Re: Frame cracked - differences in tubing brands

Johnny Sunset aka Tom Sherman wrote:
"jim beam" (who?) anonymously wrote:
Johnny Sunset aka Tom Sherman wrote:
"jim beam" (who?) anonymously wrote:
...
indeed, but it's still not as good as seamless tube. like sora is not as good as dura-ace. arguably, they both work the same, but one has higher ultimate limits in terms of strength, lightness and fatigue....

Does Dura-Ace really provide greater strength and fatigue resistance (a citation of test results would be useful here), or merely lighter weight and better finish (particularly when compared to Ultegra and 105)?

i've not seen formal comparisons published, but let's examine what we know about dura-ace from public data:

1. dura-ace failures reported on r.b.t - i'm still on the fingers of one hand. given the sheer volume of product and time in service, that's a very important qualitative indicator.

How many failures of Ultegra and 105 have been reported? Surely, these have sold in greater quantities than Dura-Ace?

in the u.s., that's debatable! and are they used for the same mileage? serious cyclists that put in the big miles generally don't use low end groupos.


2. it's cold forged - the ultimate for strength and fatigue resistance.
3. surface finish is superb - again, best fatigue performance.

every single design element of dura-ace is the best that it can be. given that the other groupos are not cold forged and are clearly distinguishable in terms of finish or deliberately reserve scope for improvement, i'm very confident of that ranking.

However, Dura-Ace parts are lighter than Ultegra and 105, which will compromise fatigue life.

So, is there any data beyond speculation?


fatigue is a matter of design, execution and materials. on all three counts, the "speculation" accords with known factors that are /proven/ to mitigate fatigue. what's next - trying to prove that ignoring design execution and materials /doesn't/ affect fatigue?
.

Relevant Pages

  • Ebooks - Database
    ... 775 Damage in Composite Materials* ... 787 Composite Materials: Testing and Design (6th ... 798 Probabilistic Fracture Mechanics and Fatigue ... 813 Long–Term Behavior of Composites* ...
    (sci.med.nutrition)
  • Ebooks - Database
    ... 775 Damage in Composite Materials* ... 787 Composite Materials: Testing and Design (6th ... 798 Probabilistic Fracture Mechanics and Fatigue ... 813 Long–Term Behavior of Composites* ...
    (sci.med.cardiology)
  • Re: DURA-ACE with Di2 technology wins iF award
    ... Buncha impressionables and fashion victims gave the prize to the wrong ... electronically assisted *manual* shifting version of the Cyber Nexus ... "DURA-ACE with Di2 technology wins iF Product Design Award 2009 ... Shimano's electronic road racing components DURA-ACE with Di2 ...
    (rec.bicycles.tech)
  • DURA-ACE with Di2 technology wins iF award
    ... "DURA-ACE with Di2 technology wins iF Product Design Award 2009 ... Shimano's electronic road racing components DURA-ACE with Di2 ...
    (rec.bicycles.tech)
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