Tensioning spokes by "tone"

[[email protected]]

On 13 Aug 2004 21:37:48 -0500, Jim Smith
<[email protected]> wrote:

>Weisse Luft <[email protected]> writes:
>
>> [email protected] Wrote:
>> > On Fri, 13 Aug 2004 20:47:24 GMT,
>> > [email protected] wrote:
>> >
>> > >[email protected] writes:
>> > >
>> > >> It is indeed humorous that we squabble about these things.
>> > >
>> > >> But no, I don't think that the fellows who have posted that they
>> > >> mark their spokes to observe twist are joking.
>> > >
>> > >> If spokes do indeed twist (everyone seems to agree that they do),
>> > >> then a line drawn down the untwisted spoke ought to reveal it. I
>> > >> haven't tried it (yet), but I expect that it's as much fun as using
>> > >> a tensiometer.
>> > >
>> > >> Elsewhere, Jobst Brandt has mentioned attaching post-it markers to
>> > >> spokes to demonstrate twist:
>> > >
>> > >> http://tinyurl.com/25l2c
>> > >
>> > >> In that post, "sued" is a truly unfortunate typo for "used."
>> > >
>> > >The post-it is a dynamic display of twist and not a means of
>> > >untwisting spokes. If you think you can readily see a helix with a
>> > >1/8 to 1/4 twist on a spoke 300mm long then you have more acute
>> > >eyesight than I. As I mentioned, lines on a barber pole make a full
>> > >revolution on a large diameter with a helix angle of about 45 degrees.
>> > >Helix angle on a 300mm long spoke is less than one degree, sued or
>> > used.
>> > >
>> > >Jobst Brandt
>> > >[email protected]
>> >
>> > Dear Jobst,
>> >
>> > Perhaps the people who like to draw lines on spokes have
>> > sufficiently acute vision to notice that the line has moved
>> > at the bottom 1/4 to 1/8 of a turn?
>> >
>> > It's been suggested in this thread that a mark near the
>> > bottom is enough to show the twist.
>> >
>> > Carl Fogel
>> On a well-lit work bench, I can clearly see the black Sharpie marker
>> line on my spokes. I know Jobst doesn't use Revolution spokes so his
>> 1/4-1/2 turn is valid for 14/15 or 15/16 spokes.
>>
>> I use Revolutions exclusively. And on the drive side rear, the Sharpie
>> marking gives me 100% noise free truing, not that I have had to do it in
>> a while. Drawing a thin, straight line on the spoke is easy. The felt
>> tip has a larger diameter hub which I use to guide the side of the felt
>> tip along the spoke. With light pressure and a new pen, the line is
>> very thin, even on the 1.5 mm section. It only takes seconds to do the
>> entire wheel from nip to crossing.
>>
>why is it necessary to mark the entire length of the spoke rather than
>just a single mark near the nipple?
>

Dear Jim,

Maybe the line at the non-twisted hub-end of the spoke makes
it a little easier to check where the line on the twisted
nipple-end of the spoke should be?

If Weisse's line is fairly straight and if Jobst is right
about the amount of twist, the two ends may end up
mismatched by 1/4 to 1/8th of a turn, 45 to 90 degrees.

The long line along the length of the spoke might be
unnecessary if there's a single mark at the nipple and some
corresponding mark on the rim (marking the nipple wouldn't
work).

Jobst's no-marking method may work just as well.

All these methods sound like reasonable attempts to deal
with reducing spoke twist. Absolute perfection would require
marking and some sort of cunning strain gauge--and wouldn't
be worth it. Imagine trying to align the top and bottom of a
shaft 300 mm long and 2 mm or less wide to within 1 degree.

Carl Fogel

 

[[email protected]]

Jim Smith writes:

> Why is it necessary to mark the entire length of the spoke rather
> than just a single mark near the nipple?

Because much of this talk is theoretical and impractical. That this
is done by anyone who builds more than a wheel or two on occasion is
hard to believe. As I said, it is interesting to demonstrate windup
by sticking a small Post-it on the spoke near the nipple but it is by
no means a reasonable way of truing a wheel, nor is marking spokes.
Just visualize (or mark a spoke) to understand how imprecise such a
technique is, both applying a definitively narrow and accurate mark
and detecting its rotation.

