Heavy duty tire

A heavy duty tire having a nominal aspect ratio of 65% or less and comprising a tread that comes into contact with a road surface and a band that is located inward of the tread in a radial direction and that includes a spirally wound band cord, wherein

• at least three circumferential grooves are formed on the tread, whereby at least four land portions are formed in the tread,
• among the at least three circumferential grooves, a circumferential groove located on each outer side in an axial direction is a shoulder circumferential groove,
• a land portion located outward of the shoulder circumferential groove in the axial direction is a shoulder land portion,
• the band includes a full band having ends opposed to each other across an equator plane, and a pair of edge bands located outward of the ends of the full band in the radial direction,
• a narrow groove is formed on the shoulder land portion so as to extend in a circumferential direction,
• the narrow groove includes an inner groove wall that is located on an equator plane side and that connects a groove opening and a groove bottom of the narrow groove, and an outer groove wall that is located outward of the inner groove wall in the axial direction and that connects the groove opening and the groove bottom of the narrow groove,
• the inner groove wall includes an inner recess portion that is recessed inward in the axial direction, on the groove bottom side,
• the outer groove wall includes an outer recess portion that is recessed outward in the axial direction, on the groove bottom side,
• the narrow groove includes an expansion portion defined by the inner recess portion and the outer recess portion,
• a ratio of a groove width at the groove opening of the narrow groove to a maximum width of the expansion portion is not greater than 1.0,
• the narrow groove includes a tubular portion that connects the groove opening and the expansion portion and that extends straight, and
• the groove bottom is located outward of a center line of the tubular portion in the axial direction, and a height in the radial direction of the inner recess portion is lower than a height in the radial direction of the outer recess portion.