| 摘要 |
A heavy duty radial tyre having an aspect ratio (H/TW) being in the range of 0.5 to 0.7, said tyre comprising a tread portion (2) with a curved tread profile (2A), a pair of axially spaced bead portions (4) each with a bead core (5) disposed therein, a carcass (6) comprising at least one carcass ply extending between the bead portions (4) and turned up around the bead cores (5), characterised by a belt (7) comprising a plurality of belt plies (11-14), including a widest ply (12), disposed radially outside the carcass (6) and inside the tread portion (2), said widest belt ply (12) having a curved radially inner surface, the tread profile (2A) being made of an arc having a centre on the tyre equator (CO), said arc having a radius of curvature TR being 1.85 to 2.35 times the maximum tyre cross sectional width TW, the width BMW of said widest belt ply (12) being 0.74 to 0.8 times the maximum tyre cross sectional width TW, each axially outer portion (12B) of said radially inner surface of the widest ply (12) having a single radius of curvature BR of 2.25 to 2.8 times the maximum tyre cross sectional width TW, each said axially outer portion (12B) extending from each ply edge thereof to a middle point (A) between said ply edge and the tyre equator (CO), and each said axially outer portion (12B) being smoothly connected to an axially inner portion (12A) of said radially inner surface, said axially inner portion (12A) extending from the middle point (A) on one side of the tyre equator to that on the other side of the tyre equator (CO). <IMAGE>
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