| 摘要 |
<p>A heavy duty radial tyre comprising a belt (11) having a 1st ply (11), a 2nd ply (12) and a 3rd ply (13) disposed radially outside a carcass (6) in the tread portion (2), each belt ply being of parallel cords laid at an angle of from 15 to 30 degrees with respect to the tyre equator, and the ply strength (S1) of the radially innermost 1st ply (11) is in the range of from 0.8 to 1.5 times, more preferably 1.0 to 1.2 times the sum (S2+S3) of the ply strength (S2) of the 2nd belt ply (12) and the ply strength (S3) of the 3rd belt ply (13). The cord angles a of the 1st, 2nd and 3rd belt plies may be substantially the same absolute values, and the cord inclination ( alpha 1) of the 1st ply (11) may be reversed to the cord inclinations ( alpha 2 alpha 3) of the 2nd and 3rd belt plies (12,13). <IMAGE></p> |
