After trying a block spacer in my dynafit crampons, and then trying the blue foam method, I'd like to put my enthusiastic support behind Amar's setup. The block spacers were fine when I was climbing, but then became unusable if I needed to cruise on the flats. The foam gives the support for positive purchase when climbing, and also works OK for the flats.
I thought B&D spacers were meant to address the gap that could exist if you used their mounting plate with a binding lifted plate (like a telemark binding), or for the gap that would sometimes exist with vibram-soled boots, not for heal lifter spacing.
This spacer is meant to address the problem of ski crampons not digging in when using the heel lift- on a Fritschi or other binding, the crampon penetration is less affected by using heel lifters, but with the dynafit, even going to the first riser level significantly decreased penetration depth- the spacer pushes the crampon deeper into the snow under foot. A few days of negotiating the refrozen crust in the Central Cascades in the last week has convinced me of the utility of the spacer, and if you got to a point where they were causing a problem of some kind, 10 seconds with a sharp tool would return the crampons to their former nudity.
