| 摘要 |
PROBLEM TO BE SOLVED: To provide a tire using a cheap chafer rubber excellent in heat resistance by setting to a specific condition value or more a hardness at a high temperature and an elongation at the time of breakage after traveling as to the physical property of the chafer rubber used in a rubber chafer part the chafer rubber. SOLUTION: In order that the physical property of the chafer rubber used in a rubber chafer part can endure a severe usage condition where temperature reaches a high temperature of 150 deg.C, the hardness thereof at a high temperature is specified so that 100% modulus at 150 deg.C is 40kg/cm<2> and more. Furthermore, since the chafer rubber is hardened by traveling as well as by deterioration it may happen that the toe part may become defective when an elongation at the time of breakage after traveling comes to a certain value or less. Consequently, even when the modulus is heightened, it is required that the elongation (Eb) at the time of breakage after traveling is secured to be a certain value or more. Eb after again of 100 deg.C×24h in air is specified as 200% or more. As a consequence, it becomes possible to suppress burst trouble and toe defect in city buses or the like where the brake heat becomes high.
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