Why can I not put an edge loop around this model? I am unable to add an edge loop around the outer edge of this model (around the rim), and it is driving me crazy trying to work out why.


All faces in the model are quads (verified with Select Faces By Sides);
I have removed all doubles;
The relevant faces seem to be connected (verified by dragging them about).


Despite the above, you can see that any edge loop will only go through 6 faces and stop. 

I made the object using mirror and array modifiers. I expect this is reason, but I cannot explain the persistent effect now that the modifiers have been applied.

I'm sure this is embarrassingly obvious, but I am clueless.
I don't know why it happens but I know how to resolve:
Every part of the mesh where there are 2 faces loops between two spokes, delete the 4 vertices inbetween (they also are not selectable as edge loop), then recreate them, extruding or bridging edge loops and then loop cutting and grabbing in the right position.

Edit: deleting and recreating just one vertex is enough.