A pneumatic tire for heavy duty having an aspect ratio of 65% or less includes a carcass and a belt layer. A tread portion includes circumferential grooves. The circumferential grooves include a pair of shoulder circumferential grooves and a crown circumferential groove. The crown circumferential groove 11 is a narrow groove and each of the shoulder circumferential grooves is a wide groove. The belt layer includes metal belt cords inclined with respect to a tire circumferential direction. The belt layer has outer ends each positioned outside a respective one of the shoulder circumferential grooves in a tire axial direction. A belt half width is 55% or more and 85% or less of a carcass half width.

A pneumatic radial tire for aircraft in the present disclosure includes a bead core formed by a pair of cable beads embedded in a respective pair of bead portions, a pair of bead fillers respectively arranged outward in a tire radial direction from the pair of bead cores, and a carcass formed by two or more carcass plies that extend toroidally between the pair of bead cores. In a tire widthwise cross-sectional view, an end of a carcass ply, among the two or more carcass plies, closest to the bead filler in a region inward in a tire width direction from the bead filler is located in a region corresponding to 45° to 90° inward in the tire width direction when 0° is defined as outward in the tire radial direction from a center of the bead core.

A pneumatic radial tire for aircraft in the present disclosure includes a bead core formed by a pair of cable beads embedded in a respective pair of bead portions, a pair of bead fillers respectively arranged outward in a tire radial direction from the pair of bead cores, and a carcass formed by two or more carcass plies that extend toroidally between the pair of bead cores. In a tire widthwise cross-sectional view, an end of a carcass ply, among the two or more carcass plies, closest to the bead filler in a region inward in a tire width direction from the bead filler is located in a region corresponding to 45° to 90° inward in the tire width direction when 0° is defined as outward in the tire radial direction from a center of the bead core.

In a cross-section of a pneumatic tire, a contour of the bead core is a polygon formed by tangent lines of circumferential portions of a bead wire, the contour includes a vertex with an acute angle and a bottom side opposite the vertex, the carcass layer is folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from an outer end of the bead core extends in the radial direction, and a distance in the radial direction between a center of an arc profile of a tire outer surface and a straight line extending in the lateral direction through the vertex is within 20% of a radius r of the arc, and a distance in the lateral direction between the center of the arc and a straight line extending in the radial direction through the vertex is within 2r±0.4r.

In a cross-section of a pneumatic tire, a contour of the bead core is a polygon formed by tangent lines of circumferential portions of a bead wire, the contour includes a vertex with an acute angle and a bottom side opposite the vertex, the carcass layer is folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from an outer end of the bead core extends in the radial direction, and a distance in the radial direction between a center of an arc profile of a tire outer surface and a straight line extending in the lateral direction through the vertex is within 20% of a radius r of the arc, and a distance in the lateral direction between the center of the arc and a straight line extending in the radial direction through the vertex is within 2r±0.4r.

OD is defined by an outer diameter of the pneumatic tire, RW is defined by a rim width of a rim wheel assembled to the pneumatic tire, SW is defined by a tire width of the pneumatic tire, and RD is defined by a rim diameter of the pneumatic tire, the OD is 350 mm or more and 600 mm or less, the relation of 0.78≤RW/SW≤0.99; and the relation of 0.56≤RD/OD≤0.75 are satisfied.

The pneumatic tire has an annular carcass formed by using a carcass treat in which a carcass cord arranged along the tire width direction is covered with a rubber material, and a belt layer formed by arranging a resin covered cord outside the tire radial direction of the carcass and covered with a resin material along the tire circumferential direction. The treat strength of the carcass treat along the tire width direction is 10 kN/25 mm or more.

The pneumatic tire has an annular carcass formed by using a carcass treat in which a carcass cord arranged along the tire width direction is covered with a rubber material, and a belt layer formed by arranging a resin covered cord outside the tire radial direction of the carcass and covered with a resin material along the tire circumferential direction. The treat strength of the carcass treat along the tire width direction is 10 kN/25 mm or more.

Provided is a pneumatic radial tire for an aircraft including a bead core, a radial carcass and a stiffener, the radial carcass including one or more turn-up plies and one or more down plies, wherein in tire axial direction cross-sectional view, when an intersection point of a virtual circle with a ply closest to a tire axial direction inner side of the stiffener among the plies intersecting with the virtual circle having a radius that is twice as large as a diameter D of the bead core from a center O of the bead core is a point A, an intersection point of the virtual circle with a ply closest to a tire axial direction outer side of the stiffener is a point B, and a midpoint between the point A and the point B is a reference point C, then a line segment OC connecting the center O of the bead core to the reference point C has an inclination angle θ of 17° or less to a tire radial direction line passing the center O of the bead core on the tire axial direction outer side.

Provided is a pneumatic tire enabling improvement of side cut resistance and suppression of increase in mass. A pneumatic tire 1 includes: a tread portion 2; a pair of sidewall portions 3; a pair of bead portions 4 having respective bead cores 5 embedded therein; and a toroidal carcass 6 disposed between the pair of bead portions 4. The carcass 6 includes a first ply 11 extending on and between the pair of bead portions 4, and a second ply 12 disposed, in the tread portion 2, outward of the first ply 11 in a tire radial direction and extending on and between the pair of bead portions 4. The first ply 11 is formed as a layer of first cords. The second ply 12 is formed as a layer of second cords. A thickness of each second cord is 1.1 to 2.0 times a thickness of each first cord.