Patent ID: 8371351

Claim:
A pneumatic radial tire comprising: a pair of annular bead portions; a tread portion located at an external side, in a tire-radial direction, of the pair of bead portions, and including a tread surface portion including a tire equator line that is a center line in tire-width directions; a pair of sidewall portions each connecting one of both end portions in the tire-width directions of the tread portion and an outward end in the tire-radial direction of the corresponding one of the bead portions; and a carcass layer extending continuously across and through the bead portions, the sidewall portions, and the tread portion, the carcass layer being configured to form a framework of the tire, wherein, in a section taken in the tire-width directions, a first rubber gauge on a vehicle-fitted outer side is thicker than a first rubber gauge on a vehicle-fitted inner side, the first rubber gauge being defined as a thickness measured from a tire's external surface to the carcass layer and measured at each of the both tire-width-direction end portions of the tread portion, and a second rubber gauge on the vehicle-fitted outer side has a smaller thickness than a second rubber gauge on the vehicle-fitted inner side does, the second rubber gauge being defined as a thickness measured from the tire's external surface to the carcass layer in the tire-width direction and measured at each of both widest portions of the sidewall portion, the widest portions being the portions protruding most externally in the tire-width directions.