Bicycle rear sprocket assembly

A bicycle rear sprocket assembly configured to be mounted to a sprocket support portion of a bicycle rear hub assembly, the bicycle rear sprocket assembly comprising:

• a first sprocket including:
• a first bicycle inbound facing surface;
• a first bicycle outbound facing surface opposite to the first bicycle inbound facing surface in an axial direction parallel to a rotational center axis of the bicycle rear sprocket assembly;
• a first opening having a first diameter that is smaller than a radially outer diameter of the sprocket support portion of the bicycle rear hub assembly;
• and
• a first torque-transmitting structure provided to the first bicycle inbound facing surface and configured to transmit pedaling torque to a second sprocket adjacent to the first sprocket without another sprocket between the first sprocket and the second sprocket in the axial direction;
• and
• a lock member including:
• a main body having a first axial end configured to pass through the first opening of the first sprocket and a second axial end opposite to the first axial end in the axial direction, the first axial end being positioned closer to an axial centerline of the bicycle rear hub assembly than the second axial end in a state where the bicycle rear sprocket assembly is mounted to the bicycle rear hub assembly;
• a male thread portion provided to the first axial end, the male thread portion being configured to engage with a female thread portion of the bicycle rear hub assembly in the state where the bicycle rear sprocket assembly is mounted to the bicycle rear hub assembly;
• and
• a radial projection extending radially outwardly from the second axial end with respect to the rotational center axis to restrict axial displacement of the first sprocket with respect to the sprocket support portion of the bicycle rear hub assembly in the state where the bicycle rear sprocket assembly is mounted to the bicycle rear hub assembly.