A tire comprising: a tread portion having a predetermined orientation for mounting on a vehicle to define an outboard tread edge (To) to be located outwardly of the vehicle and an inboard tread edge (Ti) to be located inwardly of the vehicle upon being mounted to the vehicle; the tread portion being provided with one circumferentially extending crown main groove, one circumferentially extending outboard shoulder main groove, and one circumferentially extending inboard shoulder main groove to divide the tread portion into an outboard crown land portion, an inboard crown land portion, an outboard shoulder land portion and an inboard shoulder land portion; the tread portion having a four- rib structure with the inboard crown land portion disposed on a side of the inboard tread edge (Ti) with respect to the crown main groove, the outboard crown land portion disposed on a side of the outboard tread edge (To) with respect to the crown main groove, the inboard shoulder land portion disposed axially outside the inboard crown land portions on a side of the inboard tread edge (Ti) and the outboard shoulder land portion disposed axially outside the outboard crown land portions on a side of the outboard tread edge (To); the inboard shoulder land portion being provided with inboard shoulder lateral grooves connecting the inboard tread edge (Ti) and the inboard shoulder main groove; the outboard shoulder land portion being provided with outboard shoulder lateral grooves extending axially inwardly from the outboard tread edge (To) and terminating within the outboard shoulder land portion; and the outboard crown land portion being provided with outboard crown lateral grooves extending from the crown main groove and terminating within the outboard crown land portion, characterized in that the inboard crown land portion being provided with inboard crown lateral grooves extending from the inboard shoulder main groove and terminating within the inboard crown land portion, wherein each of the inboard crown land portion and the outboard crown land portion comprises a rib region on an outboard tread edge side (To), and the rib region extends continuously in a tire circumferential direction without being divided by any lateral grooves having widths equal to or more than 2 mm. a tread portion having a predetermined orientation for mounting on a vehicle to define an outboard tread edge (To) to be located outwardly of the vehicle and an inboard tread edge (Ti) to be located inwardly of the vehicle upon being mounted to the vehicle; the tread portion being provided with one circumferentially extending crown main groove, one circumferentially extending outboard shoulder main groove, and one circumferentially extending inboard shoulder main groove to divide the tread portion into an outboard crown land portion, an inboard crown land portion, an outboard shoulder land portion and an inboard shoulder land portion; the tread portion having a four- rib structure with the inboard crown land portion disposed on a side of the inboard tread edge (Ti) with respect to the crown main groove, the outboard crown land portion disposed on a side of the outboard tread edge (To) with respect to the crown main groove, the inboard shoulder land portion disposed axially outside the inboard crown land portions on a side of the inboard tread edge (Ti) and the outboard shoulder land portion disposed axially outside the outboard crown land portions on a side of the outboard tread edge (To); the inboard shoulder land portion being provided with inboard shoulder lateral grooves connecting the inboard tread edge (Ti) and the inboard shoulder main groove; the outboard shoulder land portion being provided with outboard shoulder lateral grooves extending axially inwardly from the outboard tread edge (To) and terminating within the outboard shoulder land portion; and the outboard crown land portion being provided with outboard crown lateral grooves extending from the crown main groove and terminating within the outboard crown land portion, characterized in that the inboard crown land portion being provided with inboard crown lateral grooves extending from the inboard shoulder main groove and terminating within the inboard crown land portion, wherein each of the inboard crown land portion and the outboard crown land portion comprises a rib region on an outboard tread edge side (To), and the rib region extends continuously in a tire circumferential direction without being divided by any lateral grooves having widths equal to or more than 2 mm.