Jur, I have Marathon tires and this wheel (20" version):

http://www.alexrims.com/product_deta...=2&cat=2&id=71

How does the depth of the center of the rim's well compares to yours?

It is pretty flat so moving the tire to the middle does not create much clearance in the other side. Or, my technique may need improvement.

Edit: here is another 20" wheel http://www.alexrims.com/product_deta...7&cat=6&id=117 and it has a significantly deeper well. This made me to think that some rim/tire combination are easier to remove than others.

Kam