To complete the build you will need:
 - 6 x M2 screws 10mm long
 - 1 M3 nut
 - Glue

The screws are used to keep the front and back parts together. You probably need to sand the nut to reduce its height (around 3-4 mm height) and then glue it to the cap.

The idea is tighten the M3 nut (not the one used in the cap) of the wheel with using a tool (see image above). When the wheel is in place and tighten, with your fingers tighten the cap over the other nut.

Print "Rim out" and "Cap" at 0.10. I have included the same files but in a position that improves the result but you will need to use supports.

Print "Rim in" and "Ring" at 0.15 or 0.20mm layer height.