Pneumatic radial tires

摘要

A pneumatic radial tire comprises a tread provided with a plurality of circumferential grooves extending in a circumferential direction of the tire, and plural rows of land portions defined between axially adjacent circumferential grooves and between each of edges of the tread and the adjacent main circumferential groove. That groove wall of at least the circumferential groove located nearest to at least one of the tread edges on a treading surface of the tread which is positioned on a side of the one of the tread edges is inclined to gradually increase a width of the groove toward the surface of the tread from a location spaced by 10-70% of a depth of the circumferential groove radially outwardly from a bottom thereof. The width of an opening of the circumferential groove to the surface of the tread is in a range of 3-18 mm.