Jobst Brandt
[email protected]

 

[Jim Adney]

On Fri, 13 Aug 2004 20:47:24 GMT [email protected]
wrote:

>The post-it is a dynamic display of twist and not a means of
>untwisting spokes. If you think you can readily see a helix with a
>1/8 to 1/4 twist on a spoke 300mm long then you have more acute
>eyesight than I. As I mentioned, lines on a barber pole make a full
>revolution on a large diameter with a helix angle of about 45 degrees.
>Helix angle on a 300mm long spoke is less than one degree, sued or used.

I seem to recall that years ago it was rather easy to watch Torrington
spokes twist, because they seemed to show a kind of grain which was
actually drawing marks from the dies the spokes were made from. I
don't think this was at all hard to see.

I'll take your word for the fact that it only amounts to 1 degree, but
it's easy to see that the line has worked its way around the spoke.
It's the 45 degrees that's easy to notice, not the 1 degree.

-
-----------------------------------------------
Jim Adney [email protected]
Madison, WI 53711 USA
-----------------------------------------------

 

[Trevor Jeffrey]

Trevor Jeffrey wrote in message ...
>
>Weisse Luft wrote in message ...
>>
>>Yes, a single black mark would work but I have yet to find a permanent
>>marker that will adhere to shiny spokes Making a thin black line is
>>redundant.
>>
>permanent marker not required. Use valve marker.
>
>Trevor
>
>
Berol 79 valve marker, it is permanent type.

 

[[email protected]]

Jim Adney writes:

>> The post-it is a dynamic display of twist and not a means of
>> untwisting spokes. If you think you can readily see a helix with a
>> 1/8 to 1/4 twist on a spoke 300mm long then you have more acute
>> eyesight than I. As I mentioned, lines on a barber pole make a
>> full revolution on a large diameter with a helix angle of about 45
>> degrees. Helix angle on a 300mm long spoke is less than one
>> degree, sued or used.

> I seem to recall that years ago it was rather easy to watch
> Torrington spokes twist, because they seemed to show a kind of grain
> which was actually drawing marks from the dies the spokes were made
> from. I don't think this was at all hard to see.

That is correct, but these grooves were about 0.1mm wide at most and
straight, neither of which is reasonably possible with a manual marker.

> I'll take your word for the fact that it only amounts to 1 degree, but
> it's easy to see that the line has worked its way around the spoke.
> It's the 45 degrees that's easy to notice, not the 1 degree.

Not if it is a hand made felt marker or brushed on white stripe.

Jobst Brandt
[email protected]

 

[Evan Evans]

[email protected] wrote in message news:<[email protected]>...
> On 13 Aug 2004 19:04:50 -0700, [email protected] (Evan
> Evans) wrote:
>
> [snip]
>
> >I still need help! We are marking the spoke to see the amount of twist
> >in the spoke. Why do we need to know the amount of twist? I normaly
> >just true the wheel until it's round & sraight. I am still missing
> >something.
>
> Dear Evan,
>
> The idea is to end up with the wheel well trued and
> tensioned, but with no twist in the spokes to later unscrew
> and goof things up.
>
> If you true and tension the wheel in a stand without taking
> into account the twisting of the spokes under high tension,
> the spokes will start to untwist when you ride down the road
> on the wheel and your weight causes the spokes to lose
> tension as they roll under the hub and randomly untwist.
>
> The "ping" noises heard by many riders riding on new wheels
> are generally thought to be twisted spokes abruptly
> untwisting. Shortly afterward, the riders may notice their
> beautfully trued wheels are no longer true.
>
> Carl Fogel

OHHHH-k! Ihave never done that with the marker. Does it work? I always
have to adjust my wheels after a brake-in period & always assumed
thats just life.

 

[[email protected]]

On 14 Aug 2004 12:17:07 -0700, [email protected] (Evan
Evans) wrote:

>[email protected] wrote in message news:<[email protected]>...
>> On 13 Aug 2004 19:04:50 -0700, [email protected] (Evan
>> Evans) wrote:
>>
>> [snip]
>>
>> >I still need help! We are marking the spoke to see the amount of twist
>> >in the spoke. Why do we need to know the amount of twist? I normaly
>> >just true the wheel until it's round & sraight. I am still missing
>> >something.
>>
>> Dear Evan,
>>
>> The idea is to end up with the wheel well trued and
>> tensioned, but with no twist in the spokes to later unscrew
>> and goof things up.
>>
>> If you true and tension the wheel in a stand without taking
>> into account the twisting of the spokes under high tension,
>> the spokes will start to untwist when you ride down the road
>> on the wheel and your weight causes the spokes to lose
>> tension as they roll under the hub and randomly untwist.
>>
>> The "ping" noises heard by many riders riding on new wheels
>> are generally thought to be twisted spokes abruptly
>> untwisting. Shortly afterward, the riders may notice their
>> beautfully trued wheels are no longer true.
>>
>> Carl Fogel
>
>OHHHH-k! Ihave never done that with the marker. Does it work? I always
>have to adjust my wheels after a brake-in period & always assumed
>thats just life.

