Saddle Rail Failures

Discussion in 'Cycling Equipment' started by Harris, Feb 13, 2003.

Thread Status:
Not open for further replies.
  1. Harris

    Harris Guest

    Two questions on saddle rails:

    1) Are tubular saddle rails more likely to fail than solid rails?

    2) Would tubular steel rails be more reliable than solid Ti?

    Thanks, Art Harris
     
    Tags:


  2. Dion Dock

    Dion Dock Guest

    1) yes
    2) It doesn't matter. Nothing is more important than saving weight.

    -Dion

    "Harris" <[email protected]> wrote in message
    news:[email protected]...
    > Two questions on saddle rails:
    >
    > 1) Are tubular saddle rails more likely to fail than solid rails?
    >
    > 2) Would tubular steel rails be more reliable than solid Ti?
    >
    > Thanks, Art Harris
     
  3. A Muzi

    A Muzi Guest

    "Harris" <[email protected]> wrote in message
    news:[email protected]...
    > Two questions on saddle rails:
    >
    > 1) Are tubular saddle rails more likely to fail than solid rails?
    >
    > 2) Would tubular steel rails be more reliable than solid Ti?

    That leaves too many variables, like what kind of steel, how thick and how well made (uniform)
    is the tube?

    Generally Ti is far inferior to steel here AEBE, but all else is seldom equal.

    Titanium rail failures are common yet steel failures, even among a vastly larger sample with vast
    quality differences, are not common.
    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  4. A Muzi wrote:
    >
    > "Harris" <[email protected]> wrote in message
    > news:[email protected]...
    > > Two questions on saddle rails:
    > >
    > > 1) Are tubular saddle rails more likely to fail than solid rails?
    > >
    > > 2) Would tubular steel rails be more reliable than solid Ti?
    >
    > That leaves too many variables, like what kind of steel, how thick and how well made (uniform) is
    > the tube?
    >
    > Generally Ti is far inferior to steel here AEBE, but all else is seldom equal.
    >
    > Titanium rail failures are common yet steel failures, even among a vastly larger sample with vast
    > quality differences, are not common.

    I second that.

    Here in my office, I've got a broken titanium saddle rail. When the time comes to explain metal
    fagigue, I pass it around. Nice classic example, with pretty "beach marks."

    --
    Frank Krygowski [email protected]
     
  5. On Thu, 13 Feb 2003 12:36:47 -0500, Dion Dock wrote:

    > 1) yes
    > 2) It doesn't matter. Nothing is more important than saving weight.
    >

    Then why, I wonder, bother with that heavy nasty old saddle at all? Just leave it off entirely, and
    think of the grams saved. ;-)
     
  6. Richard Ney

    Richard Ney Guest

    "A Muzi" <[email protected]> wrote

    > > Two questions on saddle rails:
    > >
    > > 1) Are tubular saddle rails more likely to fail than solid rails?
    > >
    > > 2) Would tubular steel rails be more reliable than solid Ti?
    >
    > That leaves too many variables, like what kind of steel, how thick and how well made (uniform) is
    > the tube?
    >
    > Generally Ti is far inferior to steel here AEBE, but all else is seldom equal.
    >
    > Titanium rail failures are common yet steel failures, even among a vastly larger sample with vast
    > quality differences, are not common.

    What's the failure mode? A bend, kink, or something catastrophic?
     
  7. Harris

    Harris Guest

    "Richard Ney" wrote:

    Art Harris wrote:
    > > > Two questions on saddle rails:
    > > >
    > > > 1) Are tubular saddle rails more likely to fail than solid rails?
    > > >
    > > > 2) Would tubular steel rails be more reliable than solid Ti?
    > >
    A. Muzi wrote:
    > > That leaves too many variables, like what kind of steel, how thick and
    how
    > > well made (uniform) is the tube?
    > >
    > > Generally Ti is far inferior to steel here AEBE, but all else is seldom equal.
    > >
    > > Titanium rail failures are common yet steel failures, even among a
    vastly
    > > larger sample with vast quality differences, are not common.
    >
    > What's the failure mode? A bend, kink, or something catastrophic?

