In general or specifically this car?
In general:
> determine the radius of the fender
> calculate with a factor (1.1 or something?) the radius of the wheel
> determine the width of the wheel
You know the turning point of the wheel, which is the point at which it connects to the axle. Follow standard trig functions to determine the position of the segment of wheel at a certain radius, according to the diagram in my image. The front of the rim theoretically stays an ellipse, but if you need to start fucking around with Beziér curves you might as well simulate it in blender or something. What are you trying to do?