Ironically enough, the vanagon jack is perfect for separating tire beads.
Put the jack in the regular jack point, lay the wheel on the ground, and
crank away.
Position the jack's base to press against the sidewall near the rim.
I have dismounted many tires this way.  It's much faster than driving to a
tire shop and waiting for someone to screw your wheels up.
The last time I went to Don Olson  to have tires mounted and balanced they
put one tire on backwards.
This was after I made great pains to explain to the service manager which
side went out, which side went in.
I got one of each.
I complained, the tire jock changed the tire he did wrong, this time ripping
a large chunk of rubber off the tire bead as he hastily mounted it.
I complained about this, they told me it was still holding air, everything
was fine.
So, screw Olson.  Back to dis/mounting tires the old-fashion way for me.
-I even take the wheels off my cars and haul them in to have balanced.
Don't want to chance somebody jacking my vehicles up.