I like your shot - it's a good composition and good depth of field, rendering the rear wheel just a little fuzzy.
The colors are true t the weathering these wheels have seen.
"Grunging it up" could certainly render a more "dramatic" image for you, if you wanted to see what that would be like. Sepia-fying it would also complement your great coqboy and horse shot from earlier
However, I like it the way it is. There is a certain quiet "mood" to it. I wonder how it would look in more contrasty B&W? Daguerro-type or Noire type, I'm thinking.
Nice shot patti!