Wheel truing with dial indicators

Discussion in 'Cycling Equipment' started by Saltytri, Feb 16, 2003.

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  1. Saltytri

    Saltytri Guest

    I just put together a truing stand with dial indicators for radial and lateral truing. Also, a dish
    tool with a dial indicator. (No flames on this, please - I know that some will say that this level
    of precision is overkill but I like making things.) While Jobst's fine book suggests that dial
    indicators have some value, I haven't found any reference that tells me what level of truing and
    dish accuracy is considered acceptable. I don't have enough experience to know by look/feel/calipers
    when a wheel is considered good enough so I can't translate build quality by those more subjective
    standards into objective measurement criteria. What are reasonable targets in thousanths?
     
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  2. Jobst Brandt

    Jobst Brandt Guest

    anonymous writes timidly:

    > I just put together a truing stand with dial indicators for radial and lateral truing. Also, a
    > dish tool with a dial indicator. (No flames on this, please - I know that some will say that this
    > level of precision is overkill but I like making things.)

    > While Jobst's fine book suggests that dial indicators have some value, I haven't found any
    > reference that tells me what level of truing and dish accuracy is considered acceptable. I don't
    > have enough experience to know by look/feel/calipers when a wheel is considered good enough so I
    > can't translate build quality by those more subjective standards into objective measurement
    > criteria. What are reasonable targets in thousandths?

    Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005 is
    fine. Just remember that brake pads drag on rear wheels anyway with dual pivot brakes because their
    higher mechanical advantage demands lower brake pad clearance. For this reason many professional
    riders leave the rear QR open on long climbs and Campagnolo switched back to a single pivot 1:1
    ratio caliper for rear brakes.

    These are the criteria for trueness, aside from the need for uniform tension among spokes of the
    same side for rear wheels and all spokes for front wheels. It seems to me that if you are designing
    tools, the goal should already be known and the method of achieving that arrived upon from practice.
    Quantifying lateral and vertical trueness is one thing, but doing it so that it assists truing a
    wheel requires more than just that. It must be practical. Reading numbers may not be as useful to
    the experienced mechanic than watching an air gap between rim and gauge point grow and shrink when
    the wheel is rotated. This method has served well with good results for a long time.

    Jobst Brandt [email protected] Palo Alto CA
     
  3. in article a8%[email protected], [email protected] wrote:

    > Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
    > is fine.
    >
    What units are you using there?

    Shane Stanley
     
  4. Jobst Brandt

    Jobst Brandt Guest

    Shane Stanley writes:

    >> Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
    >> is fine.

    > What units are you using there?

    Oh how clever. What else? Did you perhaps think millimeters, nanometers, or Angstroms. This reminds
    me of Snap-on Tools changing their metric wrench markings to, for instance, to 10MM instead of 10,
    so the American will know it's not a 10inch end wrench, much less a 30inch on a large one. Lower
    case m's were not good enough either, while English sizes were not changed to show that they are in
    inches. I guess for some folks a 25x error is easy to make when measuring or selecting tools.

    Jobst Brandt [email protected] Palo Alto CA
     
  5. in article [email protected], [email protected] wrote:

    > Shane Stanley writes:
    >
    >>> Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
    >>> is fine.
    >>>
    >> What units are you using there?
    >>
    > Oh how clever.
    >
    It wasn't particularly meant to be, although I guess one could argue that being unsure and not
    asking would be dumb.

    > What else? Did you perhaps think millimeters, nanometers, or Angstroms.
    >
    I assumed inches, but I was wondering if the answer was none of these. The only other site I can
    find that mentions a value (admittedly not specifically for a new wheel) says 1/16th of an inch,
    which is more than 10 times 0.005 inches. Given the disparity, I thought it not unreasonable to
    check if the difference was one of units.

    > I guess for some folks a 25x error is easy to make when measuring or selecting tools.

    And I guess for some clever folks an error of judgment about a simple question is easy to make.

