Pneumatic tire

A pneumatic tire comprising

• a tread portion having a designated install direction to a vehicle to define an inboard tread edge and an outboard tread edge,
• the tread portion provided with a plurality of circumferentially and continuously extending inboard shoulder main groove to be located in the most inboard, a circumferentially and continuously extending outboard shoulder main groove to be located in the most outboard and a circumferentially and continuously extending center main groove between the inboard shoulder main groove and the outboard shoulder groove, to form an outboard shoulder portion between the outboard shoulder main groove and an outboard tread edge, an inboard shoulder portion between the inboard shoulder main groove and an inboard tread edge, an inboard middle portion between the center main groove and the inboard shoulder main groove, and an outboard middle portion between the center main groove and the outboard shoulder main groove,
• each of said inboard middle portion and outboard middle portion forming a rib that is not provided with any groove having a groove width of not less than 2 mm but provided with only sipes having widths in a range of less than 2.0 mm,
• said sipes provided on the inboard middle portion including a full-opened sipe that has one end connected with the inboard shoulder main groove and the other end connected with the center main groove,
• said sipes provided on the outboard middle portion consisting of a plurality of outer semi-opened sipes and a plurality of inner semi-opened sipes, each said outer semi-opened sipe having one end connected with the outboard shoulder main groove and the other end terminating within the outboard middle portion, and each said inner semi-opened sipe having one end connected with the center main groove and the other end terminating within the outboard middle portion, wherein
• the number of said inner semi-opened sipes is smaller than the number of said outer semi-opened sipes.