Dear Evan,

I sometimes have trouble remembering which way to turn the
spoke wrench, but several posters in this thread have
indicated that they use various marker methods with success.

Others prefer Jobst Brandt's over-shoot-and-back-off method,
which involves deliberately tightening the nipple a bit more
than needed for truing or tensioning (now the spoke is
twisted or wound-up) and then loosening it back down
slightly to the right tension or truing (which untwists the
spoke).

Quite possibly the marker enthusiasts are using exactly the
same overshoot-and-back-off method and simply like the
confirmation that the twist has been eliminated. How much to
overshoot and how much to back off is likely to be a
perennial question (as well as how much it matters).

I expect that both groups build good wheels, partly because
of their wonderful techniques and partly because they have
such wonderful parts:

"It appears that the better spokes now available would have
made the discovery of many of the concepts of this book more
difficult for lack of failure data. I am grateful in
retrospect for the poor durability of earlier spokes. They
operated so near their limits that durability was
significantly altered by the techniques that I have
outlined."

--Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993,
p.124

Eleven years later, it's likely that spokes and other parts
are even better, a common trend in machinery. I just
finished mowing the lawn and was again struck by how much
nicer a cheap 2004 lawn mower is than the 1980 model that it
replaced--safer, smoother, quieter, easier to start, simpler
to operate, and much better at cutting and mulching the
grass. And in inflation-adjusted dollars, it cost only about
half as much.

Carl Fogel

 

[Trevor Jeffrey]

[email protected] wrote in message ...
>
>I don't see how you can get a wheel adequately tight without such
>methods, spokes not withstanding the required torque even when well
>lubricated. My experience with 1.5mm diameter spokes was with Berg
>and Radaelli spokes and I shot a few of these into the ceiling. Hence
>the warning in "the Bicycle Wheel" to not be in the line of fire when
>tightening spokes. I built 24 spoke track wheels and had the same
>experience with 1.8-1.6 conventional DT spokes.

Open your eyes and use the method I use, that of shaping the spoke at the
crossing point so as it does not act as a spring, but a restraining member
of the wheel.

Trevor

 

[Sheldon Brown]

Carl Fogel wrote:
> Others prefer Jobst Brandt's over-shoot-and-back-off method,
> which involves deliberately tightening the nipple a bit more
> than needed for truing or tensioning (now the spoke is
> twisted or wound-up) and then loosening it back down
> slightly to the right tension or truing (which untwists the
> spoke).

This is not specifically "Jobst Brandt's" method. It is, and has been,
the method used by _every_ competent wheelbuilder.

> Quite possibly the marker enthusiasts are using exactly the
> same overshoot-and-back-off method and simply like the
> confirmation that the twist has been eliminated.

Yes, that's the idea. Sort of like "training wheels" for beginner
wheelbuilders. It's not clear that training wheels are the best way to
learn to balance a bike, either.

This is one of the reasons I like Wheelsmith Aero spokes for
applications that call for light, thin spokes, because they give a good
visual/tactile indication of when the torsion has been removed.

> How much to
> overshoot and how much to back off is likely to be a
> perennial question (as well as how much it matters).

No, that is not in question at all. The amount to back off is whatever
amount is needed to eliminate the twist in the spoke.

The specific amount will vary from spoke to spoke, depending on the
thread diameter, wire diameter, length, and the amount of friction in
the threads.

The last item, thread friction, will itself vary according to the
quality of the thread machining, spoke tension, nipple alignment and
what lubricant is used.

> "It appears that the better spokes now available would have
> made the discovery of many of the concepts of this book more
> difficult for lack of failure data. I am grateful in
> retrospect for the poor durability of earlier spokes. They
> operated so near their limits that durability was
> significantly altered by the techniques that I have
> outlined."
>
> --Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993,
> p.124
>
> Eleven years later, it's likely that spokes and other parts
> are even better, a common trend in machinery. I just
> finished mowing the lawn and was again struck by how much
> nicer a cheap 2004 lawn mower is than the 1980 model that it
> replaced--safer, smoother, quieter, easier to start, simpler
> to operate, and much better at cutting and mulching the
> grass.

