Patent ID: 6123129
Filing Date: 2000-09-26
Classification: B60C

Abstract:
A pneumatic radial tire for passenger car having a directional tread pattern defined by a circumferential center groove continuously extending in parallel to a circumferential direction of the tire or substantially in parallel thereto, a plurality of directional slant grooves disposed at intervals in the circumferential direction of the tire and extending obliquely with respect to the circumferential direction of the tire, and a plurality of blocks formed at intervals in both circumferential and axial directions of the tire and having an acute corner portion, provided that a rotating direction of the tire in the mounting onto a vehicle is specified so as to firstly contact a portion of the directional slant groove extending toward a side of an equatorial plane of the tire with ground and lately contact a portion thereof far away from the equatorial plane with ground, in which (1) these blocks form a pair of central block rows arranged on both sides of the equatorial plane in a central zone of the tread and a pair of side block rows arranged at an outside of each of the central block rows in the axial direction of the tire; (2) a surface of an acute corner portion of a block constituting the central block row, which is located outward in the axial direction of the tire, and a surface of an acute corner portion of a block constituting the side block row, which is located inward in the axial direction of the tire, are chamfered so as to gradually shallow from a tip of the corner portion toward a width-widening part thereof and to make a chamfering depth of the tip shallower than a depth of the directional slant groove; and (3) an acute corner portion of a block constituting the central block row located outward in the axial direction of the tire and an acute corner portion of a block constituting the side block row located inward in the axial direction of the tire are connected to each other at their chamfered shallowest tips to from a false dividing groove between the central block row and the side block row.