Reason:
The replaceable Dunlop rubber seal has a height of 10mm overall, but only 4mm which include 6mm out outstanding
Thread of the Dunlop-valve.
Add to that the mass of truly massive head and the associated tubing, which still by the enormous pressure of pumping expands a little and thus moves minimally be effected in a short time that the head falls off simply. (Leverage)
But his big weight and the fact that only a "ring" of 4mm 10mm Seal Dunlop rubber includes the actual Dunlop valve, makes it almost useless for this type of valve.
I'm really surprised that this nobody noticed here.
It is strange that SKS manufactures a product that is not to handle at least one of 2 types of valves.
One wonders: do not test the such a thing? -If so, how come to a positive result?
Become SKS consult it.