| 摘要 |
<p>An up carcass layer (12) having organic fibers is wound around a bead core (16) from inside to outside; a down carcass layer (14) having organic fibers is wound around the bead core (16) from outside to inside so as to cover the wound portion of the up carcass layer (12). The up carcass layer (12) has a rectilinear configuration (at 25) radially from a position where the up carcass layer (12) is wound around the bead core (16), in a cross section taken radially of the axis of rotation of the tire, in a static state in which the inflation pressure of the tire corresponds to 5% or less of its nominal value. The percentage, RH,of a radial height (HL) of the up carcass layer (12) from the tire rim to a rectilinear terminating portion thereof with respect to the height, Hs, of the tire section is set to a range Rw/4 + 10 </= RH </= Rw/4 + 20, where Rw is the percentage ratio of the nominal width, WR, of the tire rim to the nominal width, WT, of the tire. Hence, the tension of a portion of the carcass in the vicinity of the bead core becomes high, so that pressure strain is reduced.</p> |
