Patent ID: 8091597
Filing Date: 2012-01-10
Classification: B60C,Y10S

Abstract:
1. A heavy-duty tire provided in a tread portion with an inner circumferential groove extending in the circumferential direction on each side of the tire equator, and an outer circumferential groove disposed on the axially outer side thereof, thereby forming a middle land zone between the inner and outer circumferential grooves, wherein said middle land zone is formed as a row of middle blocks in which a number of middle blocks sectionalized by lateral grooves intersecting the middle land zone are arranged at certain intervals in the circumferential direction; a tread surface of the middle block is enclosed with said inner circumferential block edge comprises the inner circumferential block edge extends outward in the tire axial direction from said first-side and second-side protruding points to said denting point; both of the circumferential distance Lia from said first-side circumferential end to said first-side protruding point and the circumferential distance Lib from said second-side circumferential end to said second-side protruding point are in a range of from 5 to 15% of the circumferential length Li of said inner circumferential block edge; said outer circumferential block edge comprises the outer circumferential block edge extends inward in the tire axial direction from said first-side and second-side protruding points to said denting point; both of the circumferential distance Loa from said first-side circumferential end to said first-side protruding point and the circumferential distance Lob from said second-side circumferential end to said second-side protruding point are in a range of from 5 to 15% of the circumferential length Lo of said outer circumferential block edge; said inner circumferential block edge is made up of said outer circumferential block edge is made up of the inclination angle αa of said first-side axial block edge with respect to the tire axial direction is in a range of from 10 to 20 degrees; said middle block is provided with a single middle sipe whose both ends are terminated within the middle block; and the middle sipe is made up of