Patent ID: 7878228
Filing Date: 2011-02-01
Classification: B60C,Y10S

Abstract:
1. A heavy-duty tire comprising a tread portion, the tread portion provided with at least three circumferentially continuously extending ribs divided by at least two circumferential grooves extending straight in the tire circumferential direction, wherein, the ribs include a center rib of which widthwise center is substantially aligned with the tire equator, and a pair of middle ribs disposed one on each side of the center rib, the ribs having side edges adjacent to the circumferential grooves, each said side edge provided with edge sipes at intervals in the tire circumferential direction, each said edge sipe extending parallel with the tire axial direction from the adjacent circumferential groove and terminated in the rib, wherein each said edge sipe has: an axial length in a range of not less than 5% but not more than 15% of the axial width of the rib; a thickness in a range of not less than 0.3 mm but not more than 1.0 mm; and a depth in a range of not less than 50% but not more than 100% of the depth of the circumferential groove, and the total number of the edge sipes per tire is in a range of from 4 to 8 times the value of the tire diameter in millimeters, each said middle rib is provided with mid sipes arranged in the tire circumferential direction, wherein each of the mid sipes has two closed ends terminated within the middle rib and has only the center rib is provided with mid sipes arranged in the tire circumferential direction, wherein each of the mid sipes of the center rib has two closed ends terminated within the center rib and is composed of