A lawn mower is much more complicated than a spoke. There was a quantum
jump in spoke quality when DT spokes and Edco nipples appeared on the
market, sometime in the late '70s, I believe.

Since then there have not been any important improvements in spokes that
I know of.

Sheldon "Punctuated Equlibrium" Brown
+---------------------------------------------------------------+
| Let us begin by committing ourselves to the truth - |
| to see it like it is, and tell it like it is - |
| to find the truth, to speak the truth, and live the truth. |
| --Richard M. Nixon, Accepting nomination in 1968 |
+---------------------------------------------------------------+
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

 

[[email protected]]

On Sat, 14 Aug 2004 16:35:13 -0400, Sheldon Brown
<[email protected]> wrote:

>Carl Fogel wrote:
>> Others prefer Jobst Brandt's over-shoot-and-back-off method,
>> which involves deliberately tightening the nipple a bit more
>> than needed for truing or tensioning (now the spoke is
>> twisted or wound-up) and then loosening it back down
>> slightly to the right tension or truing (which untwists the
>> spoke).
>
>This is not specifically "Jobst Brandt's" method. It is, and has been,
>the method used by _every_ competent wheelbuilder.
>
>> Quite possibly the marker enthusiasts are using exactly the
>> same overshoot-and-back-off method and simply like the
>> confirmation that the twist has been eliminated.
>
>Yes, that's the idea. Sort of like "training wheels" for beginner
>wheelbuilders .It'snotclearthattrainingwheelsarethebestwayto
>learn to balance a bike, either.
>
>This is one of the reasons I like Wheelsmith Aero spokes for
>applications that call for light, thin spokes, because they give a good
>visual/tactile indication of when the torsion has been removed.
>
>> How much to
>> overshoot and how much to back off is likely to be a
>> perennial question (as well as how much it matters).
>
>No, that is not in question at all. The amount to back off is whatever
>amount is needed to eliminate the twist in the spoke.
>
>The specific amount will vary from spoke to spoke, depending on the
>thread diameter, wire diameter, length, and the amount of friction in
>the threads.
>
>The last item, thread friction, will itself vary according to the
>quality of the thread machining, spoke tension, nipple alignment and
>what lubricant is used.
>
>> "It appears that the better spokes now available would have
>> made the discovery of many of the concepts of this book more
>> difficult for lack of failure data. I am grateful in
>> retrospect for the poor durability of earlier spokes. They
>> operated so near their limits that durability was
>> significantly altered by the techniques that I have
>> outlined."
>>
>> --Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993,
>> p.124
>>
>> Eleven years later, it's likely that spokes and other parts
>> are even better, a common trend in machinery. I just
>> finished mowing the lawn and was again struck by how much
>> nicer a cheap 2004 lawn mower is than the 1980 model that it
>> replaced--safer, smoother, quieter, easier to start, simpler
>> to operate, and much better at cutting and mulching the
>> grass.
>
>A lawn mower is much more complicated than a spoke. There was a quantum
>jump in spoke quality when DT spokes and Edco nipples appeared on the
>market, sometime in the late '70s, I believe.
>
>Since then there have not been any important improvements in spokes that
>I know of.
>
>Sheldon "Punctuated Equlibrium" Brown
>+---------------------------------------------------------------+
>| Let us begin by committing ourselves to the truth - |
>| to see it like it is, and tell it like it is - |
>| to find the truth, to speak the truth, and live the truth. |
>| --Richard M. Nixon, Accepting nomination in 1968 |
>+---------------------------------------------------------------+
> 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

Dear Sheldon,

You prefer WheelSmith Aero spokes, but I assume that these
are bladed spokes whose shape puts all the marking methods
mentioned in this thread to shame and makes any twist
obvious even to mechanics as inept as I am.

The question that I had in mind was how can Evan tell when
he's backed off enough to eliminate twist on ordinary round
spokes.

As for the spoke improvement, Jobst published his book in
1981.

A second edition appeared in 1988 with no mention of spoke
improvement.

Only twelve years later in the third edition of 1993 did
Jobst add the comment about better spokes being available.

This led me to believe that Jobst saw significant spoke
improvements between 1981 and 1993, which seems to be well
after the last major improvement that you mention in the
late 1970's.

We may not actually disagree. You may be thinking of almost
dramatic ("important") improvements in which an obviously
changed spoke put last year's model to shame, something
along the lines of Gould's punctuated equilibrium.

I'm thinking of much smaller cumulative improvements, more
along the lines of Linneaus and natura non facit saltum,
even though engineering can obviously make leaps still
debated in evolutionary circles.

