| 摘要 |
PURPOSE:To contrive to improve the straight running property and durability at high speed running by a structure wherein carcass cord layers are laminated in two layers or an upper and a lower layers and the reinforcement cords of the respective layers are arranged so as to make the mean value of and difference between the respective angles of said reinforcement cords toward the peripheral direction of the tyre specified angles. CONSTITUTION:If the mean value beta of the angle alpha1 of the reinforcement cord of a lower carcass cord layer 4d and the angle alpha2 of the reinforcement cord of a upper carcass cord layer 4u is smaller than 96 deg., plys-tear is not made better than its conventional level, while if the value beta is larger than 108 deg., the plys-tear is improved further, however the drive comfortability and load durability get worse than ever. If the difference alpha2-alpha1 between the angles alpha2 and alpha1 is smaller than 10 deg. even under the condition that the value beta lies in the range of 96-108 deg., the plys-tear does not be improved as compared with the conventional plys-tear, while, if alpha2-alpha1 is larger than 40 deg., the plys-tear is improved, however the load durability gets worse than ever. Consequently, the difference alpha2-alpha1 must lie in the range of 10-40 deg.. |
