Patent ID: 8225834

Claim:
A pneumatic tire for heavy load comprising: a circumferentially-formed groove running in a tire circumferential direction on a surface of a tread part; at least two crossing belts arranged at an angle not less than 10 degrees and not more than 30 degrees with respect to the tire circumferential direction; and at least one circumferential reinforcement layer arranged at an angle not less than zero degrees and not more than five degrees with respect to the tire circumferential direction provided at an outer side of a carcass layer in the tire radial direction; wherein when a pneumatic pressure equivalent to a normal inner pressure is applied to the tire with reference to a case where a pneumatic pressure equivalent to an inner pressure of 100 kPa is applied, a radius growth in a tire radial direction at a crown center of the tread part and in the circumferentially-formed groove located at a most lateral side in a tire width direction is less than 0.3%, wherein a summation ΣLi [kN] of a circumferential force of the crossing belts and the circumferential reinforcement layer with respect to a normal load W [kN] is set within a range expressed by 3.00≦ΣLi/W≦4.20, wherein when a straight line drawn from a position of a rim height FH in the tire width direction is treated as an X axis and a straight line drawn in the tire radial direction through the crown center is treated as a Y axis, a nominal dimension S for an aspect ratio, a distance USH in the Y-axis direction from a maximum width position T of a carcass layer in the tire width direction to an inflection point Q of the carcass layer, a distance HB from the X axis to a top R of the carcass layer at the crown center, a distance WE from the Y axis to the maximum width position T of the carcass layer in the tire width direction, and a distance WF from the Y axis to the inflection point Q of the carcass layer have a relationship expressed by 0.48 ≦USH/HB≦ 0.52, a relationship expressed by 5.52 S 2 ×10 −5 −2.407 S× 10 −2 +2.29 ≦WE/HB≦ 5.52 S 2 ×2.407 S× 10 −2 +2.39, and a relationships expressed by −1.1312 S 2 ×10 4 +5.822 S× 10 −3 +0.62 ≦WF/WE≦− 1.1312 S 2 ×10 −4 +5.822 S× 10 −3 +0.68.