Abstract: An off-the-road heavy duty pneumatic radial tire comprises a carcass of radial structure and a belt superimposed about a crown portion of the carcass, wherein the carcass profile in a radial section at temporary self-posture state of mounting onto a rim has a concave form between two particular contact points with respect to a straight line in parallel to the rotational axis of the tire at both sides of the equator and main belt layers constituting the belt are arranged along the concave carcass profile between the above two contact points.

Abstract: An off-the-road heavy duty pneumatic radial tire is suitable to be used on irregular grounds or roads. The tire includes a carcass of radially arranged cords and a belt of a plurality of rubber coated steel cords. The belt comprises a main layer of first, second and third layers whose cords in adjacent layers are arranged inclined reversely to each other with respect to an equatorial plane of the tire and a protective layer laminated on the main layers. Cords of the protective layer are high elongation cords whose tensile breaking elongation is 1.4 to 3.0 times that of the cords of the main layer of the belt. The second layer is narrower than the adjacent first layer and much narrower than the adjacent third layer. The protective layer extends wider than the widest third layer. Edges of the protective layer are on extensions of a center line of a total thickness of the main layers.