| 摘要 |
<p>A tread (14) of a heavy-duty pneumatic radial tire (10) comprises a pair of upper and lower rubber layers (20, 18) having mutually differnt moduli of elasticity, and a small-width groove (24) formed in the upper rubber layer (20) in such manner as to be substantially continuous in the circumferential direction of the tire. The dimension between a boundary surface (X) bordering the two rubber layers and the bottom (26) of the groove (24) is set to be 1 mm or more. Accordingly, there may be prevented the occurrence of cracks due to a deforming stress acting in the groove bottom occurring when the tire rolls or rides on a kerbstone.</p> |
