I had ceramic bearings installed in my 2.4 when I bought my wheelset from Competitive Cyclist. I'm assuming if anybody can get a bearing swap right, these guys can.
Ar around 2500 miles (last week) on the rear, I started having shifting problems on the 11T. I swapped the wheel to another bike and within 2 days had shifting problems on it with the 11T. Odd, right?
So, giving the freehub/cassette a firm yank, I noticed some deflection that seemed wrong.
Took the PT apart myself (206 mile ride the next day, didn't want to wait) and noticed something gritty inside the grease. Ceramic. Almost had the texture of sandblasting media.
One of the cages separated and let the little ceramic balls go. Nice, huh?
Fortunately, CC sent me the original bearings which were pulled out and since they felt smooth, I changed them all out.
I have to say, I'm not completely convinced about the difference in drag with ceramic bearings. I think the grease you use for the freehub and the bearings would induce more drag than the balls anyway. I think a lot of it is just the latest marketing fad. Apparently though, it works, because I have ceramics on every part of my Cervelo.
Re: PT bearings 
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