Cracked rim from truing wheel?

Discussion in 'Cycling Equipment' started by jojoma, Aug 17, 2009.

  1. jojoma

    jojoma New Member

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    I was truing my wheel and noticed a crack at one of the spokes. (See pic)
    Would this have most likely been caused by me tightening the spoke too much while truing the wheel. I am not very good at truing, admittedly. I'm just wondering how this crack happened??


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  2. alfeng

    alfeng Well-Known Member

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    SOMEONE over tightened the spoke.
     
  3. jojoma

    jojoma New Member

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    People keep telling me truing wheels is easy. Maybe it is, but this is the second rim I've cracked from apparently over-tightening spokes. So is it better to loosen the spokes from the opposite side of the rim, as opposed to tightening the out of true side of the rim?

    Any words to live by when truing?
     
  4. alfeng

    alfeng Well-Known Member

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    Well, it is not only better, but recommended that you loosen the two spokes on the on the side of the rim that is 'bulging' away from the centerline which flank the 'bulge' (for want of a better description) before you tighten the spokes on the 'hollow' side (again, for want of a better description).

    You could probably benefit from owning/borrowing a tensiometer.

    It is MUCH EASIER to true wheels if you know how to lace & true a wheel from scratch.
     
  5. artemidorus

    artemidorus New Member

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    As alfeng says, unless you are aiming to reduce the radius of a rim at any given point, you need to loosen one or two opposing spokes before you tighten any given spoke. If the spoke is already loose, then, of course, this rule doesn't apply.
     
  6. Peter@vecchios

    [email protected] New Member

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    When you true a wheel, sometimes you tighten and sometimes you loosen. It's not just about tightening things, whether they be nipples or nuts and bolts.

    Truing wheels isn't hard but it can be diffucult. Rims are designed to have a maximum tension. Without a tensionmeter, it's hard to determine if you are at, below or above that value.

    Couple of good books out tere about these sorts of things.

    Jobst Brandt's and Gerd Schraner's

    [ame=http://www.amazon.com/s/ref=nb_ss?url=search-alias%3Dstripbooks&field-keywords=Jobst&x=0&y=0]Amazon.com: Jobst: Books[/ame]

    [ame=http://www.amazon.com/s/ref=nb_ss?url=search-alias%3Dstripbooks&field-keywords=Art+of+wheelbuilding&x=11&y=15]Amazon.com: Art of wheelbuilding: Books[/ame]
     
  7. MikeD

    MikeD New Member

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    Fatigue failure. How many miles on the rim? I don't think your truing the rim had much to do with it. Overtensioned spokes can shorten a rim's life, though.
     
  8. artemidorus

    artemidorus New Member

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    Fatigue failure it may well be, but it happened at that spot because that spoke was too tight.
     
  9. curby

    curby New Member

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    I too would like to know the mileage of the rims you have cracked...

    Definitely begin addressing an out of true wheel by loosening, if the rim doesnt move back in the right direction after loosening a couple-few spokes then the rim is in bad shape. Still may be able to make it useable but disparity in spoke tension is the root of many a 'chronically goes out of true' wheel.

    good luck

    all's'miles

    curby
     
  10. vspa

    vspa Active Member

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    I don't know with pre-built wheels and all the new technology, but at my old LBS my friend always delivered me the trued wheels with the spokes as loosen as posible. When those wheels were too tightly trued it took one broken-spoke to ruin your ride, while a less tight wheel could still function with a couple of broken spokes,
     
  11. artemidorus

    artemidorus New Member

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    I have to disagree vehemently with any suggestion that the spokes should be looser rather than tighter. As I understand it, and definitely in my experience, the tighter the spokes, the more durable the wheel, as long as manufacturer's specifications for spoke tension are not exceeded. It is not tension that fatigues spokes, but rather fluctuations in tension, and a sloppy wheel allows a bigger proportional amplitude of tension cycling.
     
  12. gb93433

    gb93433 New Member

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    Spokes that are too loose will fail due to flexing too much. The degree of tightness depends on the material the spokes are made of and load they are under.

    I have been building wheels since 1971 and we used to put washers under the nipples in light tims. Some of the rims I rode would weighed as little as 200 grams. Others I rode on the track and road weighed 285 grams. I weighed 180 pounds at the time. Some of the rims were hollow with no filling. Others were wood or plastic filled.

    Rims can fail due to over tightening and hitting serious bumps or holes.
     
  13. vspa

    vspa Active Member

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    i wrote ... as possible..., i didn't want to mean " loose "
    the idea is to keep that factor in mind before you start truing the wheel tightening every spoke, instead of searching for a more balanced approach
     
  14. nonfeel

    nonfeel New Member

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    Nothing will
     
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