I cannot find the actual definition of Retail axles and wheels only.
I think I know what it means... but... Can someone point me in the right direction? The glossary did not list it that I could find. I did find this snippet: "The "retail wheels and axles" guideline means you need to use axles and wheels that come from toy cars. You can use wheels from another casting, and even axles from another casting, but you can't use some other object to make your axle - like a hat pin, or paperclip, or whatever. What you use has to come from a toy car. (You can still use axle tubes if you need, however, the axle you're shoving into the tube needs to be from a toy car)."
But really, is there a rules document that explains these requirements?