which spoke (2.0 or 1.8)

"commander_taco" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Planning to build a wheelset for a fixie. 32 hole van
dessel hub and alex rim. I am going with 3x lacing. Is
1.8mm (15 guage) adequate for the job?

or

Quoted message said:

should I stick with 2.0mm (14 guage). I don't like the
butted spokes so much, since they are expensive and the
strenght of a spoke under tension

is

Quoted message said:

determined by it smallest cross section anyway. The wheels
is going on a commute bike. I am 150lb rider. Openions?

1.8mm is adequate. I'd reconsider your opinion on "double-
butted" spokes though. They are more money, but they build
a good wheel. But there's nothing wrong with 1.8mm
straight in this application either.

Cheers,

Scott..

"commander_taco" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Planning to build a wheelset for a fixie. 32 hole van
dessel hub and alex rim. I am going with 3x lacing. Is
1.8mm (15 guage) adequate for the job? or should I stick
with 2.0mm (14 guage). I don't like the butted spokes so
much, since they are expensive and the strenght of a spoke
under tension is determined by it smallest cross section
anyway. The wheels is going on a commute bike. I am 150lb
rider. Openions?

You're light enough, so that means that almost anything will
work for you. One thing about a fixer though is that
"posting" to take up road shocks is more difficult, so that
rear wheels take a bit more abuse. I think double butted
spokes are worth the little extra expense in this
application, at least for the rear wheel.

jobs-<< I don't like the butted spokes so much, since they
are expensive and the strenght of a spoke under tension is
determined by it smallest cross section anyway. The wheels
is going on a commute bike. I am 150lb rider. Openions?

Quoted message said:

Quoted message said:

<BR><BR>

Use 14/15. Only a wee bit more $ for 32 of them and they
make a more durable wheel than any straight gauge spoke.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St.
Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali
costruite eccezionalmente bene"

commander_taco said:

Planning to build a wheelset for a fixie. 32 hole van
dessel hub and alex rim. I am going with 3x lacing. Is
1.8mm (15 guage) adequate for the job? or should I stick
with 2.0mm (14 guage).

15 gauge should be fine for you.

Quoted message said:

I don't like the butted spokes so much, since they are
expensive and the strenght of a spoke under tension is
determined by it smallest cross section anyway.

Not true! The spoke will rarely fail at the thin center
section. It will fail at the spoke elbow or nipple. Double
butted spokes give you strength where you need it and more
elasticity in the center section.

Art Harris

Qui si parla Campagnolo said:

jobs-<< I don't like the butted spokes so much, since they
are expensive and the strenght of a spoke under tension is
determined by it smallest cross section anyway. The wheels
is going on a commute bike. I am 150lb rider. Openions?

Quoted message said:

Quoted message said:

<BR><BR>

Use 14/15. Only a wee bit more $ for 32 of them and they
make a more durable wheel than any straight gauge spoke.

True. And in the case of DT (and possibly others), the
butted spokes are made with a higher quality steel; they
will not be less durable than straight gauge. /Robert

Harris said:

Not true! The spoke will rarely fail at the thin center
section. It will fail at the spoke elbow or nipple. Double
butted spokes give you strength where you need it and more
elasticity in the center section.

And at 150lb you'll want the bike to be as light as
possible, and these spokes save a worthwhile bit of weight
for the additional cost [1]. Heavy rider, light bike can be
fun. Light rider, heavy bike isn't!

[1] in the early 1990s we used to judge every "upgrade" by
dividing the weight saving in grams by the cost in
pounds. I'm not that sad now, but FWIW Kevlar-beaded
tyres, Flite saddles and Control Tech AK skewers came
out pretty well.

Robert Brown said:

Quoted message said:

Use 14/15. Only a wee bit more $ for 32 of them and they
make a more durable wheel than any straight gauge spoke.

Quoted message said:

True. And in the case of DT (and possibly others), the
butted spokes are made with a higher quality steel; they
will not be less durable than straight gauge.

Straight gauge and butted or swaged 1.8 or 2.0mm spokes come
of the same reel of wire. The mid section of the spokes is
swaged to a thinner diameter. Wire from which they are
formed, although having a high tensile strength, is ductile
enough to cold form spokes even though it is as work
hardened as it can get. Further forming does not alter its
ductility significantly.

Jobst Brandt [email hidden]

Quoted message said:

Robert Brown said:

Quoted message said:

Use 14/15. Only a wee bit more $ for 32 of them and they
make a more durable wheel than any straight gauge spoke.

Quoted message said:

True. And in the case of DT (and possibly others), the
butted spokes are made with a higher quality steel; they
will not be less durable than straight gauge.

Straight gauge and butted or swaged 1.8 or 2.0mm spokes
come of the same reel of wire.

yes they do.

Quoted message said:

The mid section of the spokes is swaged to a thinner
diameter. Wire from which they are formed, although
having a high tensile strength, is ductile enough to
cold form spokes even though it is as work hardened as
it can get.

no, it's not as work hardened as it can get.

Quoted message said:

Further forming does not alter its ductility
significantly.

yes it does. ductility drops and the material work hardens
as the butting process proceeds.

check the different strengths for d.t. spokes:

revo's
dtswiss.comDAT EN 30430224269.pdfOpen ↗
"center section up to 1300N/mm^2"

comp's
dtswiss.comDAT EN 30430224207.pdfOpen ↗
"center section up to 1200N/mm^2"

champ's
dtswiss.comDAT EN 30430224345.pdfOpen ↗
tensile strength 1000-1100N/mm^2 - the same spec as the non-
butted sections of both spokes above.

the more worked the material is in reducing it's cross
section, the more the tensile strength is increased as it it
progressively work hardened from 2.0 > 1.8 > 1.5mm

with respect, this is what the "real life" stress/strain
graphs in the back of your book show too.

