I haven't personally baked my tires, but I understand that they can be removed with the method listed at the end of the attached link, 10-15 minutes at 350 deg. As you might also read in this link, don't leave them unattended unless you want to seriously cook them.

[link]http://forums.radiocontrolzone.com/archive/index.php/t-163164.html[/link]

Let us know how you choose to get the tires off the rims, and how it works.