Patent ID: 8875759
Filing Date: 2014-11-04
Classification: B60C,Y10S

Abstract:
1. A heavy duty tire comprising a tread portion having tread edges defining a tread width TW, a pair of sidewall portions defining a cross sectional width SW of the tire, a pair of bead portions each with a bead core therein, a carcass extending between the bead portions through the tread portion and the sidewall portions, and a belt composed of a plurality of belt plies disposed radially outside the carcass in the tread portion, wherein the tread width TW between the tread edge is in a range of 0.78 to 0.87 times the cross sectional width SW of the tire, the tread portion is provided with four or five circumferential grooves each of which has a depth of from 15 to 20 mm and extends continuously in the tire circumferential direction so as to axially divide the tread portion into five or six rib portions, the five or six rib portions are a pair of shoulder rib portions extending along the tread edges and provided with shoulder lateral grooves, and three or four crown rib portions disposed between the shoulder rib portions and each provided with crown lateral grooves, said crown lateral grooves are arranged at intervals in the tire circumferential direction, and extend across the entire width of the crown rib portion, and the depth of the crown lateral grooves is in a range of from 9 to 30% of the depth of the circumferential grooves, said shoulder lateral grooves are arranged at intervals in the tire circumferential direction, and extend axially outwardly from an axially inner edge of the shoulder rib portion so as to terminate at an axial distance of from 78 to 88% of the axial width of the shoulder rib portion from said axially inner edge, and the depth of the shoulder lateral grooves is in a range of from 9 to 25% of the depth of the circumferential grooves, when measured at the groove center line, a circumferential distance between the axial inner end and the axial outer end of the shoulder lateral groove is in a range of from 10 to 30% of a circumferential pitch length between the circumferentially adjacent shoulder lateral grooves, and each of the crown lateral grooves is provided in the groove bottom with a sipe extending along the length of the crown lateral groove, but no sipe is formed in the bottoms of the shoulder lateral grooves.