Assessing Wheel Build Quality and Rebuild Options

Discussion in 'Cycling Equipment' started by J. Matt, May 5, 2003.

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  1. J. Matt

    J. Matt Guest

    I've just purchased a set of new machine-built mountain bike wheels with the intention of rebuilding
    them before use. The spoke tension on the front wheel seems very low, while the tension on the rear
    wheel seems somewhat high. I'm assessing the tensions by comparing the tone of the spokes when
    plucked to a well-built wheel. The well-built wheel sounds a B2 on an electronic guitar tuner.

    During a brief stint working in a bike shop several years ago, the mechanics when unboxing a new
    bike would brace the wheel against their thighs and in a controlled fashion do a manuever using
    their hands and forearms that would seem like they were trying to taco the wheel. During this
    manuever, the wheel would often ping or creak. This, according to the mechanics, was a sign of a
    cheaply built wheel that needed attention. When I did this manuever to the wheelset I've just
    purchased, there was a good deal of creaking and pinging.

    My plan is to detension the spokes to the point where the threads just show, and then to loosely
    follow Sheldon Brown's instructions on his site from "Initial Tensioning" forward. The spokes seem
    to be flush against the hub right after the bend but I can't imagine anyone has gone by hand and
    bent them.

    I'm concerned about several things. First, if the spokes threads have been properly lubed. How can I
    tell, and if I use a very thin lube like ProLink, will it penetrate the threads without me having to
    totally undo the spoke?

    Also, since the tension seems high on the rear wheel, is there a chance the rim will be warped?
    Would I be better off riding the set until problems arise or is preventitive building preferable?

    Anything else I should be aware of? This will be my sixth build and while my wheels are never
    perfectly true, they have been incredibly durable.

    Thanks in advance

    John Matthew
     
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  2. Jobst Brandt

    Jobst Brandt Guest

    John Matthew writes:

    > I've just purchased a set of new machine-built mountain bike wheels with the intention of
    > rebuilding them before use. The spoke tension on the front wheel seems very low, while the tension
    > on the rear wheel seems somewhat high. I'm assessing the tensions by comparing the tone of the
    > spokes when plucked to a well-built wheel. The well-built wheel sounds a B2 on an electronic
    > guitar tuner.

    > During a brief stint working in a bike shop several years ago, the mechanics when unboxing a new
    > bike would brace the wheel against their thighs and in a controlled fashion do a maneuver using
    > their hands and forearms that would seem like they were trying to taco the wheel. During this
    > maneuver, the wheel would often ping or creak. This, according to the mechanics, was a sign of a
    > cheaply built wheel that needed attention. When I did this maneuver to the wheelset I've just
    > purchased, there was a good deal of creaking and pinging.

    You should probably build your own wheels or at least know what and why wheels respond to such
    treatments as they do. Your bicycle shop may have that book on their book shelf. The pinging is
    residual twist in spokes left by the last adjustment. Spokes are long torsion springs that wind up
    when the spoke nipple is turned. After final adjustments the spoke nipple should always be backed
    off to the no twist position, something that is easy to feel with practice.

    > My plan is to de-tension the spokes to the point where the threads just show, and then to loosely
    > follow Sheldon Brown's instructions on his site from "Initial Tensioning" forward. The spokes seem
    > to be flush against the hub right after the bend but I can't imagine anyone has gone by hand and
    > bent them.

    Don't do that. It has no benefit. On the other hand, just tightening each spoke about 1/2 turn while
    backing off about 1/8 turn after tightening would be a good approach. I say that because most wheels
    are not tight enough anyway. The backing off will get rid of the pings and then you need to stress
    relieve all the spokes. DON"T start over!

    > I'm concerned about several things. First, if the spokes threads have been properly lubed. How can
    > I tell, and if I use a very thin lube like ProLink, will it penetrate the threads without me
    > having to totally undo the spoke?

