I'm trying to change a tire on my 2002 Subaru Forester, but the aluminum wheel will not come off. All the lug nuts are completely off, I've tried banging it with a rubber mallet, etc., but with no success. Is there anything else I have loosen before it will come off? Any advice?  Thanks!

What you've discovered is that aluminum (your wheel) and cast iron (your brakes) do not belong together.  When  you place the two together a chemical, electrical or mechanical reaction is set up that bonds the two unlike metals together (somebody help me on this please).  I do not know how to avoid this -- maybe putting a thin (45 mil) sheet of rubber between the two -- but my breakdown kit includes a solid 2" x 2" x 18" long chunk of hardwood and a large hammer (24 oz.).  After jacking up my 2005 Mazda 6 and placing an axle stand by the wheel I'm working on, I place one end of the hardwood against one of the "spokes" on the rim and smash the other end with the flat of the hammer).  Usually one or two blows per spoke will loosen the rim -- it's a real mess if you have to do this in snow or rain.

The more often you do this, the less likely it is that you'll have to do this.

Good Luck!

I am sure you have your tire changed by now, but this is a common problem when using aluminum wheels.  Once you realize you have a problem, hitting itwith a hammer should be your last resort as aluminum wheels can break.  What usually works for me is to loosen the lugs, and then tighten them almost finger tight, let the car back off the jack, then start the car and move it very slowly back and forth.  You don't want to be able to see threads on the wheel studs when you do is, the nuts should be just barely loose.  9 times out of 10 this works.  If it fails, put the car on jackstands and then put the jack under the tire and jack it up.  If the jack on the tire lifts the car off the jackstand, than this will not work either.  If you do have to resort to using a hammer, and I have, use a thick piece of wood layed flat against the tire to distribute the force of the hammer to protect the wheel.  Once you have it off, to stop it from happening again, clean the surfaces where they touch, use some sand paper or steel wool to remove any rust front the brake drum or rotor, and then paint it using a spray paint made for rusty surfaces, or apply a very thin coat of either dielectric grease or anti-seize.  This should prevent the problem from happening again.

 As a side note, aluminum wheels expand and contract at a differnt rate than steel and cast iron.  Therefore, it is important to recheck the torque of your lugnuts a couple times after reinstalling a wheel.  When I have had my wheels off, I carry a torque wrench with me and recheck them after 15 miles, and again after about 60 miles.  Using a torque wrench is very important with wheels.  Too little torque and your wheels can work themselves loose.  Too much torque can break studs, damage wheels, and warp brake parts causing a vibration while driving.