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  1. #1
    Senior Member mzeffex's Avatar
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    Cracked dura ace crank?

    I just picked this up used then realized this:

    The green I think is supposed to be there, the red not so sure. Pictured is where the crank arm enters the spider. It is kind of raised, so is it just forging?

    Last edited by mzeffex; 01-12-10 at 09:57 PM.
    Quote Originally Posted by rjones28 View Post
    Are they talking about spectators feeding the cyclists? You know, like don't feed the bears?

  2. #2
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    Get your money back if you can.

    Assuming you have some $$$ tied up in this, if you can't get your money back and want to be sure, run it by a machine shop and have them do a penetrating dye test.

  3. #3
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    I had a stronglight that came apart right there, it was on my fixed and I almost hit a car. Good thing I still had a break, it just took me a second to remember it was there, and to stop wondering why I was coasting. Mine didn't fall apart though, it just spins like a free wheel now. lol

  4. #4
    Senior Member mzeffex's Avatar
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    It's not cracked. It's part of the manufacturing process.
    Quote Originally Posted by rjones28 View Post
    Are they talking about spectators feeding the cyclists? You know, like don't feed the bears?

  5. #5
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    It looks more like flash then a crack. Flash is raised metal whereas a crack would not be. It's a normal result of the manufacturing process, resulting from a gap in the edge of the production tooling which allows excess metal to flow out a bit. Usually it's broken, polished or machined off later, but not always, especially in non-critical places or where they don't expect it to be visible in the finished assembly, like the back of a crank arm. Don't sweat it, enjoy your new cranks.
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  6. #6
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    Quote Originally Posted by mzeffex View Post
    It's not cracked. It's part of the manufacturing process.
    I don't agree, I think it's broken. I don't have a Dura Ace crank but I just inspected two 9-speed Ultegra cranks, two 8-speed 105's and a couple of old SR and Suguino cranks and NONE of these have any molding flash, forging marks or similar parting lines on either side of the spider/hub junction. The hub to spider transitions on all of these are completely smooth.

    I can't believe a Dura Ace crank would be less finely finished than these are so I have to believe yours is cracked.

    Don't use it.

  7. #7
    Unobtanium-Based Lifeform calamarichris's Avatar
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    Quote Originally Posted by HillRider View Post
    I don't agree, I think it's broken. I don't have a Dura Ace crank but I just inspected two 9-speed Ultegra cranks, two 8-speed 105's and a couple of old SR and Suguino cranks and NONE of these have any molding flash, forging marks or similar parting lines on either side of the spider/hub junction. The hub to spider transitions on all of these are completely smooth.

    I can't believe a Dura Ace crank would be less finely finished than these are so I have to believe yours is cracked.

    Don't use it.
    I disagree completely. The new Dura Ace (Hollowtech) is made with a different process than those earlier, solid cranks you're comparing it to. The crank is fine. Mine had it when brand-new. Shimano puts it on the nearly-invisible underside of the crank. True, the underside is not as pretty as those earlier cranks, but overall it's much, much (& much-much) lighter and stiffer.
    Quote Originally Posted by EvilWeasel View Post
    Well, if you are gonna carry a snapped frame all the way home. It might as well be light weight carbon fiber.

  8. #8
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    Quote Originally Posted by calamarichris View Post
    I disagree completely. The new Dura Ace (Hollowtech) is made with a different process than those earlier, solid cranks you're comparing it to. The crank is fine. Mine had it when brand-new. Shimano puts it on the nearly-invisible underside of the crank. True, the underside is not as pretty as those earlier cranks, but overall it's much, much (& much-much) lighter and stiffer.
    OK, I missed that it was a Hollowtech II crank. I was, as you noted, comparing it to square taper and Octalink cranks and they look nothing like the one in the picture.

  9. #9
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    The green areas look like casting marks. The red area looks like a crack. Get a 10x magnifying glass and look at the area. If it is a crack you will not be able to see the bottom of the area. Flashing or casting marks will be very obvious.

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