    The worst lubrication problem is usually that between nipple and rim joint. Oiling that friction
    is to allow the spoke nipples to rotate when tightening spokes. Try that primarily and use 30W
    motor oil.

    > Also, since the tension seems high on the rear wheel, is there a chance the rim will be warped?
    > Would I be better off riding the set until problems arise or is preventive building preferable?

    It may be high on the right side but the left will be low in comparison. Stress relieving will
    reveal whether tension is too high.

    > Anything else I should be aware of? This will be my sixth build and while my wheels are never
    > perfectly true, they have been incredibly durable.

    http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html

    Jobst Brandt [email protected] Palo Alto CA
     
  3. David Kunz

    David Kunz Guest

    J. Matt wrote:
    > I've just purchased a set of new machine-built mountain bike wheels with the intention of
    > rebuilding them before use. The spoke tension on the front wheel seems very low, while the tension
    > on the rear wheel seems somewhat high. I'm assessing the tensions by comparing the tone of the
    > spokes when plucked to a well-built wheel. The well-built wheel sounds a B2 on an electronic
    > guitar tuner.
    >
    > During a brief stint working in a bike shop several years ago, the mechanics when unboxing a new
    > bike would brace the wheel against their thighs and in a controlled fashion do a manuever using
    > their hands and forearms that would seem like they were trying to taco the wheel. During this
    > manuever, the wheel would often ping or creak. This, according to the mechanics, was a sign of a
    > cheaply built wheel that needed attention. When I did this manuever to the wheelset I've just
    > purchased, there was a good deal of creaking and pinging.
    >
    > My plan is to detension the spokes to the point where the threads just show, and then to loosely
    > follow Sheldon Brown's instructions on his site from "Initial Tensioning" forward. The spokes seem
    > to be flush against the hub right after the bend but I can't imagine anyone has gone by hand and
    > bent them.
    >
    > I'm concerned about several things. First, if the spokes threads have been properly lubed. How can
    > I tell, and if I use a very thin lube like ProLink, will it penetrate the threads without me
    > having to totally undo the spoke?
    >
    > Also, since the tension seems high on the rear wheel, is there a chance the rim will be warped?
    > Would I be better off riding the set until problems arise or is preventitive building preferable?
    >
    > Anything else I should be aware of? This will be my sixth build and while my wheels are never
    > perfectly true, they have been incredibly durable.
    >
    > Thanks in advance
    >
    > John Matthew

    The pinging is the spokes unwinding -- when you tighten the nipple, sometimes, the spoke itself also
    turns. This pinging is the spokes going back to neutral.

    I wouldn't undo the rims. I'd do 2 things.

    - Stress relieve. Take a screw driver and holding the business end in your hand, put the handle
    between spoke pairs and twist. This seats the spokes better and bends them at the elbows to lie
    better. They'll be less likely to break over time.

    - Balance the tension and possibly bring the tension up. Read Sheldon's site and the site on
    guessing spoke tension by pitch (I seem to remember a link on Sheldon't page). Find the tight
    spokes -- look for a nearby looser spoke or a balancing tight spoke on the other side. Loosen the
    tight spoke 1/4 turn and tighten the loose spoke 1/4 turn. Check true and adjust if you've shifted
    things out -- looking for tight and loose spokes near the out of true point to adjust. Sometimes,
    a spoke that is tighter or looser than it's neighbors and 3 or 4 away from the out of true spot
    can be adjusted to bring it in!

    Remember that the disc side in the front and the hub side in the rear will be tighter than the other
    side. Set the tension on that side and let dish set the tension on the other side (dish is side-side
    position -- between the brake pads if you have V brakes).

    I'm lazy and don't worry too much about spoke wrap. I usually do the taco thing every so often
    instead (unless I see or feel the winding/ unwinding of a stubborn spoke, then I work like the books
    say :)). But I also use brass nipples which are less prone to it than alloy nipples. If you're
    worried about spoke wrap, try wrapping a small piece of tape like a flag around the stubborn spokes
    -- then you put your turn in and then back-off to bring the flag back to it's neutral position.

