| 摘要 |
PURPOSE:To restrain tread rubber from deforming at the starting time of grounding and at the time of detaching from the ground so as to effectively suppress pumping sound by having the step-out side inclination greater than the opposide- side inclination in each of the shoulder lateral grooves and having the step-in side inclination greater than the opposed inclination in each of center lateral grooves. CONSTITUTION:Both right center lateral grooves 3(M) which communicate a center longitudinal groove GC with a right longitudinal main groove G2 and left center lateral groove 3(N) communicating said groove GC with a left center longitudinal groove G1 are spaced at specific intervals in the circumferential direction of a tyre, thus the middle part of a tread is divided into blocks. The inclination theta1 at the step-in side E1 of the tread is made less than the inclination theta2 at the step-out side E2 thereof. The center lateral grooves 3(M) positioned at the shoulder-side of a vehicle have such walls that an inclination theta3 at the step-in side of the tread is greater than an inclination theta4 at the step-out side thereof. The deformation of tread rubber at the starting time of grounding and the time of detaching from the ground can then be restrained to a minimum, whereby suppressing pumping sound. |