I gather that there have been improvements in the raw
material, the manufacturing process, and the design details
of even of items as apparently simple as spokes.

A 1% improvement in steel quality per year, an annual 1%
reduction in manufacturing nicks, or a 1% change in elbow
length or angle are all invisible to the public, but they
can add up to an impressive change over two decades.

The Japanese are not the only manufacturers who follow Dr.
Deming's principles of reducing variation and constant
slight improvements.

Carl Fogel

 

[[email protected]]

Trevor Jeffrey writes:

>> I don't see how you can get a wheel adequately tight without such
>> methods, spokes not withstanding the required torque even when well
>> lubricated. My experience with 1.5mm diameter spokes was with Berg
>> and Radaelli spokes and I shot a few of these into the ceiling.
>> Hence the warning in "the Bicycle Wheel" to not be in the line of
>> fire when tightening spokes. I built 24 spoke track wheels and had
>> the same experience with 1.8-1.6 conventional DT spokes.

> Open your eyes and use the method I use, that of shaping the spoke
> at the crossing point so as it does not act as a spring, but a
> restraining member of the wheel.

Would you be kind enough to expand on that. I don't understand how
you do that. The torsional strength of a 1.5mm diameter spoke is too
weak to withstand tightening torque at any length. Tightening torque
from the spoke nipple is uniform throughout the spoke, length has no
bearing on that. It is not windup as such that is the problem but
spoke rupture from the combination of tension and torque.

However, please explain your technique of "shaping the spoke",
"restraining" and "acting as a spring". This is entirely new to me.

Jobst Brandt
[email protected]

 

[Nubo]

[email protected] wrote:

>The post-it is a dynamic display of twist and not a means of
>untwisting spokes. If you think you can readily see a helix with a
>1/8 to 1/4 twist on a spoke 300mm long then you have more acute
>eyesight than I. As I mentioned, lines on a barber pole make a full
>revolution on a large diameter with a helix angle of about 45 degrees.
>Helix angle on a 300mm long spoke is less than one degree, sued or used.
>
>
I 've used the marker method on most occasions when I've built a wheel.
I've only built wheels for my own use, so this is infrequent - say a
wheel every other year on average.

Due to the frequency, I trust the visual cue more than my "feel" with
the wrench.

It's ironic that you seem to have as much difficulty with the marker
method as I have with the "feel" method!

I find that twist is very easy to notice with a marker line. It's easy
enough to draw a relatively straight line down the spoke. With a
wide-tipped marker a groove readily forms in the tip which makes this
easy. Simply keep the marker perpendicular to the plane of the wheel
and slide it down. The eye can see a deviation from 90 degrees to
within a couple of degrees, so keeping the marker perpendicular is easy
enough. A marker with a firm tip will allow pressure variations without
much change in the application. The result is a very straight and
uniform line, though I think that absolute uniformity (thickness) may
not even be all that critical.

It only takes a minute or two to stripe all of the spokes. I find that
striping from the cross to the nipple is sufficient. With the right
kind of marker, removal is as easy as rubbing down with a rag. Even
permanent markers will yield to a bit of rubbing alcohol. I usually use
a red artists marker - easier to see than black and a little less
tenacious than the ubiquitous "marks-a-lot" black permanent marker.

As far as being hard to notice a twist visually, my experience is the
exact opposite. A difference of even a few degrees between the crossing
point and the nipple stands out clearly. Again, part of the reason is
that the stripe is originally aligned perpendicular to the wheel plane.
I take it that by "helix angle" you're describing the angle from
sighting down the spoke on-end. I guess that *would* be a tiny angle,
but that isn't what catches the eye. Rather, imagine 2 half-spokes
welded to a normal spoke (mid-point and again proximal to the nipple),
such that the half-spokes are oriented perpendicular to the wheel plane.
Now imagine a 5-degree twist imparted to the spoke. It would be very
obvious that the twist has occurred. The mind's eye can see that effect
by the orientation of the marked stripe; imagining the angle at which
the center of the stripe is "pointing" outward at any point along the
spoke. Checking the stripe requires looking at the wheel from the side
(line of sight perpendicular to the plane rather than parallel).

This is a long-winded description of something that's really easy to do.
The effect may or may not be obvious to the user; for me it is.

I use it as a validation for "feel" in backing off the twist. Tht is, I
do some work, and then double-check against the line. Very often the
two are in agreement. Sometimes the line will tell me I've missed a bit
of twist and then by working it out I notice, again, a good correlation
between feel and sight.