    And, get yourself a decent spoke wrench. The ones for doing spot trail fix-ups are pitiful and will
    probably strip some of the nipples as you come up to full tension.

    David
     
  4. steel-<< I've just purchased a set of new machine-built mountain bike wheels with the intention of
    rebuilding them before use.

    Assume you mean retensioning, truing, rounding, dishing, stress relieving, not rebuilding...

    << I'm assessing the tensions by comparing the tone of the spokes when plucked to a
    well-built wheel.

    Same gauge??If not, this means nada...

    << This, according to the mechanics, was a sign of a cheaply built wheel that needed attention.
    When I did this manuever to the wheelset I've just purchased, there was a good deal of creaking
    and pinging.

    Lots of residual spoke windup-

    << Would I be better off riding the set until problems arise or is preventitive building preferable?

    No-if you ride it, you will bend the rim on a poorly built wheel, deforming it and then the tesnion
    will not be even...do what you are planning to do-before you ride them..

    Lube the nipps into the rim and the threads...

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  5. J. Matt

    J. Matt Guest

    Based on your thoughtful responses, I have more questions.

    First, I'm assuming the technique the poster wrote of involving a screwdriver is similiar to that
    posted on Sheldon Brown's site using a crank arm. I'm unclear on where exactly the object is
    inserted, and what it accomplishes.

    Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very
    uneven yet the wheel is still true. Two respondents recommended not detensioning the wheel first
    but it seems to me it would be easier to start from a consistent baseline with each spoke right
    at where the threads show rather than attempting to true an already true wheel with uneven and
    low spoke tension.

    On a side note, is there any reason to give new hubs (XT) new grease or is the quality and quantity
    generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.

    Thanks

    John Matthew
     
  6. steel-<< On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
    quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.

    I add grease to all new hubs and adjust after the build...

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  7. J. Matt

    J. Matt Guest

    [email protected] (J. Matt) wrote in message
    news:<[email protected]>...
    > Based on your thoughtful responses, I have more questions.
    >
    > First, I'm assuming the technique the poster wrote of involving a screwdriver is similiar to that
    > posted on Sheldon Brown's site using a crank arm. I'm unclear on where exactly the object is
    > inserted, and what it accomplishes.
    >
    > Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very uneven
    > yet the wheel is still true. Two respondents recommended not detensioning the wheel first but it
    > seems to me it would be easier to start from a consistent baseline with each spoke right at where
    > the threads show rather than attempting to true an already true wheel with uneven and low spoke
    > tension.
    >
    > On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
    > quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.
    >
    > Thanks
    >
    > John Matthew

    Anyone?
     
  8. David Kunz

    David Kunz Guest

    J. Matt wrote:
    > Based on your thoughtful responses, I have more questions.
    >
    > First, I'm assuming the technique the poster wrote of involving a screwdriver is similiar to that
    > posted on Sheldon Brown's site using a crank arm. I'm unclear on where exactly the object is
    > inserted, and what it accomplishes.

    My understanding (if I'm wrong, I'll get corrected :)). It bends the spokes to lie better at the hub
    and seats them better. You put it in between the spokes where they cross closest to the center of
    the wheel on the side closest to the rim. You twist the spokes apart.

    > Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very uneven
    > yet the wheel is still true. Two respondents recommended not detensioning the wheel first but it
    > seems to me it would be easier to start from a consistent baseline with each spoke right at where
    > the threads show rather than attempting to true an already true wheel with uneven and low spoke
    > tension.

    When you build a wheel, you do the tension balancing step as you bring it up to full tension. You
    don't just go around the rim adding (say)
    1/2 turn to all spokes (unless you're balanced and almost at tension). If you detension back to
    threads flush, you'll end doing a lot more work. One easy reason to understand is that not all of
    the spokes have exactly the same amount of threads or is precisely the same length -- so you're
    not any better off. And, even if they were, they'd have to be precisely the same diameter over
    their length also :).

