spoke length?

A Muzi wrote:

You implied, I think, that these spokes were cut just for you. Although
I ¢¾ my Phil Wood spoke machine, if we had to cut a set of spokes for
more than one wheel out of fifty, we'd have to raise our spoke price.
It's terribly time consuming and hence economically inefficient. More
likely, someone counted your spokes from cases of pre-cut 301 and 303.

Most of the spokes I use are unusual in length, so I have to mail
order many of them. I use Danscomp.com since I discovered that
despite being a BMX-only supplier, they use full-length Sapim blanks
and cut all spokes to order. Even so, theirs are about the least
expensive top-quality spokes I've found.

I'm guessing that they use something besides a Phil spoke cutter,
because I've never gotten a sticky thread or ringed (rather than
threaded) spoke from them out of the hundreds I have ordered.

Chalo

J Taylor wrote:

Carl Fogel wrote:

An example of a truly excessive calculator that lets you put in the
desired tension, modulus of elasticity, thickness, and so on:

http://www.machinehead-software.co.u..._length_calcul...

Results are in tenths of a millimeter. It really ought to include a
field for temperature, since the spokes must shrink a little in cold
weather.

A very little. Values for steel are (from memory) about 8 millionths of an
inch per inch per degree; so a 100 degree change in an 11 inch spoke would
be on the order of a hundredth of an inch.

That's not particularly relevant unless the rim is made of Invar. In
cold temperatures, an aluminum rim contracts even more than the spoke,
making the spoke effectively _longer_ for our purposes even as it
becomes measurably shorter.

Chalo

On Jan 31, 1:04*pm, Chalo wrote:
J Taylor wrote:

Carl Fogel wrote:

An example of a truly excessive calculator that lets you put in the
desired tension, modulus of elasticity, thickness, and so on:

http://www.machinehead-software.co.u..._length_calcul....

Results are in tenths of a millimeter. It really ought to include a
field for temperature, since the spokes must shrink a little in cold
weather.

A very little. *Values for steel are (from memory) about 8 millionths of an
inch per inch per degree; so a 100 degree change in an 11 inch spoke would
be on the order of a hundredth of an inch.

That's not particularly relevant unless the rim is made of Invar. *In
cold temperatures, an aluminum rim contracts even more than the spoke,
making the spoke effectively _longer_ for our purposes even as it
becomes measurably shorter.

My spokes become loose in the cold? There has to be a marketing
opportunity in there somewhere. Rim warmers, maybe. -- Jay Beattie.

On 2008-01-31, Jay Beattie wrote:
On Jan 31, 1:04*pm, Chalo wrote:
[...]
That's not particularly relevant unless the rim is made of Invar. *In
cold temperatures, an aluminum rim contracts even more than the spoke,
making the spoke effectively _longer_ for our purposes even as it
becomes measurably shorter.

My spokes become loose in the cold? There has to be a marketing
opportunity in there somewhere. Rim warmers, maybe. -- Jay Beattie.

Perhaps pads made of a rubber-like material could be positioned to rub
against the rim while riding thus generating heat. The pads could be
operated by levers mounted on the handlebars.

On Jan 31, 2:36*pm, Ben C wrote:
On 2008-01-31, Jay Beattie wrote:

On Jan 31, 1:04*pm, Chalo wrote:
[...]
That's not particularly relevant unless the rim is made of Invar. *In
cold temperatures, an aluminum rim contracts even more than the spoke,
making the spoke effectively _longer_ for our purposes even as it
becomes measurably shorter.

My spokes become loose in the cold? *There has to be a marketing
opportunity in there somewhere. Rim warmers, maybe. -- Jay Beattie.

Perhaps pads made of a rubber-like material could be positioned to rub
against the rim while riding thus generating heat. The pads could be
operated by levers mounted on the handlebars.

That's awesome! Put them right behind the brake calipers. Quick, get
Carl to do a patent search! -- Jay Beattie.

Ahhhhhh INVAR is from Never-Never land.

Spokes measurement? Never ran the machine. There's a metal Nashbar
ruler taped to the kitchen counter formica. Carelessness in measuring
throws lengths off 1-1.5mm. Used and prevuiously tightened down to
running torques but new spokes and unused new spokes measure
differently: 1mm plus.

"Spokes do not stretch in any practical or measurable sense." Try it.
Remove a new spoke in a newly built wheel and measure against a new
unused spoke. While your measures may not differ, take note the bends
are different and the measures can be different, especially over at
the MO. The spoke doesn't stretch but the bend radii or measuring
point produces a longer measurement. Yes, 16mm nipples not 6mm. That;s
a good point to remember, spokes in stock. Like the lengths I needed
were not in stock so....

The one poster sez stretch is around or up to .75mm.

