Bike handling

Discussion in 'Road Cycling' started by cyclintom, Oct 24, 2018.

  1. cyclintom

    cyclintom Well-Known Member

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    Because in order to have a "light" steel bike you have to make the steel tubing lighter than the end of that endurance limit. Likewise the aluminum frames are constructed with material heavy enough that they never reach their stress limits. Early titanium bike were also built too lightly and would fail. It was common for the Colnago Bititan with dual downtubes to break the welds of the downtubes or break the tubes year the welds because of stress multiplied by leverage.

    This is all engineering 101 so why are you questioning it? I used to see Reynolds 531 frames come in relatively often with tubes with crystalline fractures around the lugs. I didn't see one case of Columbus SLX frames breaking because they were heavier gauge tubing. Likewise you can find really high stress levels breaking anything


    In this you can see every material break. Does that mean that all materials are inappropriate for bicycle design or that the material has to have the proper design for the expected stress and material properties?
    View: https://www.youtube.com/watch?v=QoV2yliPmK4
     
    #81 cyclintom, Nov 26, 2018
    Last edited: Nov 26, 2018


  2. Froze

    Froze Well-Known Member

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    TOM, WAKE UP and COMPREHEND, you DON'T have a CLUE about engineering which several of us forum members have proven time and time again because of your complete lack of knowledge and understanding of simple stuff, so I wouldn't be so snarky if I were you towards others here.

    And Reynolds never had the issues you speak up except on rare occasions just as did ALL other steel tube manufacturers including Columbus because I saw those break...BUT I never saw a Reynolds break either, so what does that prove? It proves that you and I never saw thousands of frames from all the tubing manufacturers that ever existed; and this had nothing to do with Reynolds but had everything to do with the builder applying to much heat in the brazing process. I've gone over that before with you.

    Brazing is like glue, it holds the pieces together, silver brazing has a lower brazing temperature than brass has, and when builders first started to work with brass instead of silver because it was cheaper they overheated the tubing at the lugs to high of a temperature which would lead to fracturing; and I explained that to you before, but due to your lack of engineering knowledge you obviously didn't understand that or otherwise we wouldn't be having this discussion again.

    I have a Trek 660 with 531cs tubing that was brazed with brass and done so by robots, and after over 160,000 miles later there are no issues with frame weakness...but then again no bike I have ever owned ever suffered from that EXCEPT for a Ridley Scandium bike I had where the headtube cracked at the top which Ridley denied the warranty due to fatigue after just 8,000 miles!

    And again you are wrong about Reynolds being lighter than Columbus and that's why it failed, because Columbus actually had LIGHTER tubing then Reynolds had their 531 tubing thicknesses between 0.5 to 0.8mm Columbus with the Spirit tubing got it down to .38...yet Ishiwata had it down to .22! Neither of those steels if built correctly by the builder ever had issues with fracturing.

    And since you have a huge engineer brain read this: http://www.thetallcyclist.com/2016/09/theoretical-framebuilding-part-3-metals-heat/ If you can't understand what your reading, which about 99% of the time you can't even understand what others are saying on this forum not alone more complicated stuff like the above site, then I suggest you find someone who can read it to you in simple terms.
     
  3. dabac

    dabac Well-Known Member

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    I'm questioning how you can say that steel has the worst fatigue properties.

    Seems like you're intent on mixing materials properties with design properties, using characteristics of a marginal design as "proof" of your opinion about a material property.

    I'm done with this thread. I'm not going to become the cartoon guy.
     
  4. Froze

    Froze Well-Known Member

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    Wait don't go, you're discussing engineering principles with one of the foremost engineers of our time.
     
  5. cyclintom

    cyclintom Well-Known Member

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    Oh wait, froze wants to tell us that bikes are all correctly designed and take engineering into account for endurance limits regardless of the materials because his Trek was designed by the space shuttle design crew.
     
  6. Froze

    Froze Well-Known Member

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    Oh please tommy boy PLEEEEEESEEEEE show me where I said my bike was designed by the space shuttle design crew, I'm dying to see where I posted that. I know one thing for sure, I am extremely grateful my bikes weren't designed by Tommy boy! I would have been killed by a tragic frame failure if Tommy boy had done the design work.
     
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