Vehicle tire including main grooves and lug grooves

Abstract

A vehicle tire comprises circumferentially extending straight main grooves including a central main groove on the tire equator and an axially outer main groove on each side thereof, first lug grooves extending from the axially outer main grooves towards the central main groove but not reached thereto, each of the first lug grooves comprising a first curved portion, a second curved portion and a straight portion arranged in this order from the outer main groove towards the central main groove, wherein a width of the first curved portion is in the range of from 60 to 80% of the width of the outer main groove, a width of the second curved portion is not less than 25% but less than 60% of the width of the outer main groove, and a width of the straight portion is not more than 25% of the width of the outer main groove, an inclination angle of each first lug groove with respect to the tire circumferential direction being in the range of from 30 to 50 degrees at the outer main groove, and gradually decreasing therefrom in the first and second curved portions, and being substantially zero in the straight portion, a depth of each first lug groove being smaller in the straight portion than the first curved portion. Corners formed between the circumferential grooves and lateral grooves are rounded by a conical face of which radius of curvature gradually increases towards the radially outside of the tire.