A pneumatic tire comprises an asymmetric tread pattern with a designated install direction to a vehicle having an outboard tread edges, the tread pattern having an outboard tread portion between the outboard tread edge and a tire equator and provided with an outer main groove, the outer main groove having a cross section comprising a bottom with a depth of 5.5 to 6.5 mm, and axially inner and outer groove walls each extending from the bottom to a tread contact surface, respectively, at least one of groove walls having a stepwise shape comprising a radially inner portion extending from the bottom with a height of 2.0 to 4.0 mm, an axially extending stepped portion extending from the radially inner portion with a length of 0.75 to 1.25 mm, and a radially outer portion between the stepped portion and the tread contact surface.