@NickC - Great ideas! I like the background idea for sure. I think the wheel/tire thing may get lost when it gets shrunk down to size. I think it's somewhere around 16x16 or 20x20 pixels, so not a lot to work with.
Just looking at what we have right now, it looks to be around 14x14 or 17x14 or 7x7 depending on which annotation you are looking at. I don't know how it works out in the coding. I think most (if not all) of them are coded and not images. That may make it a bit harder in and of itself.
@DucatiKiller there's also the reality that these wheels are super old and no longer pretty. The idea of having pretty wheels even in the winter is appealing....