Will a 16" rim fit a 2007 X3.

Just wondering if a 16" BMW rim will fit a 07 X3?

I don't believe so; the smallest wheel/tyre size BMW makes available on a X3 is the P215/60 R17 size.

I have the base 17 inch wheels on my X3, and they only clear the brake calipers by about 1/4 inch. So I think you would get interference with a normal 16 inch wheel.

Obviously, clearance also depends on the design of the wheel. It is possible there is a 16 inch wheel designed to clear the brakes.