Dave Ornee writes:
Dave, please look at the test below. This is how a series of
citations should look so that the progression of dialog can be
followed. I am responding to your last posting that is marked ">"
below. Also, for contractions like (didn't), please use ('😉 instead
of (?). ("😉 is generally used for quotations as well. Try it. I've
fixed these in this text.
Quoted message said:Quoted message said:Spokes have only tension, there are no radial, lateral and
torsional forces, and as I just pointed out, spokes don't move in
the flange and never again see a tension even nearly as high as
stress relieving.
Quoted message said:I am not arguing the size of the forces compared to stress
relieving. I am also not just talking about the force(s) in the
spoke; but the forces on the hub.
Yes, that is my question. From where do these forces come and how do
they affect the spoke-flange interface?
Quoted message said:Quoted message said:Quoted message said:If you take a wheel that is just built following your "book" and
then disassemble it; you will see some of the "spoke alignment
improvement" shape on the spoke surrounding the elbow and some
small amount of deforming of the areas in and around the spoke
flange hole. If you take the same wheel after it has been ridden
for 1,000s of miles you will see further deformation of
both... and if you haven't corrected the spoke tension during that
time/distance, you will find that the spokes have slackened.
Quoted message said:Quoted message said:I don't believe you have ever seen a comparison between a newly
built wheel and the same wheel used, in which such changes can or
have been determined. I have take apart enough wheels to know that
this is untrue... but it is what the purveyors of the method
visualize and want you to believe. Just think of all the lectures
we used to hear on the benefits of tying and soldering that were
given by "known experts" and people who built durable wheels.
Quoted message said:I have taken apart a few wheels, built by a few different builders,
and made the comparisons. What I saw was more deformation of the
spoke holes and more deformation of the spokes. Yes, I looked
before riding them and after riding them.
Quoted message said:What do you mean by purveyors of the method visualize?
I am not thinking about lectures of anyone.
Purveyors=: People who advise hammering on spoke heads to prevent
spoke movement.
Quoted message said:Quoted message said:Quoted message said:Not every spoke & hub have the same relative dimensions, so the
amount of change can also vary be amounts that would make a
significant difference in the resulting slackening. One of
differing dimensions if DT Spokes in original, Revision 1, and
Revision 2 having the difference of length amounting to 0.85 mm.
Quoted message said:Quoted message said:So? What does this have to do with seating the heads? That might
be an argument for washers for too long an elbow.
Quoted message said:Yes, I think that washers are a good idea, especially when the spoke
head to elbow distance is greater than the thickness of the hub
flange at the spoke hole. The longer the section of unsupported
distance from flange to elbow, the longer the moment arm is to act
on that segment of the spoke.
So again, what does "seating" spoke heads have to do with elbow length?
Quoted message said:Quoted message said:Quoted message said:I have seen such movement that I attribute to this from examining
other builder's wheels.
Quoted message said:Quoted message said:Certainly not your own. [I said in jest from the way you said that.]
Quoted message said:Thanks for that vote of confidence. I am still interested in
learning and that is one reason I read your book and why I read this
group's information.
Quoted message said:Quoted message said:How did you "see" such motion and how do you know that it occurred?
Are you talking about wheels with loose spokes?
Quoted message said:As I stated before, I have taken apart wheels that were newly built
to see what the hubs and spokes looked like. I put them back
together as they were and road them.
I still do not see how you could "see" that spokes had been moving.
Can you explain that?
Quoted message said:After ~10,000 miles I measured and found reduced spoke tension, and
then took them apart again and noticed that the hub holes were more
distorted and the spokes had also distorted more. I therefore
conclude that there must have been some movement of the spokes. If
the spokes didn't move, how else could there have been more
distortion in the spoke holes and further bending in the spokes?
I take it you removed the spokes from the hub. Is that correct?
Spokes have a die flash, a small ridge made by the split conical die
in which the head is formed by a single blow. With time the die sharp
edges wear off so that a gap develops on the closure edged and these
cause a raised ridge under the spoke head. Dies should be replaced
before this ridge becomes more than a vestige on the spoke.
Spoke elbows are subsequently bent onto the spoke with no orientation
with respect to head forming so the flash can lie in any orientation.
If you take spokes out of the hum, this is one problem they have.
They make a new mark in the flange. However, you should probably
avoid re-using spokes removed from a wheel if you can avoid it because
once tensioned, spoke line improved and stress relieved, spokes have a
unique shape and home location in the hub that is difficult to achieve
if the spoke is reused.
Again, what mechanism and method do you visualize for spoke movement?
Quoted message said:Since I have been riding for a little over 50 years, I have ridden
on quite a few wheels, and until the last few years they were not
wheels I built.
Then you ought to have had plenty of experience with spoke failures.
Quoted message said:Quoted message said:Quoted message said:Some builders were mistakenly attributing the movement to the
spoke/nipple interface and unwinding. Those builders then applied
red Loctite to the threads of the spokes to keep them from moving.
Quoted message said:Quoted message said:Quoted message said:However, the spoke was moving at the hub end and still slackening.
Quoted message said:Quoted message said:I think you'll have to describe the model by which spokes move in
the hub without ever going slack. What force is moving them and in
which direction.
