We used a 3d printed cartridge to house the wheel. This is more useful, flexible, and lighter than using metal. It also allows us to have a gear ratio, which can't be found when we use metal.

We initially used 100% infill but we then learned about perimeters (walling, shells) and later used a lower infill with higher perimeter density.

CAD of a wheel pod in Fusion 360

CAD of wheel pod assembly in Fusion 360