Cycling Equipment · Public discussion

Broken stem, the sequel?

Started by Chris Zacho "Th · · Last activity · 29 posts · 1,216 views

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Cycling Equipment
Published
13 March 2004
Last activity
19 March 2004
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Chris Zacho "Th
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  1. Werehatrack <[email hidden]> wrote in message news:<[email hidden]>...

    Quoted message said:

    Perhaps the problem is that there is no two-bolt design
    that is as robust as one with four. Since three different
    manufacturers have had the same kind of problem, I'd say
    that there's enough of a pattern to say it's the design
    itself, not its execution. One would be a random error;
    two a concidence. Three is prudently regarded as a pattern
    until proven otherwise.

    No. The problem is in execution, not design. Go back to the
    CPSC page on the recall of the Trek/Icon stem; the recall
    was not all Icon stems of that genre, but those with the
    narrow faceplate. The wider faceplate model was a bit
    beefier and was never recalled. The 3T recall is of the Zepp
    XL, only, and did not include the Forgie or The Stem both of
    which are two bolt stems but are a bit more robust in the
    faceplate area. The two bolt stems work, but need to be
    beefy enough to handle the job. The recalls are on the more
    gracile designs without the 'beef'.

    - rick

  2. Chris Zacho The Wheelman said:

    BTW, I decided against the Cinelli stem. I got a Richey
    WCS instead. Mounted in an "upwards" position, it too
    places the rider's weight onto the stem body, rather
    than forcing the cap to support everything. And it has
    four bolts.


    In a TOUR magazine test, in spite of the 4 bolts, the
    Ritchey WCS was not recommended. (just like 3TTT
    Forgie btw).

    Greets, Derk

  3. Chris Zacho The Wheelman said:

    Anybody here know a good source for M5 x 0.8 S.S. or Ti
    cap head screws? :-3)

    My favorite source is McMaster-Carr
    (mcmaster.commcmaster.com). Try part number 91292A191 as
    a starting point. I always get part(s) the day after I
    order them. They must have a huge warehouse and a well-
    automated system.

    --
    Dave dvt at psu dot edu

  4. Chris Zacho 'The Wheelman said:

    BTW, I decided against the Cinelli stem. I got a Richey
    WCS instead. Mounted in an "upwards" position, it too
    places the rider's weight onto the stem body, rather than
    forcing the cap to support everything. And it has four
    bolts. That is, it's supposed to. They fell out during
    shipment so my LBS gave it to me for $35 U.S.

    Quoted message said:

    I got some cap head screws at Lowe's that fit for now.
    Anybody here know a good source for M5 x 0.8 S.S. or Ti
    cap head screws? :-3)

    If you are truly worried about your stem or bolts breaking
    and bars falling off, why in hell are you thinking about
    using titanium stem bolts?

    Argh.

    High grade steel or stainless steel sounds like a good
    choice. Maybe Ritchey will tell you what the spec of the
    original bolts was.

  5. Hi Chris,

    Chris Zacho The Wheelman said:

    any reference condemning this stem, I'd appreciate it.


    TOUR july 2003

    They say the max. torque specifications are not OK. Only 4
    stem/bar combinations got their OK: the
    Tune/Schmolke,Cinelli, Deda and Syntace.

    The Ritchey didn't survive a dynamic test, during which 2
    WCS broke after
    50.000 cycles of the 200.000 that some other brands
    survived.

    Greets, Derk

  6. Quoted post said:

    Originally posted by Derk
    Hi Chris,

    Chris Zacho The Wheelman said:

    any reference condemning this stem, I'd appreciate it.


    TOUR july 2003

    They say the max. torque specifications are not OK. Only 4
    stem/bar combinations got their OK: the
    Tune/Schmolke,Cinelli, Deda and Syntace.

    The Ritchey didn't survive a dynamic test, during which 2
    WCS broke after
    50.000 cycles of the 200.000 that some other brands
    survived.

    Greets, Derk

    Where are these tests? I tried looking back for a link. Got one?

  7. Quoted post said:

    Originally posted by BaCardi
    Where are these tests? I tried looking back for a link. Got one?

    Dear Bacardi, Derk, and Chris,

    I think that this is a different test, but that
    it covers some of the stems in question:

    http://www.biketechreview.com/stems/stems.htm

    Good luck,

    Carl Fogel

  8. Chris Zacho 'The Wheelman said:

    I was wondering if I should spell out Stainless Steel
    instead of just abbreviating it "S.S.". LOL! Now, tell me
    why Ti would break. Isn't there another thread on this
    board stating how great titanium is in regards to strength
    and fatigue resistance?

    I knew what you meant by "S.S." High grade stainless steel
    bolts are quite strong and a good choice for Jesus-nut
    bicycle applications. Andrew Muzi alredy covered much of the
    rest of the argument. There are Ti bolts which are also
    strong (I believe
    6/4 Ti is over 100 ksi tensile strength and some reasonable
    fraction of that in shear). You gotta get the right kind
    of Ti, though, as lower grades are much less strong.
    Titanium bolts also have a tendency to gall. You pay a
    lot of money for a trivial weight reduction and a bolt
    which is no more secure than good steel and may have
    additional hassles.

    In general, my point is: Why worry at length about stem
    design as you did, and then follow a decision making process
    that leads to using a quite light stem (Ritchey WCS, right?)
    with potentially lower-than-spec or weight-weenie bolts?

    In the meantime, here's a source for bolt strengths and
    graded bolts (I have no personal experience, but they have a
    nice chart):

    boltdepot.comboltdepot.com boltdepot.comG
    rade_markings_properties.htm

  9. Chris Zacho The Wheelman said:

    I was hoping for a link, but you gave the essentials.


    There is no online article: you can order most tests by
    faxing a special fee number.

    Quoted message said:

    I'll keep an eye on the stem, Was the article testing road
    or ATB stems?


    Road only.

    I wouldn't worry too much, but wouldn't tighten to the max
    specified torque.

    Greets, Derk

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