Bottom Bracket External Bearings, Ceramic Bearings, Lightness and Efficiency
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  1. #1
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    Bottom Bracket External Bearings, Ceramic Bearings, Lightness and Efficiency

    A subtitle for this may be "The Unbearable Lightness of Being (an External BB)". Would anyone care to comment on the recent article in velonews regarding friction (spin rate) of the newly available ceramic bearings for bottom brackets compared to the older models. I was intially concerned when I installed a Chorus cartridge BB from Campy for a newer Chorus 10 speed crank when it didn't spin as effortlessly as my old Campy "square taper" Record BB (circa 1987). See Velonews issue #21.

  2. #2
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    Search

    Quote Originally Posted by RickyRitalin
    Would anyone care to comment on the recent article in velonews regarding friction (spin rate) of the newly available ceramic bearings for bottom brackets compared to the older models.
    This was discussed extensively last week - do a search. The short answer is that the amount of friction is insignificant, tends to decline with time, and is mostly associated with the seals and not the bearings.

  3. #3
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    Thanks. Didn't see the thread. My apologies.

  4. #4
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    I searched for a while but can't find the post, can you give me a link please?

  5. #5
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    Try this

    Quote Originally Posted by buddhistwithafancybicycle
    I searched for a while but can't find the post, can you give me a link please?
    Just typed in "external" for the search word, and went to the 2nd page.

    forums.roadbikereview.com/showthread.php?t=80644&highlight=external

  6. #6
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    Quote Originally Posted by Kerry Irons
    Just typed in "external" for the search word, and went to the 2nd page.

    forums.roadbikereview.com/showthread.php?t=80644&highlight=external

    I can't seem to find it either and the thread you linked goes into Q factors but not the friction issue.
    Joined the other team in the name of the economy

  7. #7
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    Not to flog a dead horse, but both my external bearing cranks (a Bontrager/Truvative and an FSA) exhibited more "drag" than a quality square taper or splined spindle BB when new. But a few miles on both and they spin very nicely. It's the result of the larger contact area of the bigger bearing seals.

  8. #8
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    I typed in ceramic but did not find the thread after searching through a few pages.

    Quote Originally Posted by Kerry Irons
    Just typed in "external" for the search word, and went to the 2nd page.

    forums.roadbikereview.com/showthread.php?t=80644&highlight=external
    I find the issue curious and would like to read more about it. I have my da bb / crank sittin' on my desk, it's had a season to wear in, and it just don't spin that well. I'm not saying it's the balls, like some of ya'll are sayin it's the seals, at least as far as spinning it with my hand goes. Maybe Phil Wood bearings are the way to go.

    Anyway if that thread exists link me to it or if you guys want to hash it out again here for me instead.

  9. #9
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    Trying again

    Quote Originally Posted by Lifelover
    I can't seem to find it either and the thread you linked goes into Q factors but not the friction issue.
    This should do it: forums.roadbikereview.com/showthread.php?t=79172&highlight=external

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