A turbine wheel (200, 300) for a turbocharger, comprising: a plurality of blades (202, 202') having a pressure side and a suction side, each of the plurality of blades coupled to a wheel hub (204, 304) along a root of the blade such that the pressure side of each one of the plurality of blades faces the suction side of another one of the plurality of blades about the wheel hub, with a mid-plane defined between the pressure side and the suction side of adjacent ones of the plurality of blades, each of the plurality of blades has a leading edge that terminates at a wall (220, 320) of the wheel hub, each of the plurality of blades coupled to the wheel hub along a respective blade hub camber line, the wall of the wheel hub includes a plurality of scallops (240, 240a, 240b, 240c, 340, 540, 640, 740) defined through the wall of the wheel hub at the outer circumference of the wall of the wheel hub between the adjacent ones of the plurality of blades, with each of the plurality of scallops asymmetrical about the mid-plane, characterised in that, the wall having a first radius at the leading edge of each of the plurality of blades that extends for a first circumferential distance adjacent to the suction side of each of the plurality of blades, wherein the first circumferential distance is at least 12% of a circumferential distance that extends between the adjacent ones of the plurality of blades; and for each of the plurality of scallops, the wall of the wheel hub has a second minimum radius (246, 402, 452, 502, 546, 646, 746) defined offset from the mid-plane toward the suction side of a respective one of the plurality of blades, a third minimum radius (248, 404, 454, 504, 548, 648, 748) defined offset from the mid-plane toward the pressure side of another one of the plurality of blades, with the second minimum radius less than the third minimum radius and the first radius, with each of the first radius, the second minimum radius and the third minimum radius defined between the outer circumference of the wall of the wheel hub and a center of the wheel hub. a plurality of blades (202, 202') having a pressure side and a suction side, each of the plurality of blades coupled to a wheel hub (204, 304) along a root of the blade such that the pressure side of each one of the plurality of blades faces the suction side of another one of the plurality of blades about the wheel hub, with a mid-plane defined between the pressure side and the suction side of adjacent ones of the plurality of blades, each of the plurality of blades has a leading edge that terminates at a wall (220, 320) of the wheel hub, each of the plurality of blades coupled to the wheel hub along a respective blade hub camber line, the wall of the wheel hub includes a plurality of scallops (240, 240a, 240b, 240c, 340, 540, 640, 740) defined through the wall of the wheel hub at the outer circumference of the wall of the wheel hub between the adjacent ones of the plurality of blades, with each of the plurality of scallops asymmetrical about the mid-plane, characterised in that, the wall having a first radius at the leading edge of each of the plurality of blades that extends for a first circumferential distance adjacent to the suction side of each of the plurality of blades, wherein the first circumferential distance is at least 12% of a circumferential distance that extends between the adjacent ones of the plurality of blades; and for each of the plurality of scallops, the wall of the wheel hub has a second minimum radius (246, 402, 452, 502, 546, 646, 746) defined offset from the mid-plane toward the suction side of a respective one of the plurality of blades, a third minimum radius (248, 404, 454, 504, 548, 648, 748) defined offset from the mid-plane toward the pressure side of another one of the plurality of blades, with the second minimum radius less than the third minimum radius and the first radius, with each of the first radius, the second minimum radius and the third minimum radius defined between the outer circumference of the wall of the wheel hub and a center of the wheel hub.