by thisisatest on Tue Nov 13, 2012 8:54 am
To clarify:
Specialized adapters may work with pf30 if their outer diameter (the part that sits OUTBOARD of the bearings is not greater than 42mm. For BOTH pf30 and bb30, the bearings are the same, 42*30mm, pf30 adds a plastic sleeve over their bearings to bring the overall OD to 46mm. If the specialized adapter is larger than 42mm, it may possibly rub the pf30 plastic cup.
Carbon osbb fits into specialized frames, they are 61mm wide and have a hole 46mm in diameter. Here's the important part: when you add their osbb cups to their frame (unlike the similar, but not the same pf30), the TOTAL width is 68mm and the osbb cup ID is 42mm.
Therefore,
Carbon osbb frame + carbon osbb cups = bb30 dimensions.
The specialized adapters for campy are intended to work with bb30 dimensions. Pf30 is largely the same except for a small plastic lip protruding past the frame.
If now you're thinking, "Well, then why don't I just use campy's 68*42 OS-fit cups in the carbon osbb cups?" The reason you don't want to do that is because the potential for prying out is high when installing those outboard campy cups into the specialized plastic ones. That's the whole reason specialized came up with another solution.