If you can do it all by feel, more power to you. If you're like me and
build or true only rarely, striping with a marker may make things
easier. It only adds a few minutes to the process so it's easy enough
to try it out. If the stripe and your feel always agree then you've got
good feel and don't need it.

>
>

 

[Jim Adney]

On Sat, 14 Aug 2004 21:16:31 +0100 "Trevor Jeffrey"
<[email protected]> wrote:

>
>[email protected] wrote in message ...
>>
>>I don't see how you can get a wheel adequately tight without such
>>methods, spokes not withstanding the required torque even when well
>>lubricated. My experience with 1.5mm diameter spokes was with Berg
>>and Radaelli spokes and I shot a few of these into the ceiling. Hence
>>the warning in "the Bicycle Wheel" to not be in the line of fire when
>>tightening spokes. I built 24 spoke track wheels and had the same
>>experience with 1.8-1.6 conventional DT spokes.
>
>Open your eyes and use the method I use, that of shaping the spoke at the
>crossing point so as it does not act as a spring, but a restraining member
>of the wheel.
>
>Trevor
>
>

-
-----------------------------------------------
Jim Adney [email protected]
Madison, WI 53711 USA
-----------------------------------------------

 

[Jim Adney]

On Sat, 14 Aug 2004 21:16:31 +0100 "Trevor Jeffrey"
<[email protected]> wrote:

>Open your eyes and use the method I use, that of shaping the spoke at the
>crossing point so as it does not act as a spring, but a restraining member
>of the wheel.

Huh?

-
-----------------------------------------------
Jim Adney [email protected]
Madison, WI 53711 USA
-----------------------------------------------

 

[Jim Adney]

On Sat, 14 Aug 2004 18:54:18 GMT [email protected]
wrote:

>Jim Adney writes:
>
>>> The post-it is a dynamic display of twist and not a means of
>>> untwisting spokes. If you think you can readily see a helix with a
>>> 1/8 to 1/4 twist on a spoke 300mm long then you have more acute
>>> eyesight than I. As I mentioned, lines on a barber pole make a
>>> full revolution on a large diameter with a helix angle of about 45
>>> degrees. Helix angle on a 300mm long spoke is less than one
>>> degree, sued or used.
>
>> I seem to recall that years ago it was rather easy to watch
>> Torrington spokes twist, because they seemed to show a kind of grain
>> which was actually drawing marks from the dies the spokes were made
>> from. I don't think this was at all hard to see.
>
>That is correct, but these grooves were about 0.1mm wide at most and
>straight, neither of which is reasonably possible with a manual marker.

If I were to do this I would not bother to even try to make long
straight marks. A short mark in a known position would be sufficient,
like a dot facing directly left, for example.

>> I'll take your word for the fact that it only amounts to 1 degree, but
>> it's easy to see that the line has worked its way around the spoke.
>> It's the 45 degrees that's easy to notice, not the 1 degree.
>
>Not if it is a hand made felt marker or brushed on white stripe.

A mark that covers 90 degrees of the spoke can still be easily noticed
to have moved 45 degrees. I don't see any problem with that.

OTOH, I totally agree that it's much easier to just feel the twist and
back off to the neutral torsion point when actually building a wheel.

-
-----------------------------------------------
Jim Adney [email protected]
Madison, WI 53711 USA
-----------------------------------------------

 

[Trevor Jeffrey]

[email protected] wrote in message ...
>Trevor Jeffrey writes:
>> Open your eyes and use the method I use, that of shaping the spoke
>> at the crossing point so as it does not act as a spring, but a
>> restraining member of the wheel.
>
>Would you be kind enough to expand on that. I don't understand how
>you do that. The torsional strength of a 1.5mm diameter spoke is too
>weak to withstand tightening torque at any length. Tightening torque
>from the spoke nipple is uniform throughout the spoke, length has no
>bearing on that. It is not windup as such that is the problem but
>spoke rupture from the combination of tension and torque.
>
>However, please explain your technique of "shaping the spoke",
>"restraining" and "acting as a spring". This is entirely new to me.
>

You should pay more attention, back of the dinner queue for you.

My build method involves shaping the spoke at the crossing point so that it
takes a direct line from hub to crossing point and from crossing point to
rim whether it is loose or infinitely tight. This ensures that the
differential loading between a pair of spokes keeps the lateral movement at
the crossing to a minimum (within the graphs that have been produced notice
the narrow angle over which a spoke has to move as it varies between high
and low values, much less than the angle between a spoke and its partner).
This then reduces angular displacement of the spoke where it joins with the
hub (caused by the differential loading between a pair of spokes) and so
minimises its affect on fatigue failure at the hub juncture. It is the side
to side bending of the spokes which are the primary cause of fatigue failure
of spokes not shaped during construction of a wheel.

