Solid golf ball

A solid golf ball comprising an elastic core and a resin cover of at least one layer enclosing the solid core, said cover being composed of a plurality of layers including inner and outer layers, the cover outer layer having a JIS-C hardness of up to 85, and the cover inner layer having a JIS-C hardness which is at least 55 and higher than that of the cover outer layer, said cover having a flexural rigidity of 78 MPa (800 kgf/cm2) to 196 MPa (2000 kgf/cm2),

• wherein said cover outer layer is formed of a composition based on the reaction product of the thermoplastic polyurethane elastomer with an isocyanate compound and the isocyanate compound is selected from a group of aromatic isocyanate compounds, hydrogenated products of aromatic isocyanate compounds, aliphatic isocyanates and alicyclic diisocyanates, and the isocyanate compound used is at least 0.2 part by weight and up to 5 parts by weight, per 100 parts by weight of the thermoplastic polyurethane elastomer, and
• wherein provided that the ball receives a spin rate S1 (rpm) in the dry state and a spin rate S2 (rpm) in the wet state when hit with a short iron having a loft of an 8-iron or greater, the percent spin retention given by (S2/S1)×100 is at least 47%.