Bicycle sprocket wheel unit and mounting unit for cooperating with sprocket wheels

A mounting unit comprising:

• an integral ring-shaped plate which is made by way of pressing, the mounting unit including a hub connection hole defined in a center thereof, and comprising a first disk, a second disk and a third disk, the first, second and third disks sharing a center of the hub connection hole, an outer periphery of the second disk connected to the inner periphery of the third disk, an inner periphery of the second disk connected to the outer periphery of the first disk, the inner periphery of the second disk being shorter than the outer periphery of the second disk, the second disk being a cone-shaped face and protruding from a front face of the mounting unit, a first fixing portion formed on a front face of the third disk, a second fixing portion formed on a rear face of the third disk, the third disk having multiple fixing apertures defined therethrough which are evenly spaced apart from each other, the second disk having multiple third fixing portions formed on the outer periphery thereof, and the second disk having multiple fourth fixing portions formed on the inner periphery thereof.