If you learn to use 3 levers on a tire, the toughest tires are real easy to mount and dismount. Also, steel core vs. just plastic levers made a big difference for me.
skip to 3:40 and the guy shows how to use 2 levers to take off a tire (yeah it is motorcycle, but works the same)
http://www.youtube.com/watch?v=0Pfp2...eature=related
then you can do the reverse to put a tire on, but lots of people say not to use levers to put to a tire.