How to fix the center of models' rotation?

Hello everybody! I have one question, that keeps me on the alert for a long time.
Why some models on the preview don't spin around their centers?
And are there any ways to fix it?
Thanks for possible answers.

compared to a Cartesian system (x;y) the actual car is not centered (see drawing)

you can center it easly, but you must have good knowledge of modding, otherwise you could have other serious problems when the car go on track