    Shear failure. The reason for my question is that most current saddles are not available with solid
    steel rails. I'm looking for the next strongest type. It gets confusing when you start seeing terms
    like Vanadium and Manganese.

    A booklet that came with my Rolls Classic saddle shows the labeling that Selle San Marco uses. They
    use "C" for steel, "M" for Cr-Mo (not manganese), and "T" for titanium. Since Cr-Mo IS steel this is
    very confusing. I THINK they use "M" to mean tubular Cr-Mo, and "C" to mean solid steel.

    I had a hollow Manganese rail fail once, so I would definitely avoid that. I'm trying to determine
    the relative strength of hollow Cr-Mo vs. solid Ti since those seem to be the most available types.

    Art Harris
     
  8. Robin Hubert

    Robin Hubert Guest

    It seems to me that all the saddle rail failures I've seen are usually due to the saddle being too
    far back (as in, all the way) on the rails and/or abuse.

    Robin Hubert
     
  9. A Muzi

    A Muzi Guest

    > > > Two questions on saddle rails:
    > > > 1) Are tubular saddle rails more likely to fail than solid rails?
    > > > 2) Would tubular steel rails be more reliable than solid Ti?

    <[email protected]> wrote
    > > That leaves too many variables, like what kind of steel, how thick and
    how
    > > well made (uniform) is the tube? Generally Ti is far inferior to steel here AEBE, but all else
    > > is seldom equal. Titanium rail failures are common yet steel failures, even among a
    vastly
    > > larger sample with vast quality differences, are not common.

    "Richard Ney" <[email protected]> wrote in message
    news:[email protected]...
    > What's the failure mode? A bend, kink, or something catastrophic?

    A rail just snaps, directly behind the clamp..

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  10. Richard Ney wrote:
    >
    > What's the failure mode? A bend, kink, or something catastrophic?

    Again, for this one it was fatigue in bending, directly behind the clamp. That means a small crack
    formed at a high-stress area, gradually worked its way through the solid rail, and the last little
    bit hanging on snapped in two on a bump. It's catastrophic.

    The owner stopped, picked up the pieces, and rode home standing.

    --
    Frank Krygowski [email protected]
     
  11. Harris

    Harris Guest

    "Frank Krygowski" wrote:

    > Again, for this one it was fatigue in bending, directly behind the clamp. That means a small crack
    > formed at a high-stress area, gradually worked its way through the solid rail, and the last little
    > bit hanging on snapped in two on a bump. It's catastrophic.
    >
    > The owner stopped, picked up the pieces, and rode home standing.

    On a group ride I was on, one of the riders broke a rail. He was able to position the broken part
    inside the seat post clamp and finish the ride sitting.

    Art Harris
     
  12. Art Harris <[email protected]> wrote:
    > "Richard Ney" wrote:
    > A. Muzi wrote:

    > > > Titanium rail failures are common yet steel failures, even among a vastly larger sample with
    > > > vast quality differences, are not common.
    > > What's the failure mode? A bend, kink, or something catastrophic?

    > Shear failure. The reason for my question is that most current saddles are not available with
    > solid steel rails. I'm looking for the next strongest type. It gets confusing when you start
    > seeing terms like Vanadium and Manganese.

    Marketing speak. Vanadium and manganese are alloying elements in steel (ever buy a "chrome vanadium"
    screwdriver?). For example, Reynolds 531 is manganese-molybdenum steel (as opposed to Cr-Mo which is
    chromium-molybdenum). I have a Selle Italia Sphere with "FeC alloy" rails. Duh, every decent steel
    has iron and carbon in it.

    > A booklet that came with my Rolls Classic saddle shows the labeling that Selle San Marco uses.
    > They use "C" for steel, "M" for Cr-Mo (not manganese), and "T" for titanium. Since Cr-Mo IS steel
    > this is very confusing. I THINK they use "M" to mean tubular Cr-Mo, and "C" to mean solid steel.

    As with bikes, Cr-Mo probably indicates stronger than generic steel, but then they can make the
    tubing walls thinner. I don't know that the "C" ones are solid - solid steel rails would be
    rather heavy.

