Abstract: An assembly for supporting axles of different diameters in a wheel, in which the wheel has a hub with a bushing receiving portion having an interior surface of a first diameter. The bushing has a portion with an outer surface of a second diameter, somewhat smaller than the hub first diameter, to fit axially into the hub receiving portion and an axle receiving portion having an inner surface of a third diameter that accepts an axle of a corresponding diameter. The hub bushing receiving portion has a first seating on its interior surface and the bushing outer surface has a second seating. A fixing element in the bushing second seating expands radially of the bushing into the hub first seating when the bushing is inserted axially into the hub bushing receiving portion and locks the bushing to the hub.