| 摘要 |
<p>PURPOSE:To reduce noise by using polyvinylalcohol fibers having specific twist coefficient and strength for organic fiber cords forming a belt reinforced layer, and by specifying the relationship between the height of fold-back of a carcass ply and the tensile stress of bead filler rubber. CONSTITUTION:An organic fiber cord layer forming a belt reinforced layer is formed of cords made of high-strength and high-elasticity polyvinylalcohol fibers which are twisted. Further, the twist coefficient NT obtained from the formula I of organic fiber cords extracted from the tire is set to be0.19< NT, 0.55, the strength S (g/d) thereof is set to be S y15,5 IZNTl Further, The height H of fold-back of the bead section 3 of a carcass ply 1 and the tensile stress M(kg/cm<2>) of bead filler rubber 2 during 50 % elongation at a room temperature are specified so as to satisfy the following relationship: H>-2.5M + 125. With this arrangement, it is possible to reduce noise without deteriorating the maneuvering stability and braking characteristic on a wet road surface.</p> |
