| 摘要 |
PURPOSE:To reduce pattern noise by determining specially the ratio of the discrepancy-length between subgrooves to the repeated length in the direction of a pattern circumference by said subgroove in the pneumatic tyre with block like tread pattern formed by main grooves and subgrooves. CONSTITUTION:A plurality of linerar main grooves 1, subgrooves 2 connecting said main grooves 1 and blocks 4 are made on a tyre. Minimum discrepancy- amount (b) is formed between the subgrooves opening into the same main groove 1. The ratio (b)/(a) of said discrepancy-amount (b) to the repeated length (a) of said subgrooves 2 in the circumferential direction of the tread pattern is determined to be in the range of 0.4-0.5. Consequently, piton noise may be reduced and pattern noise is lowered, thereby improving the properties of safety and dwelling for a vehicle. |