A wheel built without shaping at the x-ing require an infinite amount of
tension in the spokes to enable them to come close to being straight. This
is why you have found high tension in spokes reduces fatigue failure of
those spokes. The over tensioning also helps in the respect of shaping the
x-ing so will also help. I have gone one step further and specifically
shaped the spokes at the x-ing point so that spokes are straight from hub to
x-ing and from x-ing to rim. They deviate little whether extremely tight or
just tight enough to prevent loose spokes under service conditions.

Lace wheel in standard manner. tension so spokes assume final angle. Mark
x-ing point on pair of spokes. Remove nipples on this pair. Bend spokes
across each other so there angular displacement is equal and appropriate for
their final resting position. Install nipples with driver, checking that
the spokes are touching each other and the nipples are centred and slack in
the rim holes. Check the angles with a straight edge and a gauge, little
finger nail may do. Tighten back to initial tension. Work round wheel
doing all the other pairs. When the wheel is tightened up for service it
will be seen upon inspection that movement at the crossing points is
minimal. It will be found that truing up becomes very easy, with each
nipple movement placing an obvious related movement at the rim.

Without shaping, the spoke curves around its partner and so maintains this
curve unless infinite spoke tension is used. Steel is always curved to make
springs. Hence you have a spring. This is what makes a wheel sloppy. Take
a spoke out of one of your wheels and examine how straight it is. You will
find it to be curved, and so it is acting as a spring, maintaining similar
tension on contraction and expansion. a straight spoke will increasingly
resist expansion as the strain increases. Only minimal tension is required,
not maximal because the spoke is already straight.

So here we have a wheel which does not require exceedingly high tensions to
make it function and so it is unlikely to snap a spoke or pop a nipple. I
use linseed oil to prevent the nipple rattling out of adjustment with
vibration during gross overload of the wheel.

Trevor

 

[Alex Rodriguez]

In article <[email protected]>, [email protected]
says...

>You prefer WheelSmith Aero spokes, but I assume that these
>are bladed spokes whose shape puts all the marking methods
>mentioned in this thread to shame and makes any twist
>obvious even to mechanics as inept as I am.

The wheelsmith spokes are not bladed, they are oval. they don't require
you to slot your hub either.
--------------
Alex

 

[David Damerell]

Trevor Jeffrey <[email protected]> wrote:
[bending crossing points]
>doing all the other pairs. When the wheel is tightened up for service it
>will be seen upon inspection that movement at the crossing points is
>minimal. It will be found that truing up becomes very easy, with each
>nipple movement placing an obvious related movement at the rim.

Why is it not, then, found that truing radially spoked wheels is equally
"very easy"? They have no crossing points.
--
David Damerell <[email protected]> Distortion Field!

 

[Qui si parla Campagnolo]

trevor-<< I have gone one step further and specifically
shaped the spokes at the x-ing point so that spokes are straight from hub to
x-ing and from x-ing to rim. >><BR><BR>
<< tension so spokes assume final angle. Mark
x-ing point on pair of spokes. Remove nipples on this pair. Bend spokes
across each other so there angular displacement is equal and appropriate for
their final resting position. >><BR><BR>


Gee, I guess the 5000 or so wheels I have built have all been wrong.

This method above is silly, not required.

trevor-<< Without shaping, the spoke curves around its partner and so maintains
this
curve unless infinite spoke tension is used. Steel is always curved to make
springs. Hence you have a spring. This is what makes a wheel sloppy
>><BR><BR>


'sloppy wheels.?? Ridiculous.

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

 

[[email protected]]

Trevor Jeffrey <[email protected]> writes:

>>> Open your eyes and use the method I use, that of shaping the spoke
>>> at the crossing point so as it does not act as a spring, but a
>>> restraining member of the wheel.

>> Would you be kind enough to expand on that. I don't understand how
>> you do that. The torsional strength of a 1.5mm diameter spoke is
>> too weak to withstand tightening torque at any length. Tightening
>> torque from the spoke nipple is uniform throughout the spoke,
>> length has no bearing on that. It is not windup as such that is
>> the problem but spoke rupture from the combination of tension and
>> torque.

