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  1. #26
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    Quote Originally Posted by OldChipper View Post
    Hmmm... maybe they tried a tiny bit TOO hard to prove they could make a disc brake bike come in below the UCI weight limit?
    Trek-Segafredo rider's bike snapped clean in half in Herald Sun Tour crash - Cycling Weekly
    I'm just glad the rotors didn't detach and start a sequel to the Texas Chainsaw Massacre

  2. #27
    tlg
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    Because clearly non-disc frames never break? There's 1000's more just like it on the Google.




    lying on the road in two pieces held together with nothing but a hydraulic disc brake hose
    Sounds to me like the hydraulic hose saved it!
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  3. #28
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    Quote Originally Posted by izza View Post
    Richie Porte hit a moped last year in the TdF. Froome hit Porte who is softer than a moped. The Pinarello breaks.

    This was the second time Froome broke a Pinarello in that race.

    Why no thread then as to why Pinarello not making a strong enough bike?


    Sent from my iPhone using Tapatalk
    Love the "softer than a moped" quote. And my yellow Mt Ventoux Running Club t-shirt is still one of my all-time favs.

    https://threadandspoke.com/products/mont-ventoux-running-club

    All the recent broken carbon discussion does worry me a tiny bit since I'm riding a repaired frame. But it has been inspected by shop and carbon repair guy and ridden a couple thousand miles since...

  4. #29
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    Quote Originally Posted by Peter P. View Post
    With a steel frame, even if it was bent would most likely remain in one piece. That means more potential for the rider to retain some semblance of control, and safety, despite the unpredictability of a crash.

    They're building carbon frames so light that they're designed to withstand "riding forces" only. That's because the fibers are oriented to the stresses at the particular locations in the frame.

    Steel is anisotropic; it has the same strength in all directions, which makes it stronger in withstanding certain forces that carbon frames ignore.

    I didn't see the crash that caused the frame in the OP to fail, but it's entirely possible applying the front brake hard or long term repeated brake application, combined with hidden fiber breakage in the underlying layers of carbon, caused the crash. The front of the frame could have been too strong for the rear half. Just speculation, of course.
    I agree except one minor addendum. In many or most applications, steel is anisotropic. In forgings, however, a grain flow Direction is often a requirement for the specific purpose of additional strength in a specific direction....especially in the aerospace industry.
    To those in uniform, both present and past, who have protected my freedoms, I thank you. I've had a good life so far.

  5. #30
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    I was broadsided by a Ram 2500 on my Emonda SLR Disc on December 26. The impact sent me from the bike lane on one side of a two lane highway to the bike lane on the other side. The only part of the frame that broke was the seatstay.

    https://imgur.com/a/i6HMw

    My frame weighed 760g...of course the less carbon you use the more likely your bike will suffer a catastrophic failure. Just keep in mind the rim brake version weighs even less because it needs less reinforcement. In all likelihood portions of the disc-brake Emonda SLR have a better chance of surviving a big crash than the same parts of the rim-brake version.

    I am a weekday/weekend 4.5w/kg warrior and the photos of the snapped Emonda donít faze me at all. Why would they unless I were an average overweight adult human male?

  6. #31
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    Quote Originally Posted by Doug B View Post
    I agree except one minor addendum. In many or most applications, steel is anisotropic. In forgings, however, a grain flow Direction is often a requirement for the specific purpose of additional strength in a specific direction....especially in the aerospace industry.
    The only steel "forged" on a high end steel bike are the "investment cast" lugs, particularly the BB shell. The seamless tubes are drawn out. Don't know how that effects grain orientation, but seems to me the grain would elongate in the direction of stretch, which would give the bike lateral stiffness and vertical compliance, the desired characteristic carbon weaves are trying to achieve.

  7. #32
    tlg
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    Quote Originally Posted by Fredrico View Post
    The only steel "forged" on a high end steel bike are the "investment cast" lugs
    Investment casting is in no way related to forging.

