A heavy duty radial tire comprises a belt layer having first and third plies of cords arranged at an angle of 10 to 45.degree. relative to the tire equator, and a second ply of cords arranged at an angle of at most 5.degree. relative to the tire equator, the widths W1 and W3 of the first and third plies are at least 85% of a ground contact width Tw and the width W2 of the second ply is at least 70% of the width Tw and is smaller than the widths W1 and W3; and a pair of reinforcing rubber layers disposed between the first and third plies so as to extend axially outwardly from the axially outer ends of the second ply comprising an axially inner portion having E*1 of 8.0 to 14.0 MPa, and an axially outer portion having E*2 of 6.0 to 12.0 MPa smaller than E*1.