D*Alex, that's what I was thinking. Yet in a half page write up in the latest Velo News on the new DA and Record triples and associated ders they specifically mention that one of the rear ders has 13T pulleys. Can't remember which one off the top of my head.

I would think that because the diameter is larger one probably cannot retro fit other ders with the larger pulleys.

On a possibly related note, I had asked in another thread about the pulley noise when in the big ring. The answer was increased chain tension. I checked this morning and, sure enough, when I shifted to smaller cogs the noise lessened. Unfortunately, I seldom get past 52-18 so I don't get to hear the silence.