| 摘要 |
A radial tyre for a motor cycle comprising a carcass (6) having a main portion (6a) extending from a tread (2) through side walls (3) to a bead core (5) in each of two beads (4) and a pair of turned up portions (6b) turned up one around each bead core (5), and composed of at least one carcass ply of cords laid at an angle of 70 to 90 degrees to the tyre equator, a belt layer (7) disposed radially outside the carcass (6) and in the tread (2), and composed of at least one belt ply of cords (11) with modulus of elasticity of 600 kg/mm<2> or more wound spirally nearly parallel to the tyre equator, and a bead apex (9) having a substantially triangular section disposed on the bead core (5) between the main part and turned up part (6b) of the carcass, said tread (2) having a width (TW) between tread edges (E1,E2) in the axial direction which is larger than the maximum width of the tyre in the axial direction at the side walls (3) and the tread surface being an approximately arc shape in the tyre meridian section, characterised in that the bead apex (9) of a soft apex part SA composed of a soft rubber composition with a JISA hardness of 50 to 60 degrees extending radially outwardly from a bottom surface adjacent to the bead core (5) and a hard apex part HA composed of a hard rubber composition with JISA hardness of 70 to 95 degrees extending radially outwardly from the soft apex part SA, a height hl of the radially upper end P1 of the soft apex part SA from a bead base is 0.20 to 0.40 times a height h0 of the tread end from the bead base (BL), and a height h2 of the radially upper end P2 of the hard apex part HA from the bead base (BL) is 0.50 to 1.25 times the height h0 of the tread end. <IMAGE> |
