| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of ensuring on-ice performance at a brand-new time by forming narrow grooves on the top of a contact surface of a land portion partitioned on a tread portion, preventing polygonal wear when exhibiting intrinsic properties of tread rubber promptly by wearing the narrow groove early. SOLUTION: The pneumatic tire having: tread portion 1 where a plurality of land portions 4 arranged in the circumferential direction of the tire are partitioned; pitches P1 to P3 lying on these land portions 4 in the circumferential direction of the tire where periodic variations are provided, is formed with a plurality of the narrow grooves 5 on the contact surfaces of the land portions 4. The smaller the pitches of the land portions 4 are, in comparison with the land portions 4 having the larger pitches, the larger the width Pw of the narrow grooves 5 are to be made. The smaller the pitches of the land portions 4 are, in comparison with the land portions 4 having the larger pitches, the smaller the spaces Pp of the narrow grooves 5 are to be made. The smaller the pitches of the land portions 4 are, in comparison with the land portions 4 having the large pitches, the deeper the depth Pd of the narrow grooves 5 are to be made. COPYRIGHT: (C)2007,JPO&INPIT
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