| 摘要 |
<p>A heavy duty radial tyre comprises: a carcass ply (6) turned up around a bead core (5) in each bead portion (4) from the inside to outside of the tyre so as to form a pair of turnup portions (6B) and a main portion (6A) therebetween; a rubber bead apex (8) disposed between each of the turnup portions and the main portion, each of the turnup portions extending radially outwardly beyond a radially outer end (8E) of the bead apex to adjoin the main portion (6A); a chafer rubber (9) disposed along at least an axially outer surface of each of the bead portions so as to define at least a flange-contacting part (S3) for contacting with a flange (J1) of a wheel rim (J); the height (L1) of the radially outer end (8E)of the bead apex (8) being in the range of from 7 to 35 % of the height (H) of the carcass at the tyre equator (C) and being less than the height (L3) of the radially outer end of the chafer rubber (9); and the flange-contacting part (S3) being devoid of a concave profile. When the carcass ply is made of steel cords whose sectional area is in the range of from 0.10 to 0.25 sq.mm, a carcass reinforcing layer (19) is disposed along the carcass so as to extend at least between the maximum tyre width points (P1) and the edges (7E) of a belt disposed radially outside the carcass in the tread portion. <IMAGE></p> |