>> However, please explain your technique of "shaping the spoke",
>> "restraining" and "acting as a spring". This is entirely new to
>> me.

> You should pay more attention, back of the dinner queue for you.

> My build method involves shaping the spoke at the crossing point so
> that it takes a direct line from hub to crossing point and from
> crossing point to rim whether it is loose or infinitely tight. This
> ensures that the differential loading between a pair of spokes keeps
> the lateral movement at the crossing to a minimum (within the graphs
> that have been produced notice the narrow angle over which a spoke
> has to move as it varies between high and low values, much less than
> the angle between a spoke and its partner). This then reduces
> angular displacement of the spoke where it joins with the hub
> (caused by the differential loading between a pair of spokes) and so
> minimises its affect on fatigue failure at the hub juncture. It is
> the side to side bending of the spokes which are the primary cause
> of fatigue failure of spokes not shaped during construction of a
> wheel.

How does putting a kink in the spoke at the crossing change lateral
motion at that point as spoke tension varies from radial loading.
Spokes do not fail at the crossing but rather in the thread and
elbow... or at the threads and spoke head for elbowless spokes. I am
sure that if you drew an exaggerated view of the crossing you would
find that whether spokes cross with an angular bend rather than a
radiused one, there is no difference in lateral displacement with
load.

Besides this consideration, you should be aware that many bicycle do
not interleave spokes at the crossing and still suffer spoke failures
at the ends. Also as I mentioned, there are many spoke patterns today
that have no spokes of one flange crossing each other.

> A wheel built without shaping at the x-ing require an infinite amount of
> tension in the spokes to enable them to come close to being straight. This
> is why you have found high tension in spokes reduces fatigue failure of
> those spokes.

I made no such finding. That is a bit of myth and lore that gets
retold in this forum from time to time. I suspect you have not read
"the Bicycle Wheel" other than the cover and take your cues from
hearsay or you wouldn't make the claims you do.

> The over tensioning also helps in the respect of shaping the x-ing
> so will also help. I have gone one step further and specifically
> shaped the spokes at the x-ing point so that spokes are straight
> from hub to x-ing and from x-ing to rim. They deviate little
> whether extremely tight or just tight enough to prevent loose spokes
> under service conditions.

That is also untrue. Removing a spoke from a highly tensioned wheel
after many thousand miles shows it to be straight and without more
than a fretting mark at the point of interleaving with its neighbor.

> Lace wheel in standard manner. tension so spokes assume final
> angle. Mark x-ing point on pair of spokes. Remove nipples on this
> pair. Bend spokes across each other so there angular displacement
> is equal and appropriate for their final resting position. Install
> nipples with driver, checking that the spokes are touching each
> other and the nipples are centred and slack in the rim holes. Check
> the angles with a straight edge and a gauge, little finger nail may
> do. Tighten back to initial tension. Work round wheel doing all
> the other pairs. When the wheel is tightened up for service it will
> be seen upon inspection that movement at the crossing points is
> minimal. It will be found that truing up becomes very easy, with
> each nipple movement placing an obvious related movement at the rim.

Thanks for clarifying your method. Just the same I believe your are
imagining the beneficial results because spoke crossing movement is
not dependent on the shape of the intersection but rather where the
contact resides between spoke ends and the change in tension under
loading. I am certain that you did not measure the displacement
because that measurement can be computed and it is not influenced by
spoke shape. Shape is a parameter that doesn't appear in the
calculation.

> Without shaping, the spoke curves around its partner and so
> maintains this curve unless infinite spoke tension is used. Steel
> is always curved to make springs. Hence you have a spring. This is
> what makes a wheel sloppy. Take a spoke out of one of your wheels
> and examine how straight it is. You will find it to be curved, and
> so it is acting as a spring, maintaining similar tension on
> contraction and expansion. a straight spoke will increasingly
> resist expansion as the strain increases. Only minimal tension is
> required, not maximal because the spoke is already straight.

You are incorrect, the spokes are straight or at least do not reveal
where they crossed other than a fretting witness mark.

> So here we have a wheel which does not require exceedingly high
> tensions to make it function and so it is unlikely to snap a spoke
> or pop a nipple. I use linseed oil to prevent the nipple rattling
> out of adjustment with vibration during gross overload of the wheel.

I think your perception of a wheel are inaccurate. Why tension the
spokes at any more than to remove slack if tension is not a practical
function in the tensioned wire wheel? In fact using an average wheel
in a tandem generally does not work long because loads are
systematically near twice as great as on a single.

Jobst Brandt
[email protected]