I would guess whoever did the box art graphics didn't know there were metal components in the kit The wheels containing what you refer to as a sleeve should be glued together, but the sleeve (usually referred to as a poly cap) should not be glued and free to rotate inside the wheel assembly. The poly cap is an interference fit with the axle, press it on and the wheel assembly will rotate. The inner wheels don't need to be glued, the outer wheels will prevent them from coming off the axle and the track teeth keeps them aligned. Thank you! It turned out that the first set of wheels needing the poly insert, actually required the Poly S not Poly M! And fitted better by inserting the first wheel on the axial, then fitting the Poly M, then glueing the second wheel to the first!