Bronze bushes work for bearings (still needs a lathe/ but not ball bearings). Chains can be belts of horsehair (or any civilisation with wire, tube and sheet me

Bronze bushes work for bearings (still needs a lathe/ but not ball bearings). Chains can be belts of horsehair (or any civilisation with wire, tube and sheet metal can make a modern chain) or a treadle works okay. Spokes can be wooden. The main limiting factor is probably the pnuematic tyre and smooth roads.