Patent ID: 7934526

Claim:
An aircraft pneumatic tire comprising: bead cores provided in a left-and-right pair of beads; a carcass extending from the crown of the tire through both sidewalls of the tire to both beads, wound around the bead cores, and thereby fixed to the beads; a top tread disposed on the outside of the carcass in the radial direction of the tire; and at least one crown protective layer disposed between the carcass and the top tread, wherein at least part of the top tread in the width direction of the tire has a two-layer structure consisting of a base tread layer and a cap tread layer stacked in the radial outward direction in this order, at least one circumferential groove is provided in the surface of the top tread, and the base tread layer and the cap tread layer satisfy the relationships expressed by the following formulas (1) and (2): 1.05< M (50) b / M (50) c ≦1.30 (1) 1.04< R b / R c ≦1.20 (2) (wherein M(50) b and M(50) c denote 50% moduli of a base tread rubber and a cap tread rubber, respectively, and R b and R c denote the resiliences of the base tread rubber and the cap tread rubber, respectively); and wherein the cap tread rubber has a 50% modulus M(50) c of 1.5 to 1.7 MPa, a 100% modulus M(100), of 3.0 to 3.3 MPa, resilience R c of 50 to 52, and a dynamic storage modulus E′ of 0.9 to 1.2 MPa.