    The seamless tubes are drawn out. Don't know how that effects grain orientation, but seems to me the grain would elongate in the direction of stretch, which would give the bike lateral stiffness and vertical compliance, the desired characteristic carbon weaves are trying to achieve.
    Cold Drawn Seamless Tubing has grain direction parallel to the elongated direction.
    Welded Tubing can have grain direction in either direction.
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  8. #33
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    Quote Originally Posted by tlg View Post
    Investment casting is in no way related to forging.

    Cold Drawn Seamless Tubing has grain direction parallel to the elongated direction.
    Welded Tubing can have grain direction in either direction.
    Thanks for the correction. I've read that investment casting uses cold pressure in castings and forging involves heat, with the same intent: increasing granular density and therefore strength and resistance to flex.

    Yes, that's why seamless tubing is way stronger than welded tubing, that is, a sheet rolled into a tube and welded along its length, right? The stricter "grain direction parallel to elongated direction" is strong in the directions necessary to avoid folding, crumpling or breaking in a crash. Anyone tried to bend a one inch CRMO bike tube? The welded tubes are twice as thick to make up for their weakness.

  9. #34
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    " The stricter "grain direction parallel to elongated direction" is strong in the directions necessary to avoid folding, crumpling or breaking in a crash."

    And yet so many crashed steel bikes have been crumpled, right behind the head tube. It's the first place you look when considering a used steel frame - and so many unscrupulous sellers try to pass off a bent frame as a valuable bike.
    Life is short... enjoy the ride.

  10. #35
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    Quote Originally Posted by Fredrico View Post
    Thanks for the correction. I've read that investment casting uses cold pressure in castings and forging involves heat, with the same intent: increasing granular density and therefore strength and resistance to flex.

    Yes, that's why seamless tubing is way stronger than welded tubing, that is, a sheet rolled into a tube and welded along its length, right? The stricter "grain direction parallel to elongated direction" is strong in the directions necessary to avoid folding, crumpling or breaking in a crash. Anyone tried to bend a one inch CRMO bike tube? The welded tubes are twice as thick to make up for their weakness.
    Plenty of heat used for investment casting (lost wax)

    Too old to ride plastic

  11. #36
    tlg
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    Quote Originally Posted by Fredrico View Post
    Thanks for the correction. I've read that investment casting uses cold pressure in castings and forging involves heat, with the same intent: increasing granular density and therefore strength and resistance to flex.
    I don't know where you would have read that but it's in no way correct. Structurally there's no difference between regular casting and investment casting. They both use molten metal.

    Investment casting starts with a wax mold that is a duplicate of the part you want. The wax is dipped into a liquid ceramic slurry (the investment). When the ceramic hardens, liquid metal is poured in, replacing the wax. When cooled, the ceramic is broken off leaving you with your part.

    Investment castings can create very intricate and thin sections that aren't possible with traditional sand casting. In short production it's a considerably more expensive of process because you're still making a mold to make your wax part and there's more steps. But in large production it's considerably cheaper. You can mold dozens of wax parts, attach them to a stringer, coat it all in ceramic and pour once.

    Yes, that's why seamless tubing is way stronger than welded tubing, that is, a sheet rolled into a tube and welded along its length, right?
    Yes welded tubing is a sheet rolled and welded. Seamless tubing is also stronger because it's cold drawn, which hardens and strengthens it.
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  12. #37
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    Quote Originally Posted by Fredrico View Post
    Thanks for the correction. I've read that investment casting uses cold pressure in castings and forging involves heat, with the same intent: increasing granular density and therefore strength and resistance to flex.

    Yes, that's why seamless tubing is way stronger than welded tubing, that is, a sheet rolled into a tube and welded along its length, right? The stricter "grain direction parallel to elongated direction" is strong in the directions necessary to avoid folding, crumpling or breaking in a crash. Anyone tried to bend a one inch CRMO bike tube? The welded tubes are twice as thick to make up for their weakness.
    Industrial forging

    Too old to ride plastic

  13. #38
    tlg
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    Quote Originally Posted by velodog View Post
    Industrial forging
    This is a good one of multi step forging.

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