wheel building - first attempt

Discussion in 'General Cycling' started by Adam Lea, Sep 4, 2011.

  1. Adam Lea

    Adam Lea Guest

    The front wheel rim was worn so decided to get a new one from the LBS
    (don't fancy a front rim blowout!!) and thought I would have a go at
    re-building the wheel myself. I've done the lacing part, I think I
    managed to get the spoke tension roughly uniform using the plucking
    test, put the wheel in the front fork and managed to get it sufficiently
    straight that it will spin freely with the brake blocks in their normal
    position. I've done the de-tensioning thing as well by putting the wheel
    on a table by its axle and pushing down on it. I still have a couple of
    questions though:

    1. There are a few really small wobbles when the wheel is spun, but they
    are so small it is difficult to tell exactly where they are because I
    can only see them if the wheel is spun quickly. Is it necessary to get
    the wheel trued absolutely perfect?

    2. How do I know if the spoke tension in general is correct? It feels
    tight, but I don't know how tight it needs to be. I'm a bit wary of
    overdoing it.

    3. Is there anything I have missed?
     
    Adam Lea, Sep 4, 2011
    #1
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  2. Adam Lea

    Phil Cook Guest

    Spin the wheel slowly past the brake blocks with one pushed to just make
    contact. Adjust the spokes so it doesn't make contact and repeat.
     
    Phil Cook, Sep 4, 2011
    #2
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  3. Adam Lea

    Rob Morley Guest

    Not perfect, as long as the wobbles aren't indicative of uneven
    tension. I always true by ear rather than eye - if you don't have a
    jig fix something to the fork (a reflector bracket can be good for
    this) adjust it very close to the rim and listen for rubbing. First take
    off the worst up-and-down movement, then side-to-side, repeat a couple
    of times.
    I've no idea how tight my wheels are - I just do it by feel, some
    people insist on using a tensiometer. You can check it feels no tighter
    than the drive side on the back wheel (assuming that's reasonably
    sound).
    Dish? Chances are a non-disk front wheel will be about right anyway.
     
    Rob Morley, Sep 4, 2011
    #3
  4. Adam Lea

    Tosspot Guest

    If it's straight enough not to notice it will do for government work. A
    pen or similar taped to a stay/fork will get the last mm or so off.
    I *know* I'm going to regret this but...it's pretty hard to over tension
    a wheel without it becoming pretty obvious[1]. Again a pen or similar
    to 'ping' the spokes will let you know if the tension is even, which is
    a more important attribute.
    De-stress the spokes while building and at the end. Also I usually do
    1/2 on 1/4 off to stop the spokes getting wound up too much and the end,
    but that may be just a pinch of salt over the shoulder but it makes me
    feel better!


    If you do this again, and you probably will, I've seen good efforts
    simply using an old front fork in a vice as a guide.

    [1] Nipples will start to round, the wheel will start to 'crisp', the
    effort turn a nipple will go *way* up.
     
    Tosspot, Sep 5, 2011
    #4
  5. Adam Lea

    Mike Causer Guest

    It's not absolutely necessary, just more satisfying. With a rigidly
    mounted pointer (even a pencil will do) you should be able to find the
    high/low points to within a spoke. A dial-gauge makes it even easier.

    Find a good wheel, pling the spokes then get the new one to the same
    pitch? [1]

    TBH, I go for minimum side and radial wobble, dishing OK to the eye
    and spokes in the same third of an octave.

    With a dial-gauge I can get the wobble to 2 thousandths of a inch
    (sorry, about the archaic units, but I bought the gauge nigh on 40
    years ago....). If doing a quick true-up 10 thou is OK.

    However the bike I bought this week needs serious work on the back
    wheel. Long spokes on the drive side, short spokes on the non-drive
    side. What does that mean class? Yes, the rim is *way* off the
    centreline. Wobble I can measure with a wooden ruler. How could
    anyone /do/ that?

    I don't think you're enjoying it enough. Getting it right is the
    pleasurable part. Go read "Zen and the Art of Motorcycle Maintenance"
    again. Persig must have been a good wheelbuilder.




    [1] Not as Madame Souza's wheel tuned to make a xylophone in
    Belleville Rendezvous. All of them close to the same, and a bit
    higher pitched than that was. A lot higher than the fridge tray...



    Mike
     
    Mike Causer, Sep 5, 2011
    #5
  6. Adam Lea

    Paul - xxx Guest

    'pling' is a technical term ... ;)
    LOL, +1 ... best part about my dial gauge is the lack of a backplate so
    I can't actually tell units .. as a comparator it's brilliant. Ohm and
    the magnetic baseplate is a god-send. ;)
    Another +1. Nothing more satisfying than starting out with a boxfull
    of bits and getting a properly working wheel out of it.
     
    Paul - xxx, Sep 5, 2011
    #6
  7. Adam Lea

    Rob Morley Guest

    Ah, Pringles. :) But are the nipples so cold they talk to you?
     
    Rob Morley, Sep 5, 2011
    #7
  8. Adam Lea

    kimble Guest

    In the absence of a proper truing stand, I find smallish cable ties
    (ideally bright yellow or similar colour) around the fork/frame can be
    more useful than brake blocks: Position them so the free end of the
    cable tie just touches the rim (and can be tweaked by rotating the tie
    around the tube slightly). Then either listen for rubbing, or watch the
    gap between the end of the cable tie and its reflection in the surface
    of the rim.


