cN/dtex is applied to the organic fiber, and a sheet-shaped rubber reinforcement layer with a thickness of 0.5 mm to 2 mm, whose rubber has a larger rubber hardness than that of a sidewall section, is interposed between the carcass layer and the sidewall section on each side of the tire, wherein the pneumatic radial tire includes two carcass layers, and on each side of the tire, an end portion of the folded part of one carcass layer is inserted between the carcass layers and the belt layers, and an end portion of the folded part of the other carcass layer stays in any one of a bead section and the sidewall section.