Pneumatic tire including three asymmetrically arranged main grooves

Abstract

A pneumatic tire includes a tread portion provided with three straight main grooves extending continuously in the tire circumferential direction. The three main grooves are arranged asymmetrically about the tire equator such that an exterior main groove, which is one of the main grooves, is disposed in an exterior half, which is one half of the tread portion on one side of the tire equator. An axially inner main groove and an axially outer main groove, which are the remaining two main grooves, are disposed in an interior half which is the other half of the tread portion. Exterior oblique grooves are disposed axially outside the exterior main groove and inclined at an angle .theta. 1 of 45 to 70 degrees with respect to the circumferential direction of the tire. Interior oblique grooves are disposed axially outside the axially outer main groove and inclined reversely to the exterior oblique grooves at an angle .theta. 3 of 60 to 80 degrees with respect to the circumferential direction. Central oblique grooves are disposed between the exterior main groove and the axially inner main groove and inclined in the same direction as the exterior oblique grooves. Furthermore, between the exterior main groove and the axially inner main groove, the angle .theta. 2 of the central oblique grooves are in the range of 20 to 45 degrees with respect to the circumferential direction.