    Shane Stanley
     
  6. Saltytri <[email protected]> wrote:
    : I just put together a truing stand with dial indicators for radial and lateral truing. Also, a
    : dish tool with a dial indicator. (No flames on this, please - I know that some will say that this
    : level of precision is overkill but I like making things.) While Jobst's fine book suggests that
    : dial indicators have some value, I haven't found any reference that tells me what level of truing
    : and dish accuracy is considered acceptable. I don't have enough experience to know by
    : look/feel/calipers when a wheel is considered good enough so I can't translate build quality by
    : those more subjective standards into objective measurement criteria. What are reasonable targets
    : in thousanths?

    I aim for less than 1mm - 0.039" - which is pretty easy to achieve. I doubt there is any real
    benefit in a lower figure other than some kind of perverse satisfaction. Tyres are usually out of
    round to a greater extent anyway.

    I don't buy Jobst's version of brake pads rubbing on rims. Curiously, my single pivoted bike climbs
    just as easily as my dual pivoted one. Sounds like bicycle folklore.

    Cheerz, Lynzz
     
  7. <[email protected]> wrote:
    >Shane Stanley writes:
    >>>Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
    >>>is fine.
    >>What units are you using there?
    >Oh how clever. What else?

    Besides being snide, it'd be handy if you told us what it is that the units obviously are. .005in
    seems too little - turning one nipple 1/4 turn on a conventional 36-spoke wheel moves the rim
    laterally by more than an eighth of a millimeter, and you yourself say a 1/4 turn is the minimum
    necessary adjustment. .005cm is even smaller, and .005 meters is ridiculously large.

    So, no, it's not just pedantry. I have no idea what the units are here; and I thought exactly the
    same thing as Mr. Stanley on first reading your articles.
    --
    David Damerell <[email protected]> flcl?
     
  8. On 17 Feb 2003, David Damerell wrote:
    > <[email protected]> wrote:
    > >Shane Stanley writes:
    > >>>Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
    > >>>is fine.
    > >>What units are you using there?
    > >Oh how clever. What else?
    > Besides being snide, it'd be handy if you told us what it is that the units obviously are.
    .................
    > So, no, it's not just pedantry. I have no idea what the units are here; and I thought exactly the
    > same thing as Mr. Stanley on first reading your articles.

    Me too, in fact. Though I soon suspected you were only teasing about it. Were you really?

    Sergio Pisa
     
  9. Mikeyankee

    Mikeyankee Guest

    >lateral alignment between +-0.005 is fine

    Seems to be about twice what I can usually achieve (depends somewhat on spoke count and rim type),
    and I haven't had any problems with durability, brakes rubbing, etc. I'm satisfied to get the
    lateral trueness within .25 mm by eyeball. How does one get closer than that, especially as a slight
    waviness sets in as the wheel is brought up to final tension (e.g., ~120 kgF drive-side tension on a
    road wheel with 14/15 DB spokes, measured by Wheelsmith tensiometer)?

    Mike Yankee

    (Address is munged to thwart spammers. To reply, delete everything after "com".)
     
  10. David Ornee

    David Ornee Guest

    <[email protected]> wrote in message news:a8%[email protected]...
    > anonymous writes timidly:
    >
    > > I just put together a truing stand with dial indicators for radial and lateral truing. Also, a
    > > dish tool with a dial indicator. (No flames on this, please - I know that some will say that
    > > this level of precision is overkill but I like making things.)
    >
    > > While Jobst's fine book suggests that dial indicators have some value, I haven't found any
    > > reference that tells me what level of truing and dish accuracy is considered acceptable. I don't
    > > have enough experience to know by look/feel/calipers when a wheel is considered good enough so I
    > > can't translate build quality by those more subjective standards into objective measurement
    > > criteria. What are reasonable targets in thousandths?
    >
    > Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005 is
    > fine. Just remember that brake pads drag on rear wheels anyway with dual pivot brakes because
    > their higher mechanical advantage demands lower brake pad clearance. For this reason many
    > professional riders leave the rear QR open on long climbs and Campagnolo switched back to a single
    > pivot 1:1 ratio caliper for rear brakes.
    >
    > These are the criteria for trueness, aside from the need for uniform tension among spokes of the
    > same side for rear wheels and all spokes for front wheels. It seems to me that if you are
    > designing tools, the goal should already be known and the method of achieving that arrived upon
    > from practice. Quantifying lateral and vertical trueness is one thing, but doing it so that it
    > assists truing a wheel requires more than just that. It must be practical. Reading numbers may
    > not be as useful to the experienced mechanic than watching an air gap between rim and gauge point
    > grow and shrink when the wheel is rotated. This method has served well with good results for a
    > long time.
    >
    > Jobst Brandt [email protected] Palo Alto CA

