Thias
Klein Fan
50mm chainline is OK.
Did you check the distance between the derailer and the big chain ring vertically? The smaller the distance, the better.
What kind of chain do you use?
Does the derailer match the chain ring size?
Usually the chain will only fall off the big chain, if you overshift it. That would be solved by reducing the upper limit stop.
But hey, Sheldon has it all: http://sheldonbrown.com/derailer-adjustment.html
Did you check the distance between the derailer and the big chain ring vertically? The smaller the distance, the better.
What kind of chain do you use?
Does the derailer match the chain ring size?
Usually the chain will only fall off the big chain, if you overshift it. That would be solved by reducing the upper limit stop.
But hey, Sheldon has it all: http://sheldonbrown.com/derailer-adjustment.html