Rear hub thru-axle for human powered vehicle

A rear hub thru-axle is provided for a human powered vehicle. The rear hub thru-axle is basically provided with a first axle portion and a second axle portion. The first axle portion has a first hollow interior passage defining a first interior dimension. The second axle portion has a second hollow interior passage defining a second interior dimension. The first axle portion is connected to the second axle portion in an axial direction with respect to the rear thru-axle. The first interior dimension of the first hollow interior passage is larger than the second interior dimension of the second hollow interior passage.