    Lateral error should be <.5 mm I suggest you get a copy of Barnett's Chapter 17 on Wheel Truing. I
    think you will find that precision in tension balancing is more important than getting extremely
    precise truing. Spoke alignment, proper spoke tension, tension balancing, and stress relieving are
    all covered in Jobst's book. A quote from Wheelsmith's website at URL
    http://www.wheelsmith.com/page4.html bears repeating: "Wheelsmith's wheelbuilding philosophy
    emphasizes strength and durability, and the key is high, uniform spoke tension. Spoke tension is the
    most difficult and elusive aspect of wheelbuilding. It is the characteristic of the wheel most
    difficult to evaluate, yet the most critical to its performance. This approach to wheelbuilding,
    based on combining both art and science, and focusing on tension rather than cosmetic trueness, was
    pioneered by Wheelsmith and remains at the foundation of our process. Cosmetic trueness can actually
    come at the expense of a wheel's strength because it can result in unbalanced tension. So do not be
    misled by some builders' claims about trueness, because what really matters is not how true a wheel
    is now, but how true it is 1,000 miles from now."

    David Ornee, Western Springs, IL
     
  11. David Ornee <[email protected]> wrote:
    ><[email protected]> wrote in message
    [stuff]
    >>Jobst Brandt [email protected] Palo Alto CA
    >Spoke alignment, proper spoke tension, tension balancing, and stress relieving are all covered in
    >Jobst's book.

    I think you'll find the gentleman to whom you have replied knows what is in Jobst's book quite well.
    --
    David Damerell <[email protected]> flcl?
     
  12. [email protected] wrote:
    > Shane Stanley writes:
    >
    >>> Depending on what sort of brakes and pad clearance you use, lateral alignment between +-0.005
    >>> is fine.
    >
    >> What units are you using there?
    >
    > Oh how clever. What else? Did you perhaps think millimeters, nanometers, or Angstroms. This
    > reminds me of Snap-on Tools changing their metric wrench markings to, for instance, 10MM instead
    > of 10, so the American will know it's not a 10inch end wrench, much less a 30inch on a large one.
    > Lower case m's were not good enough either, while English sizes were not changed to show that
    > they are in inches. I guess for some folks a 25x error is easy to make when measuring or
    > selecting tools.
    >
    > Jobst Brandt [email protected] Palo Alto CA

    So you're actually saying that a +-5 mm lateral alignment is sufficient.

    --
    Replace the dots to reply

    Perre
     
  13. David Ornee

    David Ornee Guest

    "David Damerell" <[email protected]> wrote in message
    news:C5w*[email protected]...
    > David Ornee <[email protected]> wrote:
    > ><[email protected]> wrote in message
    > [stuff]
    > >>Jobst Brandt [email protected] Palo Alto CA
    > >Spoke alignment, proper spoke tension, tension balancing, and stress relieving are all covered in
    > >Jobst's book.
    >
    > I think you'll find the gentleman to whom you have replied knows what is in Jobst's book
    > quite well.
    > --
    > David Damerell <[email protected]> flcl?

    I was replying to the group in what I thought would be a helpful sequence. I apologize if my input
    was out of order or not useful to you.

