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  1. #1
    Senior Member mkadam68's Avatar
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    Broken Spoke Nipple Head

    Have some new-ish wheels with about 1,000 mi on them. Carbon tubular, 50mm. On Friday, I popped a spoke nipple, NDS. LBS fixed it up that night. I rode about 50-miles each day, Sat, Sun & Mon (total of 150-miles) and popped another nipple head about 5-miles from home.

    Near as I can figure, it must be

    1. Pressure from below the nipple pushing up on the head, or
    2. Twisting pressure that "unscrews" the head, or
    3. Both.



    I can't figure out what would be doing this. Anybody ever seen this or have any ideas?

    IMAGE_CC9757E4-973C-4497-A5C1-3AB1EC752973.JPG

    (Cross-posted in Mechanics forum, but put here for more eyeballs.)

    Visit The C-Blog : the blog about cycling.

  2. #2
    Senior Member halfspeed's Avatar
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    Happened to me with Soul C4.0s. I replaced all the spokes with longer ones that reached the end of the nipple and all of the nipples. It has been fine since. Also, make sure it was laced correctly in the first place. If the spokes were laced so that they went through the holes intended for the opposite side of the wheel, that could be a problem as well.
    Telemachus has, indeed, sneezed.

  3. #3
    Senior Member mkadam68's Avatar
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    Just spoke with my LBS (who fixed the 1st one; a different LBS built the wheel). He said the nipples were alloy, and perhaps should have been brass for a guy my size.

    I might just have him re-lace the wheel using appropriate nipples (I'll talk to him about your experience with longer spokes, too, thnx).

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  4. #4
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    You have to re lace that whole wheel, sure you have low spoke count right?

    If you got the wheel hand made then the builder might have put spokes too short based in how the nipple snapped. If you take the tubular off the rim, look inside of the hole. The spoke threads should be flush or over the spoke head. Based in the picture at least that one was seat too low, then the nipple has to work too much and they simply snaps.

    I do my own wheels, and no matter if the nipples are alloy, Ti, carbon or even made of alien buggers. If the wheel is built right the nipples will last 20 or 30 years w/o any problem. Again, based in the picture looks like the spokes are too short.

    The reason the second spoke snapped is because that spoke had to work for the one that broke initially that same day. So for sure you will get other nipples to snap later on, that's how it is with low count wheelsets. One spoke snaps then the other ones are ready to go sooner than later.

    If you got the wheel from china or something, I would advice you to check the tension because probably the tension is going up and down from spoke to spoke, another reason to see the problem. I have seen this issue even in descent wheels like eastons or velocity for example. Had to lose them and start truing them again to bring the tension to something more even than what it was before. To do his is simple, just touch the spokes and feel the tension... if you clearly feel differences in tension then the wheel came bad from where ever u got it and you found maybe the main reason of the problem.

    1st thing, check the spokes as i said before. then check the tension by hand (is easy). If you have a combination of both or just the 1st one that the spokes are not all the way up or flushed to the spoke head then I would advice you to get new spokes (longer ones obviously) with new heads and relace that wheel.

    Well you got the problem already, i was you i would relace the wheel again with new spokes and heads, hope you know how to do it because LBS will charge you a lot for this job. If you were in my area i would fix you the wheels for free.

    Check the other wheel just in case too.

  5. #5
    Senior Member mkadam68's Avatar
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    Thanks, ultraman. Looking at the picture, the spoke definitely did not thread all the way into the head of the nipple. So, that looks like the problem.

    Yeah, 32h wheel. I had a LBS build the wheel. I supplied separate rim & hub to them.

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  6. #6
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    32H??? thats not that low count... the guys put the wrong spokes in there. I would advice you to do the job yourself... know how to true wheels is always a good skill to have, specially with carbon rims and stuff because if something happens will be you to blame, not somebody else.

    Put the hub and rim dimensions in a spoke calculator and see which are the spokes you need, or just get longer ones and by eye calculate the new spoke lenght. Then start replacing them one by one.

    Learn to true wheels

  7. #7
    Senior Member halfspeed's Avatar
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    Quote Originally Posted by mkadam68 View Post
    Thanks, ultraman. Looking at the picture, the spoke definitely did not thread all the way into the head of the nipple. So, that looks like the problem.

    Yeah, 32h wheel. I had a LBS build the wheel. I supplied separate rim & hub to them.
    Ultraman is right on everything. But also don't forget to check that your wheelbuilder laced it correctly. It may not seem so, but spoke holes are offset a bit in the rim. If the rim is laced incorrectly, a spoke will run from the hub flange to a spoke hole offset to the opposite side. That'll put extra stress on a nipple's shoulders and could cause it to shear.
    Telemachus has, indeed, sneezed.

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