| 摘要 |
A pneumatic radial tire, particularly for a construction vehicle, has a carcass ply arranged toroidally between a pair of bead cores, containing rubber coated steel cords disposed radially therein, being turned up around each bead core from the inside to the outside of the tire and the turn-up portion of which around each bead core extends to around +E,fra 1/2+EE height of the tire height H. When the radical length of an overlapping portion of the turn-up portion of the carcass ply and the main carcass ply is h1 and the thickness of the overlapping portion is w1 within a range of +/-0.1 H having half height H/2 of the tire height H as the center, the radial length h and the thickness w of a reinforcing rubber material arranged between the turn-up portion of the carcass ply and the main ply satisfy the following formulae (1) 0.2w1</=w</=1.0w1, and (2) 0.5h1</=h</=1.0h1, and said reinforcing rubber material satisfies the following conditions (3) 100 parts by weight of rubber includes 10-80 parts by weight of a cis-1,4 polybutadiene, and (4) a modulus of elasticity M is 60 kgf/cm2</=M</=100 kgf/cm2 at 300% elongation and a rebound resilience coefficient R is 0.4<R<0.7.
|
