To solve the problem that, since a spare tire is attached to a trunk of a vehicle or a vehicle body for long time, air pressure is lower than a specified air pressure in many cases, and separation is likely to occur from the vicinity of a turn-up tip section of a carcass, and especially in a case of a bias tire, shear strain increases between layers in which carcasses intersects, to cause failure from this position.

In the bias tire including at least one set of carcass layers composed of organic fibers which are arranged intersecting with angles of 20 to 50 degrees to a tire equatorial plane, at least one reinforcement layer in which a cord is buried is arranged between carcass layers, at a position in the vicinity of the turn-up tip section positioned at outermost side of a tire diameter direction and on an inner side in the tire diameter direction from the carcass with which the turn-up section comes into contact. Any angle between the cord in the reinforcement layer and the cord in an intersection carcass layer is made smaller than an intersection angle between the cords in the intersection carcass layer.