| abstract |
A radial tire (10) has a pair of bead portions (12); a carcass (14) which is toroidal and extends across the bead portions; a tread portion (16) positioned at a crown portion of the carcass; sidewall portions (18) of the carcass; and at least one belt reinforcing layer (22) disposed at the entire tread portion and/or at both end portions of the tread portion at an outer peripheral side of at least two belt layers (20) which are disposed at an inner side of the tread portion, the belt reinforcing layers being formed by narrow, rubber-coated strips, which include a plurality of fiber cords, being wound endlessly in spirals so that the fiber cords are substantially parallel in a circumferential direction of the tire. According to the invention, the belt reinforcing layer cords comprise organic fiber cords, the elongation of the organic fiber cords under 1.4 g/d load at 50 ± 5°C being less than or equal to 2.7%, and the elongation under 0.7 g/d load at 170 ± 5°C being 1.5 to 6.0%. Such a radial tire has a good balance of low rolling resistance, durability at high speeds and handling stability. Further, road noise is greatly reduced in a range extending from low frequencies to high frequencies. |