In regards to SRAM changing the design of their own plastic PF30 BB, I noticed one quite significiant difference.
The original SRAM BB had these metal bearing protecting seal things on the outside of the bearings (click to embiggen):
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But the new SRAM BB now has these plastic outer bearing protectors that fit inside the bearing, where your spindle makes contact with the bearing inner, like so:
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This could be a good thing or a bad thing. The original one sucked so anything might be an improvement.
But this also has an interesting knock on effect, the inner dimension of the bearing of the SRAM BB is now 30.5mm to allow for that plastic insert. The usual BB30 (6806 2RS) bearing was 30mm.
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However I don’t think this will be much of a problem, these plastic BBs are not designed to have their bearings replaced. However I was hoping that if the plastic bearing protecting sleeve actually helped improve bearing life, I was contemplating using it on my wheels mfg BB with new bearings, but sadly the sleeve doesn’t fit in the standard BB30 bearings.
Please don’t consider this my endorsement for the new SRAM PF30, merely illustrating it has changed!