| 摘要 |
PURPOSE:To improve controllability and rectilinear derivability in a pneumatic radial tire having a directional tread pattern by forming quasi main grooves on both sides of a main groove in the same direction as inclined sub-grooves at a predetermined inclination and setting a circumferential projected length of the tire larger than a circumferential ground contacting length of the ground contacting surface of the tire under the regular condition. CONSTITUTION:A directional pattern is formed of a straight main groove 1 in the circumferential direction of a tire and sub-grooves 2 inclined to designated rotational direction R of the tire in the opposite directions R toward ground contacting ends E. At least one quasi main groove 3 is formed respectively no both sides of the main groove 1 to be inclined in the same direction as the sub-groove by 3-30 deg. of an average inclination alpha to the circumferential direction of the tire. Also, the circumferential projected length L1 of the tire is set larger than the circumferential ground contacting length L2 of the ground contacting surface of the tire under the regular internal pressure and load. |