Quoted message said:

Jobst Brandt [email hidden]

Quoted post said:

Originally posted by Jim Beam

B said:

Robert Brown said:

Quoted message said:

Use 14/15. Only a wee bit more $ for 32 of them and they
make a more durable wheel than any straight gauge spoke.

Quoted message said:

True. And in the case of DT (and possibly others), the
butted spokes are made with a higher quality steel; they
will not be less durable than straight gauge.

Straight gauge and butted or swaged 1.8 or 2.0mm spokes
come of the same reel of wire.

yes they do.

Quoted message said:

The mid section of the spokes is swaged to a thinner
diameter. Wire from which they are formed, although
having a high tensile strength, is ductile enough to
cold form spokes even though it is as work hardened as
it can get.

no, it's not as work hardened as it can get.

Quoted message said:

Further forming does not alter its ductility
significantly.

yes it does. ductility drops and the material work hardens
as the butting process proceeds.

check the different strengths for d.t. spokes:

revo's
dtswiss.comDAT EN 30430224269.pdfOpen ↗
"center section up to 1300N/mm^2"

comp's
dtswiss.comDAT EN 30430224207.pdfOpen ↗
"center section up to 1200N/mm^2"

champ's
dtswiss.comDAT EN 30430224345.pdfOpen ↗
tensile strength 1000-1100N/mm^2 - the same spec as the non-
butted sections of both spokes above.

the more worked the material is in reducing it's cross
section, the more the tensile strength is increased as it it
progressively work hardened from 2.0 > 1.8 > 1.5mm

with respect, this is what the "real life" stress/strain
graphs in the back of your book show too.

Quoted message said:

Jobst Brandt [email hidden] [/B]

Dear Jim and Jobst,

If I follow Jim's comment, the DT pdf files show that
swaging work hardens the DT spokes, raising their
tensile strength from 1000-1100nm/mm2 to 1200
and then 1300 as the mid-section shrinks from
2.0mm to 1.5mm.

But when I look at the "Spoke Strength" stress-strain
graphs in Figure 69 of "The Bicycle Wheel, Second Edition,"
I'm not sure what's going on.

In every case, the unbutted spokes reach a higher Kg
value than their unbutted versions, about 5-10% more.

But if the work-hardening effect is per mm2, as the
DT figures put it, then the butted versions might be
absolutely stronger because they're thicker.

In any case, I'm positive now that I don't understand
the graphs and hope to have them explained.

And now I see a comment that "In contrast to tests
performed for the first edition of this book, these
spokes withstood substantial elongation before
failure. . . ."

So I'm not even sure which edition and which
graphs we're talking about.

In short, what do the spoke test graphs show
about work hardening, strength, and so forth?
If Jobst is willing, I'd be glad to scan my second
edition pages 132-133 and put them up, or put
up graphs from other editions, so that people
can see what's being discussed.

Carl Fogel

Carl Fogel said:

And now I see a comment that "In contrast to tests
performed for the first edition of this book, these spokes
withstood substantial elongation before failure..."

Quoted message said:

So I'm not even sure which edition and which graphs we're
talking about.

If you read it then you were reading the current edition
that refers to an earlier edition that had more typical
stress strain curves.

Quoted message said:

In short, what do the spoke test graphs show about work
hardening, strength, and so forth? If Jobst is willing,
I'd be glad to scan my second edition pages 132-133 and
put them up, or put up graphs from other editions, so that
people can see what's being discussed.

I hope words will be adequate. The curves show that the
spoke, when reaching yield stress, continued to elongate at
constant tension (horizontal line) and because elongation
causes reduction in cross section, it implies that the wire
is getting stronger as its cross section reduces. However,
with a 300mm long (spoke), the change in cross section
caused by the small but otherwise significant strain shown
is essentially zero. Therefore, there is no strain hardening
occurring.

A person familiar with tensile tests should immediately
recognize the unusual flat characteristic of this tensile
test in contrast to the typical arch of most such tests.
Sample length also has significance. What's more, the spoke
did not fail in the extent of the test. I just kept getting
longer. Several were tested with the same result to
determine repeatability.

Jobst Brandt [email hidden]

Newsgroups: rec.bicycles.tech

Carl Fogel said:

And now I see a comment that "In contrast to tests
performed for the first edition of this book, these spokes
withstood substantial elongation before failure..."

Quoted message said:

So I'm not even sure which edition and which graphs we're
talking about.

If you read it then you were reading the current edition
that refers to an earlier edition that had more typical
stress strain curves.

Quoted message said:

In short, what do the spoke test graphs show about work
hardening, strength, and so forth? If Jobst is willing,
I'd be glad to scan my second edition pages 132-133 and
put them up, or put up graphs from other editions, so that
people can see what's being discussed.

I hope words will be adequate. The curves show that the
spoke, when reaching yield stress, continued to elongate at
constant tension (horizontal line) and because elongation
causes reduction in cross section, it implies that the wire
is getting stronger as its cross section reduces. However,
with a 300mm long (spoke), the change in cross section
caused by the small but otherwise significant strain shown
is essentially zero. Therefore, there is no strain hardening
occurring.

A person familiar with tensile tests should immediately
recognize the unusual flat characteristic of this tensile
test in contrast to the typical arch of most such tests.
Sample length also has significance. What's more, the spoke
did not fail in the extent of the test, it just kept getting
longer. Several were tested with the same result to
determine repeatability.

Jobst Brandt [email hidden]