The steel wheels on my winter tires have a center hub that's exposed. Supposedly Subaru does sell caps for them somewhere, but they're too expensive for what they are.
This is a perfect chance to make them! The hub outer diameter is 62mm, and there's a small ridge near the edge for some tabs to bite into. They fit on pretty snugly and I don't think they'll ever come off on their own, but they aren't impossible to remove by hand.
Printing Instructions:
Use any filament, default infill is fine. I advise a line or two of supports for the center, but in reality even if there's a bit of droop nobody will see it.
The 3MF file is for PrusaSlicer and contains all of the necessary supports and optimizes the layer heights - 0.1mm high for the curve, and 0.25mm for the rest. It also has a colour change for the logo on top. I used Polyterra Charcoal PLA and PolyLite Silk Blue PLA.
The author marked this model as their own original creation.