Thermoplastic polyester elastomer golf ball cores

1. A golf ball comprising:

a core comprising an inner core sphere, an intermediate core layer and an outer core layer, the inner core sphere comprising a thermoplastic polyester elastomer formed from a polytetramethylene glycol with a molecular weight greater than or equal to 1400 g/mol, the inner core sphere having a diameter ranging from 0.875 inch to 1.4 inches, the intermediate core layer composed of a highly neutralized ionomer and having a Shore D hardness less than 40, the outer core layer composed of a highly neutralized ionomer and having a Shore D hardness less than 45, wherein a thickness of the intermediate core layer is greater than a thickness of the outer core layer;

an inner mantle layer disposed over the core, the inner mantle layer comprising an ionomer material and having a Shore D hardness greater than 55;

an outer mantle layer disposed over the inner mantle layer, the outer mantle layer comprising an ionomer material and having a Shore D hardness greater than 60;

a cover layer disposed over the mantle layer, the cover layer comprising a thermoplastic polyurethane material and having a Shore A hardness less than 100;

wherein the golf ball has a diameter of at least 1.68 inches;

wherein the outer mantle layer is harder than the inner mantle layer, the inner mantle layer is harder than the outer core layer, the outer core layer is harder than the intermediate core layer, the intermediate core layer is harder than the inner sphere, and the cover layer is softer than the outer mantle layer.