Advertise on Bikeforums.net



User Tag List

Results 1 to 12 of 12
  1. #1
    Senior Member auchencrow's Avatar
    Join Date
    Apr 2009
    Location
    Detroit
    Posts
    10,013
    Mentioned
    21 Post(s)
    Tagged
    3 Thread(s)

    Pressed in bottom bracket bearings

    I just thought I'd check before prying these pressed in bearings out of an old Cannondale bottom bracket cup.

    (I can't imagine why they did this - I've replaced tons of separate bearing retainers, but never one pressed-in.)

    So - Any problem with just prying these out and replacing with loose 1/4" balls?

    - Auchen

  2. #2
    Senior Member southpawboston's Avatar
    Join Date
    Aug 2008
    Location
    Somerville, MA and Catskill Mtns
    My Bikes
    '71 Mercian, '72 Jeunet, '82 Jack Taylor, '13 Rawland
    Posts
    3,523
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    nope, no problem with just prying out that retainer ring. i had the same bottom bracket (on a cannondale!) and i just tossed the pressed-in retainers after servicing the BB.

  3. #3
    Senior Member auchencrow's Avatar
    Join Date
    Apr 2009
    Location
    Detroit
    Posts
    10,013
    Mentioned
    21 Post(s)
    Tagged
    3 Thread(s)
    Quote Originally Posted by southpawboston View Post
    nope, no problem with just prying out that retainer ring. i had the same bottom bracket (on a cannondale!) and i just tossed the pressed-in retainers after servicing the BB.
    Thank you Southpaw!
    - Auchen

  4. #4
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    take a picture of the other side of that retainer will you? It'd be interesting how they made a retainer to hold 11 balls. The fingers must really be narrow.

  5. #5
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    38,912
    Mentioned
    20 Post(s)
    Tagged
    0 Thread(s)
    Can't you just pluck out the old balls and put in new ones?

  6. #6
    Senior Member BCRider's Avatar
    Join Date
    Mar 2008
    Location
    The 'Wack, BC, Canada
    My Bikes
    Norco (2), Miyata, Canondale, Soma, Redline
    Posts
    5,409
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I suspect that the "retainer" is also part of a dust and moisture shielding system. We're used to the usual plastic or rubber seals but there was a method called "labyrinth sealing" in the old days where they used back and forth direction changes in the path for any dust or moisture to enter the bearing. The advantage to this style being that since there was no actual contact within the seal area there is no drag at all. This may be part of a similar idea depending on what the rest of the parts look like.
    Model airplanes are cool too!.....

  7. #7
    Senior Member southpawboston's Avatar
    Join Date
    Aug 2008
    Location
    Somerville, MA and Catskill Mtns
    My Bikes
    '71 Mercian, '72 Jeunet, '82 Jack Taylor, '13 Rawland
    Posts
    3,523
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DannoXYZ View Post
    take a picture of the other side of that retainer will you? It'd be interesting how they made a retainer to hold 11 balls. The fingers must really be narrow.
    no fingers on this retainer ring. the balls are loose. the ring is pressed into the cup and simply prevents the balls from falling out. the balls aren't held in place on the ring itself.

    Quote Originally Posted by fietsbob View Post
    Can't you just pluck out the old balls and put in new ones?
    not without first prying out that ring.

    Quote Originally Posted by BCRider View Post
    I suspect that the "retainer" is also part of a dust and moisture shielding system. We're used to the usual plastic or rubber seals but there was a method called "labyrinth sealing" in the old days where they used back and forth direction changes in the path for any dust or moisture to enter the bearing. The advantage to this style being that since there was no actual contact within the seal area there is no drag at all. This may be part of a similar idea depending on what the rest of the parts look like.
    that's possible, altough if that's the function of that ring, it didn't do its job very well on the bottom bracket i took apart. i can see how the ring may prevent water from the seat tube or downtube from splashing onto the bearings from inside the bike frame, but the ring does nothing to prevent dirt or water from getting to the balls from the outside, and in fact i can see how it would trap water between itself and the outer cup wall. IIRC, the BB i rebuilt like this one had no external rubber seal around the spindle.

  8. #8
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think the ring may be a seating-surface for the plastic accordion-type shield that prevents dirt & water from entering from the seat and downtubes. It can also serve as a production-aid in that it allows people to assemble the bike faster without worrying about 11 loose-bearings falling out and running all across the floor.

  9. #9
    Senior Member
    Join Date
    Mar 2009
    Location
    Boise, ID.
    Posts
    1,253
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I ran into this pulling a BB from a Specialized Hard Rock the other day. I just levered the pressed in side out and popped it back in during re-assembly.
    1993 Cannondale T700 - 1994 Specialized Rockhopper - Actionbent T1 (Electrification in progress!)

  10. #10
    Senior Member
    Join Date
    Jul 2008
    Posts
    1,253
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by BCRider View Post
    I suspect that the "retainer" is also part of a dust and moisture shielding system. We're used to the usual plastic or rubber seals but there was a method called "labyrinth sealing" in the old days where they used back and forth direction changes in the path for any dust or moisture to enter the bearing. The advantage to this style being that since there was no actual contact within the seal area there is no drag at all. This may be part of a similar idea depending on what the rest of the parts look like.
    Old days? Labyrinth seals are still around, for the same reasons they always have been. Work great, last a long time, work at high speed.

  11. #11
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm still riding my 1980's C-record BB with the spirals in the cups. Got over 50k-miles on it. Just overall it once a year and that's about it.

  12. #12
    Senior Member auchencrow's Avatar
    Join Date
    Apr 2009
    Location
    Detroit
    Posts
    10,013
    Mentioned
    21 Post(s)
    Tagged
    3 Thread(s)
    Southpaw and Danno pretty much had it right - except there was no accordion seal on this particular bike, and there was a little hard black plastic ring, but since this ring shares the same inner diameter as the cup, it was obviously intended to keep the grease inside inside, rather than contaminants outside out.
    This would make a lot of sense if you has a bin full of pregreased cups ready to pop into frames on an assembly line.

    - I'll just put new balls into it and I'll be all set!
    Thanks all.

    - Auchen

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •