Cycling Equipment · Public discussion

how is a frame's BB shell determined if in spec?

Started by jasong · · Last activity · 13 posts · 542 views

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Cycling Equipment
Published
23 March 2007
Last activity
24 March 2007
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jasong
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13
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  1. I've recently bought a new frame. I can't install 1 new bottom bracket in it, because the shell is distorted. Another one I can get in there, but needing to use more and more force as the BB's ends approach the edges of the shell. When getting that one further in, I can already feel the increase resistance on the spindle, presumable from the frame's shell causing the cartridge to distort and further bind the spingle against the ball bearings inside.

    The manufacturer is implying that this can't be a warranty item. Of course, this means the frame must be replaced, which is very bad for him.

    How is a BB objectively determined to be in spec?

    I can see the disparity as I screw in the drive side of the BB, easily being able to see the gap difference from side to side.

    (later added:

    I didn't mention another part of my test.

    I installed both BBs with no problems (hand tightened all the way) into 2 other blank, new frames. I've never had a BB install problem in 30+ times. Each side of the cartridge BBs install fine, its that there's an inherent tolerance that the shells assume as they get closer to being fully threaded in and need to start gently touching each other. If the BB shell is out, then you simply can't thread each side in, or you must thread them with a lot of force.

    I could get the BBs started by hand into the suspect frame. I really think the shell was either poorly tapped (poor alignment between the opposing sides) or that the shell was tapped and then welded, and was distored during the welding.

    Since I have an older frame by the same mfctr, I tried removing its BB soon after. That BB had even worse problems.

    I know it's a problem in their assembly or QC; but the mfctr is implying that there is no way that a shell can be out of spec. I disagree, but don't have a way others might quantify this.

    )

  2. JASONG! house the yuan? digitize the ti and let us gander.
    why not call the local LBS asking if there's a hozan around. find the
    hozan and hozan the BB. use blue eom loctite liberally when trying the
    BB's again or go for a first try with spoonful pc blaster mixed with
    several drops of valvo synth trans oil. if the BB goes back in,
    cleaner out and redo with the blue lock for permanence.
    wanna restate the chinese ti site?

  3. http://www.biketoolsetc.com/index.cgi?id=425755932324&nr=11&b=&c=&sc=&tc=&q=taps&s=

    http://www.hozan.co.jp/cycle_e/catalog/bb_pedal/

  4. say while your there pick up a

    http://www.hozan.co.jp/cycle_e/catalog/wheel_stand/C-737.htm

  5. [email hidden said:

    "]

    Datakoll, I don't think chasing the threads will work. The metals already gone that's been used to tilt it off axis. The threads will be at a slightly different pitch. This is why it seems that screwing up the BB tapping ruins the frame.

    But I'm curious for input,

  6. A Muzi said:

    jasong wrote:

    Some new frames, especially titanium, use a pre-threaded shell which
    warps during welding. In Titanium this is a real [censored] to rectify.

    Thanks for your reply-

    it's an aluminum frame.

    I think the evidence that:

    one BB won't install, and that another one won't install without warping it's own cartridge and increasing the BB spindle resistance against its ball bearings

    Would you agree? What bike mfctr wouldn't agree?

  7. jasong said:

    I've recently bought a new frame. I can't install 1 new bottom bracket
    in it, because the shell is distorted. Another one I can get in there,
    but needing to use more and more force as the BB's ends approach the
    edges of the shell. When getting that one further in, I can already
    feel the increase resistance on the spindle, presumable from the
    frame's shell causing the cartridge to distort and further bind the
    spingle against the ball bearings inside.

    The manufacturer is implying that this can't be a warranty item. Of
    course, this means the frame must be replaced, which is very bad for
    him.

    How is a BB objectively determined to be in spec?

    I can see the disparity as I screw in the drive side of the BB, easily
    being able to see the gap difference from side to side.

    (later added:

    I didn't mention another part of my test.

    I installed both BBs with no problems (hand tightened all the way) into
    2 other blank, new frames. I've never had a BB install problem in 30+
    times. Each side of the cartridge BBs install fine, its that there's an
    inherent tolerance that the shells assume as they get closer to being
    fully threaded in and need to start gently touching each other. If the
    BB shell is out, then you simply can't thread each side in, or you must
    thread them with a lot of force.

    I could get the BBs started by hand into the suspect frame. I really
    think the shell was either poorly tapped (poor alignment between the
    opposing sides) or that the shell was tapped and then welded, and was
    distored during the welding.

    Since I have an older frame by the same mfctr, I tried removing its BB
    soon after. That BB had even worse problems.

    I know it's a problem in their assembly or QC; but the mfctr is
    implying that there is no way that a shell can be out of spec. I
    disagree, but don't have a way others might quantify this.

    Some new frames, especially titanium, use a pre-threaded shell which
    warps during welding. In Titanium this is a real [censored] to rectify.

    He owes you either a repair or a replace.
    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971

  8. Quoted message said:
    Quoted message said:

    Some new frames, especially titanium, use a pre-threaded shell which
    warps during welding. In Titanium this is a real [censored] to rectify.

    Thanks for your reply-

    it's an aluminum frame.

    I think the evidence that:

    one BB won't install, and that another one won't install without
    warping it's own cartridge and increasing the BB spindle resistance
    against its ball bearings

    Would you agree? What bike mfctr wouldn't agree?

