Really cool project Russell!
I can see the model is a ('scuse the pun) 'vehicle' for you for getting to grips with 3D printing, but the Luddite in me says the money could be invested in a good lathe?!
You certainly have the skills to machine that wheel and I would bet it would be more satisfying than having a part land on your doormat (and be better finished to boot!).
Interesting build though!
