Heavy duty tire

A heavy duty tire comprising a carcass extending from a tread portion to a bead core of a bead portion through a sidewall portion, and a belt layer having a first belt ply arranged inside the tread portion and outside the carcass and a second belt ply outside the first belt ply, wherein

• said second belt ply is curved in a form of projection of a single arc having a radius of curvature Rb of 450 to 700 mm,
• when a tread thickness between an outline of a tread surface and said second belt ply is defined as T, a tread thickness minimum position Qt in which said tread thickness becomes a minimum value Tmin is provided in a region Y which is away from a tire equator C by a distance of 0.5 to 0.7 times of a tread grounding half width, a ratio Tmin/Tc between the minimum value Tmin and a tread thickness Tc at the position of said tire equator C is 0.92 to 0.97, and a ratio Tb/Tc between a tread thickness Tb at a position of an outer end of said second belt ply and said tread thickness Tc is 0.95 to 1.10,
• when a tread thickness between said outline of the tread surface and said carcass is defined as K, a tread thickness minimum position Qk in which said tread thickness K becomes a minimum value Kmin is provided in said region Y, a ratio Kmin/Kc between the minimum value Kmin and a tread thickness Kc at a position of said tire equator C is 0.97 to 0.998, and a ratio Kb/Kc between the tread thickness Kb at a position of the outer end of said second belt ply and said tread thickness Kc is 1.2 to 1.5.