    The questions here would be answered quite readily if you simply bring the
    frame in to a decent bike shop. As yet neither we nor a manufacturer have
    enough information to determine what's going on, and without knowing for
    sure what's going on, it's unreasonable to expect a manufacturer to assume
    that it requires replacement.

    --Mike-- Chain Reaction Bicycles
    www.ChainReactionBicycles.com

  9. Mike Jacoubowsky said:
    Quoted message said:
    Quoted message said:

    Some new frames, especially titanium, use a pre-threaded shell which
    warps during welding. In Titanium this is a real [censored] to rectify.

    Quoted message said:

    Thanks for your reply-

    Quoted message said:

    it's an aluminum frame.

    Quoted message said:

    I think the evidence that:

    Quoted message said:

    one BB won't install, and that another one won't install without
    warping it's own cartridge and increasing the BB spindle resistance
    against its ball bearings

    Quoted message said:

    Would you agree? What bike mfctr wouldn't agree?

    The questions here would be answered quite readily if you simply bring the
    frame in to a decent bike shop. As yet neither we nor a manufacturer have
    enough information to determine what's going on, and without knowing for
    sure what's going on, it's unreasonable to expect a manufacturer to assume
    that it requires replacement.

    --Mike-- Chain Reaction Bicycleswww.ChainReactionBicycles.com- Hide quoted text -

    - Show quoted text -

    If it isn't lugged steel, it ain't real. Anything else is just replace
    and ride, and my LBS has a sign over the counter 'We don't warrant
    Stupidity'
    which is excessively open and subjective imo. As far as I'm concerned,
    Stupidity is not buying lugged (531) steel, but then I
    only have one bike. A friend who has over a dozen nice bikes buys fire
    sales off ebay often so it doesn't matter much
    to him since he rarely pays over a couple of hundred dollars initially
    for a priceless classic, and up to a couple of hundred dollars to
    detail them each.
    He is a perfect bicyle fit with longer legs, so almost any bike size
    fit him perfect with just Nitto bars and Tektro brake levers if not
    equipped with ergo/sti already.

    But if it isn't steel, you better have bought it new and have a good
    relationship with the dealer. A warped BB and stripped BB are the same
    effectively,
    except the dealer will say its stripped, so the customer loses. The
    dealer wins with $300 chinese AL bike 'warranty' claims.

    And people wonder where the phrase 'steel is real' comes from.

  10. ddog said:


    If it isn't lugged steel, it ain't real. Anything else is just replace
    and ride, and my LBS has a sign over the counter 'We don't warrant
    Stupidity'
    which is excessively open and subjective imo. As far as I'm concerned,
    Stupidity is not buying lugged (531) steel, but then I
    only have one bike. A friend who has over a dozen nice bikes buys fire
    sales off ebay often so it doesn't matter much
    to him since he rarely pays over a couple of hundred dollars initially
    for a priceless classic, and up to a couple of hundred dollars to
    detail them each.
    He is a perfect bicyle fit with longer legs, so almost any bike size
    fit him perfect with just Nitto bars and Tektro brake levers if not
    equipped with ergo/sti already.

    But if it isn't steel, you better have bought it new and have a good
    relationship with the dealer. A warped BB and stripped BB are the same
    effectively,
    except the dealer will say its stripped, so the customer loses. The
    dealer wins with $300 chinese AL bike 'warranty' claims.

    And people wonder where the phrase 'steel is real' comes from.

    Why is lugged steel only real in this case? What are your experiences
    with aluminum, titanium or carbon frames?

    Lou
    --
    Posted by news://news.nb.nu (http://www.nb.nu)

  11. "Lou Holtman" <[email hidden]> schreef in bericht
    news:[email hidden]...

    Quoted message said:
    ddog said:


    If it isn't lugged steel, it ain't real. Anything else is just replace
    and ride, and my LBS has a sign over the counter 'We don't warrant
    Stupidity'
    which is excessively open and subjective imo. As far as I'm concerned,
    Stupidity is not buying lugged (531) steel, but then I
    only have one bike. A friend who has over a dozen nice bikes buys fire
    sales off ebay often so it doesn't matter much
    to him since he rarely pays over a couple of hundred dollars initially
    for a priceless classic, and up to a couple of hundred dollars to
    detail them each.
    He is a perfect bicyle fit with longer legs, so almost any bike size
    fit him perfect with just Nitto bars and Tektro brake levers if not
    equipped with ergo/sti already.

    But if it isn't steel, you better have bought it new and have a good
    relationship with the dealer. A warped BB and stripped BB are the same
    effectively,
    except the dealer will say its stripped, so the customer loses. The
    dealer wins with $300 chinese AL bike 'warranty' claims.

    And people wonder where the phrase 'steel is real' comes from.

    Why is lugged steel only real in this case? What are your experiences with
    aluminum, titanium or carbon frames?

    Lou

    Or filled brazed and tig welded steel frames for that mather?
    For steel is real
    It's a religion Lou so why bother ;-)

    Taeke

    Quoted message said:

    --
    Posted by news://news.nb.nu (http://www.nb.nu)

  12. right but how can the manufacturer object? the 2 LBS did my frame's BB
    without great cost. if the BB giving problems has an inch plus female
    threads then a fairly low thread percentage plus lock holds the
    cartridge-if the manufacturer won't take it back.

  13. is the frame from:

    www.xacd.com.cn/about.htm

    www.xacd.com.cn

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