    > On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
    > quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.

    Always.

    David
     
  9. David Kunz

    David Kunz Guest

    David Kunz wrote:
    > J. Matt wrote:
    >
    >> Based on your thoughtful responses, I have more questions. First, I'm assuming the technique the
    >> poster wrote of involving a screwdriver is similiar to that posted on Sheldon Brown's site using
    >> a crank arm. I'm unclear on where exactly the object is inserted, and what it accomplishes.
    >
    >
    > My understanding (if I'm wrong, I'll get corrected :)). It bends the spokes to lie better at the
    > hub and seats them better. You put it in between the spokes where they cross closest to the center
    > of the wheel on the side closest to the rim. You twist the spokes apart.

    I hate to correct my own posts -- what I meant was to put it just past the spoke crossing that's
    midway between the hub and the rim and twist them apart -- not gently.
    >
    >> Second, after relieving the residual spoke windup, the tension (as gauged by tone) is very uneven
    >> yet the wheel is still true. Two respondents recommended not detensioning the wheel first but it
    >> seems to me it would be easier to start from a consistent baseline with each spoke right at where
    >> the threads show rather than attempting to true an already true wheel with uneven and low spoke
    >> tension.
    >
    >
    > When you build a wheel, you do the tension balancing step as you bring it up to full tension. You
    > don't just go around the rim adding (say)
    > 1/2 turn to all spokes (unless you're balanced and almost at tension). If you detension back to
    > threads flush, you'll end doing a lot more work. One easy reason to understand is that not all
    > of the spokes have exactly the same amount of threads or is precisely the same length -- so
    > you're not any better off. And, even if they were, they'd have to be precisely the same diameter
    > over their length also :).
    >
    >> On a side note, is there any reason to give new hubs (XT) new grease or is the quality and
    >> quantity generally adequete? The hubs run a little rough, but I'm proficient in cone adjustment.
    >
    >
    > Always.
    >
    > David
     
  10. J. Matt wrote:
    >>
    >>> Based on your thoughtful responses, I have more questions. First, I'm assuming the technique the
    >>> poster wrote of involving a screwdriver is similiar to that posted on Sheldon Brown's site using
    >>> a crank arm. I'm unclear on where exactly the object is inserted, and what it accomplishes.

    David Kunz wrote:

    >> My understanding (if I'm wrong, I'll get corrected :)). It bends the spokes to lie better at the
    >> hub and seats them better. You put it in between the spokes where they cross closest to the
    >> center of the wheel on the side closest to the rim. You twist the spokes apart.
    >
    > I hate to correct my own posts -- what I meant was to put it just past the spoke crossing that's
    > midway between the hub and the rim and twist them apart -- not gently.

    The screwdriver technique resembles the old-crank technique, but they're actually rather different.

    The screwdriver is inserted between the innermost crossing and the hub flange, and is used primarily
    as a way to improve the "spoke line" so that the spokes, especially the heads-in ones, will lie
    close against the hub flange.

    I don't generally do this while building a wheel, but sometimes do when repairing a wheel that
    somebody else built. When I build a wheel myself, I do the spoke lining by hand. This is easy to do
    if you do it right after lacing the wheel, before applying any tension to the spokes.

    The thing I do with the old crank is primarily to stress relieve the spokes, as described by Jobst
    Brandt. I use this variant technique because I have thin-skinned, delicate hands, and using the
    specific technique he recommends hurts, if enough pressure is applied.

    I put the crank in outward from the outermost (laced) crossing, and I twist the spokes _together_
    not apart. A side effect of this is that the spokes acquire a slight bend where they lace past one
    another at the outermost cross, rather than the broad curve they start with.

    See: http://sheldonbrown.com/wheelbuild.html#seating

    Sheldon "Stress Relief" Brown +---------------------------------------------+
    | I have suffered from being misunderstood | but I would have suffered a hell of a lot | more if I
    | had been understood. | --Clarence Darrow |
    +---------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
    617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
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