Heavy load pneumatic radial tire with cap tread rubber, base tread rubber, and reinforcing rubber layer

A heavy load pneumatic radial tire comprising:

• tread rubber that has a laminated structure of cap rubber and base rubber;
• and four or more belt layers that are disposed radially inward of the tread rubber, the four or more belt layers including a radially outermost belt layer and a widest-width belt layer among the belt layers, wherein:
• a radially outer side of a width direction side edge of the radially outermost belt layer is covered by a reinforcing rubber layer configured to terminate on a radially inner side of the tread rubber without reaching a tire equatorial plane, and
• a relative relation between reinforcing rubber constituting the reinforcing rubber layer and the base rubber in terms of a modulus of rebound elasticity (%) satisfies the following condition:
• reinforcing rubber<base rubber,
• wherein a width (w) of the reinforcing rubber layer is within the range of 15-25% of a width (W) of a tread surface,
• wherein the reinforcing rubber layer is configured to terminate along a width direction of the tire without reaching the tire outer side surface, and
• wherein a width direction outermost end of the reinforcing rubber layer farthest away from the tire equatorial plane is positioned inward of an outermost end of the widest-width belt layer among the belt layers in the width direction of the tire.