Quoted message said:They moved in the direction which is the same as you show in the
modifying the spoke elbows? in your section describing steel hubs
and further the hub holes take on a more distorted look than your
illustration of the plain hole hubs.
Modifying the spoke line is a manual process to prevent spoke flexing.
This does not make the spoke move in the flange but rather overlays a
constant bending moment on spoke tension, thereby accelerating
fatigue. This is important to the spoke but does not affect the
flange hole.
Quoted message said:Braking forces, pedaling forces, and riding over bumps adds some
tension to some spokes at some times. I grant you that these
forces, taken one at a time, are not as great as the force in stress
relieving, but forces from pedaling, braking, and hitting bumps
occur many times while riding thousands of miles.
So? All this occurs within elastic limits of spokes and flanges.
Because tension is far lower than during stress relieving, this cannot
have a plastic effect on either spokes or hub and therefore, no
subsequent setting can occur.
Quoted message said:Quoted message said:Quoted message said:I am sure they weren't moving as the end was in the exact same
location inside the nipple and it was impossible to turn the
nipple off the spoke with a DT spoke wrench and as much force as I
could apply.
Quoted message said:Quoted message said:You mean "as much force as the spoke would withstand". I can twist
off a spoke with a slot jaw spoke wrench.
Quoted message said:The wheel that I worked on had red Loctite on spoke threads, but I
at first didn't know it was there. I saw the wheel when the builder
completed it. It had DT Alpine III spokes, Shimano XT hubs, and
Mavic D521 rims. It was built in 3 cross pattern. I stress
relieved it according to your method and with significant grip on
all opposing pairs of spokes. I checked the tension all around and
wrote it down on a piece of graph paper for future reference. The
wheel had very even tension and 120 kgf on all spokes.
That doesn't change what I said above. You must have a bum spoke
wrench.
Quoted message said:As an aside, the Park Tool site has a nice little Conversion
Calculator for their tension gauge and record keeping spreadsheet
at:
http://www.parktool.com/repair_help/TCC.shtml
Quoted message said:And then click on the link TCC 1.xls
Let's not get into the merits of spoke tension values. The subject is
spoke moving in the hub. If that were the case, my spokes and hubs
with around 300,000 miles on them should have worn out and release the
spokes by now.
Quoted message said:The wheel was from a local downhill rider.
I don't understand what "downhill racer" has to do with spoke
movement. Can you explain?
Quoted message said:He rode it for the a few weeks on some local downhill courses. The
rider brought the wheel over for me to look at because he suspected
that it was losing tension as the tone of the spokes was going down
in frequency. I noticed that that although the wheel was still
quite true, the spoke tension was down to 70 kgf tension on all
spokes. The nipples wouldn't turn. I then pulled off the rim tape
and saw remnants of the red Loctite on the inside threads of the
nipples. My point is that there was decreased tension in the spokes
and that it couldn't have come from the nipples unthreading from the
spokes.
Well you certainly build a good scenario. The trouble is that it does
not fit with the wheels I have built and observed, nor does you spoke
loosening make sense. For a spoke to loosen from spoke head setting
in the flange, the spoke would need to project from the flange as is
sink in and re-bend itself. You must realize that the elbow will not
do this but will rather break off from fatigue than reshape in use.
Quoted message said:Quoted message said:To me this little descriptions sound curiouser by the moment. A
deja-vue of olden days when such stories of wheels abounded. Are
you sure you didn't take Gerd Schraner's the art of wheel building
to literally?
Quoted message said:I haven't read Gerd's book.
Quoted message said:If the spokes don't move after tensioning them, what is the point of
improving the spoke line at the hub?
To prevent fatigue failures from a spoke loaded in bending. Spoke
material should ideally be only in tension from the head to the
thread. Improving the spoke line gets rid of significant bending
loads, but since you read that, you new that already.
Quoted message said:Could you explain your statement in the section "improving the Spoke
Line":
Quoted message said:"If there is an unsupported bend in a spoke, it will flex with
changing loads causing fatigue and early failure."
This is elastic strain in the spoke and not in the flange. It is
outside of the flange and lies just beyond the elbow. It's main
detrimental effect is adding bending stress to spoke tension. The
powerful effect of bending should be apparent from manually kinking a
spoke (bringing it beyond yield) compared to trying to stretch it to
yield manually. This is impossible. This should make clear what an
enormous force a slight bend can cause.
Quoted message said:Quoted message said:Is this flex just elastic, with no plastic deformation?
Quoted message said:Could you also explain how many repeats of stress relieving you
think it takes to "determine experimentally" the tension limit?
You have a tensiometer I take it, so you don't need to do that. The
method was mainly used for wheels before anyone used tensiometers or
had any idea that wheels should be tight for high performance.
Quoted message said:And if you know if there is any movement in the spoke elbow area
and/or distortion in the hub flange spoke holes during these
repeated tensioning cycles.
Flange deformation is an asymptotic effect that initially distorts
flange hole as spokes are tensioned. By the time the spokes are to be
stress relieved, nearly all the plastic deformation that will occur
has occurred. You can test this by measuring tension before and after
stress relieving. From the way you word your question, you seem to
believe that flanges continues to sag with every stress change. They
don't.
Fix your editor or maybe it's your typing!
Jobst Brandt
[email hidden]
