Truing wheels

Discussion in 'Mountain Bikes' started by worm72, Sep 10, 2004.

  1. worm72

    worm72 New Member

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    I have to readjust my spokes every time I ride, but this is a different problem. My rear wheel has a warp that I can't seem to correct. All the spokes that I need to tighten are already too tight and all the spokes I need to loosen are already too loose. I tried to adjust it for out-of- round, but that didn't help. Does anyone have any suggestioons?
    Thanks, worm
     
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  2. gruppo

    gruppo New Member

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    Time to seek professional help?
     
  3. Juba

    Juba New Member

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    One of two things has happened. Your rim is warped beyond the ability for the spokes to keep it in true, or your overall spoke tension is so poor that your spokes are not aligning the rim properly (causing certain spokes to have overcompensated and some undercompensating).

    Either way, you are most likely looking at a new wheel rebuild. Possibly new spokes, nipples and a new rim. Some one who is more skilled at wheel truing might be able to loosen off all your spokes, and retention them, which is pretty close to rebuilding, minus the lacing and pre-streching steps.

    Cheers,
    Juba
     
  4. dabac

    dabac Well-Known Member

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    Juba mentioned overtensioning, but there might be something else going on. Did something happen immediately before the warp appeared? A bad landing, collision, someone kicking your bike (vandalism on bikes left locked outside does happen)? Any of these things can lead to a lasting deformity on the rim, and if the rim isn't true in itself there's no way to get a true and equally tensioned wheel.

    I've fixed a wheel like that by disassembling it and straigthening the rim, and then rebuilding the wheel again with new spokes. But its quite time consuming, so this wouldn't be a sensible option for a LBS. If they do the job, get a new rim instead.
     
  5. worm72

    worm72 New Member

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    I have been replacing spokes for a long time. I usually 'had' (knock on wood) 1 or 2 broken spokes every time I ride. I didn't realize the spokes on some wheels are diffent lengths for the inside and outside of the wheel. Do you think this may be the problem? My bike is a 1998 Trek 830. Do you know if the spokes are different lengths for this Model?
    thanks, worm
     
  6. dabac

    dabac Well-Known Member

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    Then there's something badly wrong. Probably a completely messed-up build, or some sort of maintenance abuse.
    Front wheels with rim brakes use the same length, rears and disc brake wheels might not. There's a good spoke length calculator at : http://www.dtswiss.com/spokescalc/Calculator.aspx Enter your bike's specifics and it'll tell you what to use.
    Not directly. If you've got the same lace at both sides the difference is usually only 2 mm, and the nipples can frequently be adjusted to cover for that. But if you're using the wrong spoke length you might run out of threads before the spokes have reached the right tension (ands it's spoke tension - not nipple torque that's important) - and that can set you up for future failures. But assuming you're not amazingly wrong in spoke tension and the spokes break at the elbow - then the length isn't to blame. If the spokes are ripped from the nipples - then the length is definitely to blame, especially if you're using brass nipples. [/QUOTE] My bike is a 1998 Trek 830. Do you know if the spokes are different lengths for this Model? [/QUOTE] They probably are, check the spoke calc to make sure.
     
  7. worm72

    worm72 New Member

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    The spoke calculator is in German and my browser will not translate it. :)
     
  8. dabac

    dabac Well-Known Member

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    Sorry about that. Head back to the main site (dtswiss.com or something like that), choose language and navigate down to spoke calc again.
     
  9. socalfeltrider

    socalfeltrider New Member

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    take the wheel off the bike, hold it opposite the bad area, pick it way up above your head and with one fast motion slam it all the way to the ground (try to hit the tire and not the rim)!!! It should then be 90% where it needs to be, true it from there and you should find that the spoke tension is close to correct. This is probably only going to hold it true until the next "big hit" then you can re-build or replace.
    -hope that helps...
     
  10. Juba

    Juba New Member

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    What socalfeltrider has suggested is useful if you taco a wheel in the middle of a ride, you can slam it into shape so it will get you home. And when you get home, replace the rim/spokes.

    This is not a suggestable solution for mechanically repairing a wheel. Slamming a wheel like this is going to violently stretch/fatigue your spokes, fatigue your spoke nipples, fatigue your hub flange, lots of ugly stuff. I certainly would not advise riding a wheel that has been repaired like this unless it was simply the only option to get me back to my Jeep or my house.

    If you have a rim that is warped enough that you cannot get it back into true by properly loosening/tightening the spokes, or if you are constantly snapping spokes (which is a sign that the wheel was poorly built) bite the bullet, buy a new rim, buy new spokes/nipples and build a new wheel. Or get someone that knows how to build a wheel build it for you.

    Cheers,
    Juba
     
  11. socalfeltrider

    socalfeltrider New Member

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    Ah ha! Juba again.... If you re-read my post, I am not suggesting a "solution for mechanically repairing a wheel" I have said that that is the way to straighten it until the "next big hit", then it will be time to replace. I have to again laugh at your reply, this time about "violently stretch/fatigue your spokes, fatigue your spoke nipples, fatigue your hub flange, lots of ugly stuff." How do you suppose the original damage occured in the first place, solely from JRA (or, I was "just riding along") the damage to the wheel has been done, and if you ride your bike you must know that your wheels encounter SO MUCH more abuse than what I have suggested he do to straighten it out to ride on. Think about how old your current wheelset is and how many off-road miles you have on them, how many times during each ride do you put your wheels where you did not mean to and think "oh that hurt!" Give me a break pal, I weigh 190lbs and ride my bike hard (and respect it and take care of it) and I know my wheels have seen ten times the force applied to them when I am cranking up a hill or landing off of a 12 foot drop to a sketchy transition, so please think before you say that by hitting your wheel on the ground you are putting your wheel through a "violent" demolition!! I do the same thing to my wheels every day with all 190lbs of weight behind me, and again, I am relaying this to another person(s) on this forum with the forethought that they have common sense and do not take a 250lbs muscle-head to grab the wheel and smash it into the ground, the idea is to manipulate it back into it's shape.
     
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