Here's a SubD version of that piece, as you can see to maintain fidelity of the shape is necessary to add a lot of geometry, I'm sure I could simplify a bit more but the point here is why would you spend so much time in such a small piece of the car, unless you are doing high end Automobile commercials where the camera is passing by some close up shots of the wheel. In the end you should put just enough detail for the kind of output you need.
For production everything must be SubD , quads only, water tight and to scale.
For video games it should be a much simpler polygon model.
Also this piece is a little harder to do because it has an odd number 15 instead of 16 cogs.