Sorry to disagree with some of you here, but yes, a polarizer can have significant effect on metallic surfaces, even chrome. True, Specular highlights will see little effect from polarization on glass, chrome and other smooth reflective surfaces, but you will find that diffuse, reflected highlights can in fact be controlled (heightened, darkened, and moved) to a great degree on all of these surfaces with the use of either a linear or circular polarizer. The statement that light reflected from metal "is not polarized" is correct, however it misunderstands the issue, as light reflected from virtually any object or surface "is not polarized" (that's what the polarizing filter does, my friend). In fact the light coming off a smooth surface is probably more polarized than that coming off a diffuse surface, which is one of the reasons a polarizer has little effect on it.
In reality though....someone shooting chrome wheels in a studio needs to invest in some foamcore, white fabric, white paint, and perhaps a few grey panels long before pulling out the polarizer. Typical issues in lighting chrome are a simple exercise in controlling contrast, and understanding that when you are photographing mirror like surfaces like chrome...it's the objects (lights, surfaces, garage furniture) reflected in the chrome that you need to worry about, so surrounding the entire wheel in white is a good starting point. After that you add selective shadowing using your lights or grey cards to add definition.
Once you have it all worked out, though. It's amazing how a well-lit piece of chrome can be "reshaped" with the use of one of those magic $100 pieces of glass.