    David Ornee, Western Springs, IL
     
  14. Lindsay Rowlands <[email protected]> wrote in message
    news:<[email protected]>...
    > Saltytri <[email protected]> wrote:
    > : I just put together a truing stand with dial indicators for radial and lateral truing. Also, a
    > : dish tool with a dial indicator. (No flames on this, please - I know that some will say that
    > : this level of precision is overkill but I like making things.) While Jobst's fine book suggests
    > : that dial indicators have some value, I haven't found any reference that tells me what level of
    > : truing and dish accuracy is considered acceptable. I don't have enough experience to know by
    > : look/feel/calipers when a wheel is considered good enough so I can't translate build quality by
    > : those more subjective standards into objective measurement criteria. What are reasonable targets
    > : in thousanths?
    >
    > I aim for less than 1mm - 0.039" - which is pretty easy to achieve. I doubt there is any real
    > benefit in a lower figure other than some kind of perverse satisfaction. Tyres are usually out of
    > round to a greater extent anyway.
    >
    > I don't buy Jobst's version of brake pads rubbing on rims. Curiously, my single pivoted bike
    > climbs just as easily as my dual pivoted one. Sounds like bicycle folklore.
    >
    > Cheerz, Lynzz

    I thought that the reason Campy went to single pivot rear was to save weight. After all, the rear
    brake does not provide much stopping power compared with the front. Further, locking up the rear is
    easy and potentially dangerous with high mechanical advantage calipers. So, the two-pivot rear
    caliper gives no real stopping advantage but exacts a weight penalty.

    Does anyone know why bikes are made with the right hand brake controlling the rear wheel? Most of us
    are right handed and would have better control if the right hand lever operated the front brake, in
    my opinion. But I digress.

    Regarding how true is true, I think it is a good question ‘cause I am interested to see the opinion
    of others. It seems as if ±0.005" is a good objective. A total swing of 0.01" easy to see without
    indicators, but the difference between 0.005 and 0.006" is impossible to know without dial
    indicators. I think I'll try to find some old feeler gauges or get some shim stock just to give me
    an idea how true my wheels are. While I do not think wheel wobble is terribly important as long as
    the brakes don't rub, now I'm curious to see if I can make measurements with simple tools. Why?
    Because it is a matter of pride to make wheels that are very, very true. Since unusual spoking
    patterns are of no real benefit, the skilled amateur can find satisfaction with careful selection of
    components and meticulous assembly as his accomplishments. I'd like to quantify (once will probably
    be enough for me) just how true my home-built wheels are.

    How bad is unacceptable? I do not think I'd worry about a set of wheels with more than ±0.005
    depending upon the circumstances. For example, I'd relax my standards for a used wheel with sticky
    spokes / nipples. As long as I can get even spoke tension, avoid brake rubbing, and make the rider
    happy, I'd be satisfied. Steve Shapiro
     
  15. A Muzi

    A Muzi Guest

    "Jobst Brandt">> >> Depending on what sort of brakes and pad clearance you use, lateral
    > >> alignment between +-0.005 is fine.

    > Shane Stanley writes (trolls??):
    > > What units are you using there?

    <[email protected]> wrote in message news:[email protected]...
    > Oh how clever. What else? Did you perhaps think millimeters, nanometers, or Angstroms. This
    > reminds me of Snap-on Tools changing their metric wrench markings to, for instance, to 10MM
    > instead of 10, so the American will know it's not a 10inch end wrench, much less a 30inch on a
    > large one. Lower case m's were not good enough either, while English sizes were not changed to
    > show that they are in inches. I guess for some folks a 25x error is easy to make when measuring or
    > selecting tools.

    Yes I was dismayed as well when SnapOn started with the redundant _capital_ "MM" markings.

    Every other brand of USA made wrench here is similarly marked ( although not all in capital
    letters). My VAR, Weinmann and Hozan just display the number.

    I just expected more of SnapOn, an otherwise quality product.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  16. Stu

    Stu Guest

    >Does anyone know why bikes are made with the right hand brake controlling the rear wheel? Most of
    >us are right handed and would have better control if the right hand lever operated the front brake,
    >in my opinion. But I digress.
    snip move to Australia, we use right hand front brake. as to the reason l have heard it has
    something to do with what side of the road you ride on, but as far as l know no one has figured
    out for sure why some drive on the right and some on the left so fell free to come up with your
    owe theory
     
  17. Matt O'Toole

    Matt O'Toole Guest

    "MikeYankee" <[email protected]> wrote in message
    news:[email protected]...

