Sprocket support body and bicycle rear hub assembly

A sprocket support body rotatably mounted on a hub axle of a bicycle rear hub assembly, the sprocket support body comprising:

• a base support having a first axial end portion and a second axial end portion;
• at least ten external spline teeth provided on the first axial end portion of the base support and configured to engage with a bicycle rear sprocket assembly, each of the at least ten external spline teeth having an external-spline driving surface and an external-spline non-driving surface, the at least ten external spline teeth having an external-spline major diameter equal to or smaller than 34 mm;
• and
• a plurality of helical external spline teeth provided on the second axial end portion of the base support,
• a total number of the at least ten external spline teeth being equal to or larger than 20,
• one tooth of the at least ten external spline teeth having a first circumferential maximum width;
• all of the other teeth of the at least ten external spline teeth each having a second circumferential maximum width,
• the second circumferential maximum width being smaller than the first circumferential maximum width,
• the sprocket support body being free of external spline teeth of the at least ten external spline teeth having another external-spline major diameter that is different from the external-spline major diameter,
• the base support being formed of a same material as the at least ten external spline teeth,
• the sprocket support body including a larger-diameter part and an axially sprocket abutment surface provided on the larger-diameter part,
• a groove being provided between the larger-diameter part and the at least ten external spline teeth in the axial direction,
• the groove extends continuously about an entire circumference of the sprocket support body,
• the sprocket support body including a flange extending radially outwardly from the base support,
• the flange being provided between the larger-diameter part and the plurality of helical external spline teeth in the axial direction,
• the flange extending radially outward beyond a radially outermost surface of the larger-diameter part, and
• the flange having an outer portion that extends in the axial direction away from the larger-diameter part and toward the plurality of helical external spline teeth.