Then I left the spokes slack. Like Dirksen said, "a mm here and a mm
there and pretty soon you're screwed with the wrong spokes again."
I guess I'll try 1mm short of the rim.

When I first started whining, the MO said "no those are the right
spoke lengths, we rarely make mistakes, you can talk to our expert
wheelbuilder." And I said "&&^^TT$%#22" and ")(((&R$4442RRR" But the
MO trapped me as the spokes are for:
FOUR CROSS 36 HOLE and 530 Deore/Sun Rhino's (at least I received 36
hole rims and 36 hole hubs this time and guess who did that? You'd
swear they send their work out to the Zoo or Rhode Island)

So the MO sez, "WE ALWAYS BUILD OUR TREKKING WHEELS FOUR CROSS."

The ISO standard measure? Could the Iso standard entered into software
turn double wall specs into single wall measurements?
Or maybe the MO assumes the double wall is the same as a single wall.
That may be but as mentioned previously, software over at the Trek LBS
turns double wall specs into single wall lengths.

NOW, "The ERD is the diameter to which the threaded ends of spokes are
to
reach, and that is the top of spoke nipples inserted in the rim.
This
can be assessed by measuring the outside rim diameter and subtracting
twice the distance measured down to the spoke nipple head from this
outer diameter... meaning Effective Rim Diameter for spoking."

WHY?

Measure the diameter. Practice measuring the diameter. Write that
number down.
Take a spoke and stick it in the eyelet until flush with the outside
eyelet. Magic Tape the shaft where the shaft enters the inside eyelet
surface. Measure that and add to rim diameter.

BUT THAT'S NO GOOD! The real life spoke should be shorter than the
inside eyelet where the nipple seats.
Are spoke calcs taking this into account or am I asking spoke cals to
take my personal opinion into account where a spoke threading should
not bottom out in practical use when building wheels?

JB,


"subtracting
twice the distance measured down to the spoke nipple head"

how does does TWICE THE DISTANCE prove out? Is there an ISO standard
at work here?
Twice the distance could be somewhere in the vicinity of the length
I'm looking for minus slack spokes
BUT all rims are different are they not? Or is there a standard
operating there control rim design? No way on that right?
and lesser, what part of the spoke head-the inner seat on the outer
eyelet, right?

datakoll

On Thu, 31 Jan 2008 13:04:41 -0800 (PST), Chalo
wrote:

J Taylor wrote:

Carl Fogel wrote:

An example of a truly excessive calculator that lets you put in the
desired tension, modulus of elasticity, thickness, and so on:

http://www.machinehead-software.co.u..._length_calcul...

Results are in tenths of a millimeter. It really ought to include a
field for temperature, since the spokes must shrink a little in cold
weather.

A very little. Values for steel are (from memory) about 8 millionths of an
inch per inch per degree; so a 100 degree change in an 11 inch spoke would
be on the order of a hundredth of an inch.

That's not particularly relevant unless the rim is made of Invar. In
cold temperatures, an aluminum rim contracts even more than the spoke,
making the spoke effectively _longer_ for our purposes even as it
becomes measurably shorter.

Chalo

Dar Chalo,

Even worse, at least one calculator nibbles its fingernails and
worries about how much the spoke tension caused the aluminum rim to
contract.

The screen shot here reveals that the sample rim suffers 0.911 mm of
rim shrinkage:

http://www.machinehead-software.co.u...alculator.html

I don't know whether the software calculates how much the rim bulges
inward at the spoke hole, but it certainly ought to!

We have the tools to calculate spoke lengths to 0.1 mm, so it's a
mystery why spokes don't come in 0.5 mm lengths. After all, half a
millimeter is almost exactly one turn of a 52 tpi spoke nipple.

Cheers,

Carl Fogel

Fogel the English major back from running the front range.
Another ticket at 125 in a 15 zone.

Does the english spoke calc come with a Fogel endorsement or is it a
thumbs down?
or a matter of curiosity? Once downloaded, does it gum up the works?

After all 1/2 mm is amost extacly 1/2 nipple turn. A GREAT PIECE OF
INFORMATION!
What is this almost exactly? Joyce?

On Thu, 31 Jan 2008 17:29:44 -0800 (PST), datakoll
wrote:

Fogel the English major back from running the front range.
Another ticket at 125 in a 15 zone.

Does the english spoke calc come with a Fogel endorsement or is it a
thumbs down?
or a matter of curiosity? Once downloaded, does it gum up the works?

After all 1/2 mm is amost extacly 1/2 nipple turn. A GREAT PIECE OF
INFORMATION!
What is this almost exactly? Joyce?

Dear Gene,

Er, half right.

Divide 25.4 millimeters per inch by 52 threads per inch.

You should get almost exactly 0.5 mm per thread, or half a millimeter
for each full turn of the spoke nipple.

Cheers,

Carl Fogel