    > >lateral alignment between +-0.005 is fine
    >
    > Seems to be about twice what I can usually achieve
    (depends somewhat on spoke
    > count and rim type), and I haven't had any problems with
    durability, brakes
    > rubbing, etc. I'm satisfied to get the lateral trueness
    within .25 mm by
    > eyeball. How does one get closer than that, especially as
    a slight waviness
    > sets in as the wheel is brought up to final tension (e.g.,
    ~120 kgF drive-side
    > tension on a road wheel with 14/15 DB spokes, measured by
    Wheelsmith
    > tensiometer)?

    If the tension is even and the rim doesn't kiss the brake pads intermittently as it goes around,
    then it's good enough for me -- as it should be for anyone who isn't clinically
    obsessive-compulsive. If you ask me to quantify this level of straightness with a number, I can't
    tell you. I've never bothered to measure it because it's irrelevent.

    Dial, schmial.

    Matt O.
     
  18. Matt O'Toole

    Matt O'Toole Guest

    "stu" <[email protected]> wrote in message news:[email protected]...

    > >Does anyone know why bikes are made with the right hand
    brake
    > >controlling the rear wheel? Most of us are right handed
    and would
    > >have better control if the right hand lever operated the
    front brake,
    > >in my opinion. But I digress.

    > move to Australia, we use right hand front brake. as to
    the reason l have
    > heard it has something to do with what side of the road
    you ride on, but as
    > far as l know no one has figured out for sure why some
    drive on the right
    > and some on the left so fell free to come up with your owe
    theory

    This horse has been beaten to a pulp here. I beleive it's in the FAQ too. Please try a Google search
    rather than start up another discussion about it! Please, oh please!

    Matt O.
     
  19. Steve Shapiro wrote:
    >
    > Lindsay Rowlands <[email protected]> wrote in message
    > news:<[email protected]>...
    > > I aim for less than 1mm - 0.039" - which is pretty easy to achieve. I doubt there is any real
    > > benefit in a lower figure other than some kind of perverse satisfaction....
    >
    > Regarding how true is true, I think it is a good question ‘cause I am interested to see the
    > opinion of others. It seems as if ±0.005" is a good objective. A total swing of 0.01" easy to see
    > without indicators, but the difference between 0.005 and 0.006" is impossible to know without dial
    > indicators. I think I'll try to find some old feeler gauges or get some shim stock just to give me
    > an idea how true my wheels are.

    I just put a dial indicator on the wheels of a new bike we bought (decent quality Terry bike, maybe
    100 miles on it) and found 0.020" TIR. Looking at this visually, I'd probably be perfectly satisfied
    with this if I were building the wheel.

    I didn't put the dial indicator on the two bikes I ride the most, but it looks to me like they're at
    roughly 0.040" TIR. Like Lindsay, I'm satisfied with that. It would need to be much worse before I'd
    feel the need to straighten them. I should mention, though, that those bikes (my touring bike and my
    commuting bike) both have cantilever brakes, so dragging a super-sensitive double-pivot brake shoe
    isn't one of my concerns.

    Regarding Steve's statement: I'm not convinced "a total swing of 0.01"
    [is] easy to see without indicators." A machinist's six inch rule goes down to 0.01" resolution, and
    that's not real easy to read even with a workpiece that's sitting still. Maybe you can see
    0.01" on a rotating wheel - but I bet you can't see it from five feet away!

    --
    Frank Krygowski [email protected]
     
  20. Robin Hubert

    Robin Hubert Guest

    "stu" <[email protected]> wrote in message news:[email protected]...
    > >Does anyone know why bikes are made with the right hand brake controlling the rear wheel? Most of
    > >us are right handed and would have better control if the right hand lever operated the front
    > >brake, in my opinion. But I digress.
    > snip move to Australia, we use right hand front brake. as to the reason l have heard it has
    > something to do with what side of the road you ride on, but
    as
    > far as l know no one has figured out for sure why some drive on the right and some on the left so
    > fell free to come up with your owe theory
    >

    Doesn't this lead to awkward front brake cable routing?

    Robin Hubert
     
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