    Kim.
    --
     
    kimble, Sep 5, 2011
    #8
  9. Adam Lea

    Tosspot Guest

    That's really a very good idea!
     
    Tosspot, Sep 5, 2011
    #9
  10. Adam Lea

    Rob Morley Guest

    Starting out with a box full of bits and getting a new frame out of it?
    But yes, wheelbuilding can be very satisfying.
     
    Rob Morley, Sep 5, 2011
    #10
  11. Adam Lea

    Paul - xxx Guest

    I wish I Had the welding/brazing skills to build a frame .. ;)
     
    Paul - xxx, Sep 5, 2011
    #11
  12. Adam Lea

    Phil W Lee Guest

    Properly built wheels should be seen and not heard.
     
    Phil W Lee, Sep 5, 2011
    #12
  13. Adam Lea

    thirty-six Guest

    No. You have to make a judgement, although a new rim should be
    straight and stay there as the spokes are tensioned up, it can be
    difficult in a beginner's hands to keep i t straight.
    It's best to find out yourself by starting with the spokes at a
    relatively low tension and ride the wheel. As you go over quite minor
    bumps the nipples will rattle in the rim and the bike will want to
    drift down the road camber which you will have to continually steer
    against. The slack wheel will also make the bike feel soft when you
    get out of the saddle and will also steer poorly, being slow to
    respond. The general lack of lateral control of the wheel will
    discourage you from riding at speed or making any sudden steering
    movements. Without threadlock the nipples will vibrate and undo even
    more, making the ride even worse.

    Overtensioned spokes may show as buckling, tearouts or damaged
    nipples.
    Use some form of threadlock such as boiled linseed oil.
     
    thirty-six, Sep 5, 2011
    #13
  14. Adam Lea

    Rob Morley Guest

    No longer necessary - how about the carving and laminating skills to
    build a carbon monocoque? :)
     
    Rob Morley, Sep 5, 2011
    #14
  15. Adam Lea

    Adam Lea Guest

    Well, the problem is, part of me wants to learn the skill of doing it
    right, part of me wants to do it quickly to get the bike back on the
    road, part of me is not confident about my mechanical ability and is
    worried that the longer I fiddle with it, the more chance of messing it
    up and needing to shell out for a new rim and spokes, and part of me is
    concerned about getting it right to avoid the possibility of something
    catastrophic like the wheel collapsing or something.
     
    Adam Lea, Sep 5, 2011
    #15
  16. Adam Lea

    Adam Lea Guest

    How do I get the tension even when I am having to adjust tension in
    localised areas to true the wheel?
     
    Adam Lea, Sep 5, 2011
    #16
  17. I guess this might be true if you're riding an Ordinary with solid
    tyres, but it's never been an issue for me on any bike I've ever
    owned. Oh, and in the extremely unlikely event that I ever did need
    thread lock on a bike spoke, I would use Loctite, not oil. This is,
    after all, the Century of the Fruitbat.

    Guy
     
    Just zis Guy, you know?, Sep 6, 2011
    #17
  18. Adam Lea

    Rob Morley Guest

    Assuming the rim is round and true to start with, and the spokes
    identical, then getting the tension even and the wheel round and true
    should be pretty much the same thing. Just tightening all the
    spokes so they're level with the bottom of the slots in the nipples is
    usually a good start. However a stiff rim will make uneven tension
    harder to spot in terms of run-out, because it better resists the
    spokes' efforts to pull it out of shape, so despite the wheel running
    true some of the spokes may have substantially higher or lower tensions
    resulting in the likelihood of early failure. But if you get the
    overall tension about right, and have balanced up the spokes
    effectively to reasonably true the wheel, then pinging the spokes
    should confirm that none is particularly higher or lower pitched than
    the others.
     
    Rob Morley, Sep 6, 2011
    #18
  19. Adam Lea

    kimble Guest

    They're the No.1 roadside bicycle botching tool :)

    While I usually carry a few substantial (releasable) black cable ties
    for general-purpose botching, I keep a couple of little bright yellow
    ones in the touring kit for this reason. Combined with a head torch
    (and spoke key, of course) you can true a wheel pretty much anywhere.


    Kim.
    --
     
    kimble, Sep 6, 2011
    #19
  20. Adam Lea

    Tosspot Guest

    What he said, get it right at the beginning and it all falls into place.
    However, in my rather limited experience, round rims are rare, so there
    is often some variation in ping, but what you don't want is
    ping-ping-pong! Someone mentioned it up there --^, but if you can find
    a wheel you know is good, a pen over the spokes will give you some idea
    of the ping variation.

    I wouldn't stress over it too much, it's a first attempt, it will almost
    certainly be fine and if it isn't, well, just unlace it and do it again!
    Keep an eye on the lateral to see how long, if ever, it needs truing
    again, and ping the spokes when bored to see if any are unwinding.

    It all sounds quite complicated, but you're not trying to build the
    perfect wheel, just an acceptable wheel, and you've probably already
    managed that. In any event, subsequent builds (there will be more...)
    will improve technique/patience/tonal appreciation...
     
    Tosspot, Sep 6, 2011
    #20
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