    > I had a hollow Manganese rail fail once, so I would definitely avoid that. I'm trying to
    > determine the relative strength of hollow Cr-Mo vs. solid Ti since those seem to be the most
    > available types.

    I think you can assume that reasonable steels will be stronger than Ti but what you don't know is
    the relative quality of design/manufacture. Anything can fail once. Did it really just shear right
    off, no bending first? Could there have been a stress riser from the seatpost clamp?

    I hear from this thread that Ti rail failures are common. That's a bit worrisome. Any common
    features among the failures (mountain bikes, large riders, poorly designed seatpost clamps, seat all
    the way back on the rails)?
     
  13. Benjamin Weiner wrote:
    >
    > Duh, every decent steel has iron and carbon in it.

    So do all the indecent steels!

    --
    Frank Krygowski [email protected]
     
  14. Phil

    Phil Guest

    > I hear from this thread that Ti rail failures are common. That's a bit worrisome. Any common
    > features among the failures (mountain bikes, large riders, poorly designed seatpost clamps, seat
    > all the way back on the rails)?

    I'm 140lbs. Bent an 8mm solid steel rail during a MTB race on a BMX saddle. Somewhat of a harsh
    crash that gave me a bruise on my bum for a couple days afterwards. It sits on a 20 or 30-degree
    slope to the side now.

    Phil, Squid-in-Training
     
  15. Harris <[email protected]> wrote:
    > "Richard Ney" wrote:
    > A. Muzi wrote:

    > > > Titanium rail failures are common yet steel failures, even among a vastly larger sample with
    > > > vast quality differences, are not common.
    > > What's the failure mode? A bend, kink, or something catastrophic?

    > Shear failure. The reason for my question is that most current saddles are not available with
    > solid steel rails. I'm looking for the next strongest type. It gets confusing when you start
    > seeing terms like Vanadium and Manganese.

    Marketing speak. Vanadium and manganese are alloying elements in steel (ever buy a "chrome vanadium"
    screwdriver?). For example, Reynolds 531 is manganese-molybdenum steel (as opposed to Cr-Mo which is
    chromium-molybedenum). I have a Selle Italia here with "FeC alloy" rails. Duh, every decent steel
    has iron and carbon in it.

    > A booklet that came with my Rolls Classic saddle shows the labeling that Selle San Marco uses.
    > They use "C" for steel, "M" for Cr-Mo (not manganese), and "T" for titanium. Since Cr-Mo IS steel
    > this is very confusing. I THINK they use "M" to mean tubular Cr-Mo, and "C" to mean solid steel.

    Cr-Mo is just one type of steel, stronger than generic. I don't know that the "C" ones are solid.

    > I had a hollow Manganese rail fail once, so I would definitely avoid that. I'm trying to
    > determine the relative strength of hollow Cr-Mo vs. solid Ti since those seem to be the most
    > available types.

    I think you can assume that reasonable steels will be stronger than Ti but what you don't know is
    the relative quality of manufacture. Anything can fail once. Did it really just shear right off, no
    bending first? Could there have been a stress riser from the seatpost clamp?

    Andrew Muzi said Ti rail failures are common. Izzat so? That's a bit worrisome. Any common features
    among the failures (mountain bikes, large riders, poorly designed seatpost clamps, seat all the way
    back on the rails)?
     
  16. Sam Yorko

    Sam Yorko Guest

    Phil wrote:
    >
    > > I hear from this thread that Ti rail failures are common. That's a bit worrisome. Any common
    > > features among the failures (mountain bikes, large riders, poorly designed seatpost clamps, seat
    > > all the way back on the rails)?
    >
    > I'm 140lbs. Bent an 8mm solid steel rail during a MTB race on a BMX saddle. Somewhat of a harsh
    > crash that gave me a bruise on my bum for a couple days afterwards. It sits on a 20 or 30-degree
    > slope to the side now.
    >
    > Phil, Squid-in-Training

    Let me get this straight: your bum now sits on a 20 or 30-degree slope to the side now? Um, wow.

    Sam
     
Loading...
Thread Status:
Not open for further replies.
Loading...