spoke length?
datakoll
2.0 Spokes for my MO Monodog 29er's wheels are MO too long, again.
The wheel is laced on a dishing beam, hub centered, nipples seated but
not tightened.
So I have the average measurements from edge of spoke hub hole to
inside rim at the rim eyelet.
Using 6mm nipples, the spokes should be cut to the measurement to the
eyelet, 1mm short of the eyelet or 2 mm short of the eyelet ?
What is common practice here for a measurement that will account for
spoke stretch, taking up spoke bend, and hub hole wear?
jim beam
> 2.0 Spokes for my MO Monodog 29er's wheels are MO too long, again.
>
> The wheel is laced on a dishing beam, hub centered, nipples seated but
> not tightened.
>
> So I have the average measurements from edge of spoke hub hole
eh? you need the hub dimensions, then the rim dimensions, the spoke
count, then the spoke crossing pattern. the hub spoke circle diameter
should be to the center of the spoke hole. calculate from there.
calculation options include doing the math yourself, letting damon
rinard do it for you, or letting someone like d.t. do it for you.
> to
> inside rim at the rim eyelet.
use the published manufacturer erd.
>
> Using 6mm nipples, the spokes should be cut to the measurement to the
> eyelet, 1mm short of the eyelet or 2 mm short of the eyelet ?
i prefer to the bottom of the spoke nipple screwdriver slot.
>
> What is common practice here for a measurement that will account for
> spoke stretch, taking up spoke bend, and hub hole wear?
for 2.0mm spokes, stretch is negligible. the rest comes out in the wash
when you use the rinard solution. but it's garbage in, garbage out.
you need to make sure your input data is precise and correct.
datakoll
no, real life setup on the dishing beam is more accurate and reliable.
The spokes are here, the wheel is real, why use math-or why use
incorrect inputs into the equation.
spoke math, in the current problem of too long mail order spokes,
seems to give a math answer. The math answer may be correct but itsa
not gonna build the wheel. The math Mall Oder spokes tighten down as
the nipples seat onto the eyelets outside dim-ension.
Great math and off to Puget Sound in the Spruce Goose.
Prior attempts at MalOder spokes were fumbled by clac software. For an
as yet unexplained reason, clac software insists on single wall rim
diameters when the operator is typing double wall rim dimenesion into
the computer?
you prefer what to the bottom of the spoke slot? the end of the spoke
when fully torqued down? Rinard is giving you that dimension? I don't
believe that ans it sounds like something JB would start a parade on.
Rocket Science spoke lengths. Sure, when you find a rocket scientist
is a bike warehouse cutting Maul Odor spokes or a rocket science spoke
measurement device. A 303mm in a batch of 36 will vary 1.5 either way.
Then what? And don't say filum down.
No way! no room for error, dents, bashes, or hole wear.
and I don't know where Shimano hid standard dimensions.
If you use the math, it's possible the math isn't giving you real life
dimensions, but how would you know that? Rinard et al doesn't let on
to it do they?
My standard from scratch method became buy 8 spokes from an eyeball/
tape measure with moderate experience and set up the wheel on dishing
beam after the odor came in backwards, again.
datakoll
Science and a full thread engagment? when the potential for running
out of room is at hand.
More JB, torque the rim until you break it then back of a little.
No point to it.
jim beam
> On Jan 30, 10:04�pm, jim beam <spamvor...@bad.example.net> wrote:
>> datakoll wrote:
>>> 2.0 Spokes for my MO Monodog 29er's wheels are MO too long, again.
>>> The wheel is laced on a dishing beam, hub centered, nipples seated but
>>> not tightened.
>>> So I have the average measurements from edge of spoke hub hole
>> eh? �you need the hub dimensions, then the rim dimensions, the spoke
>> count, then the spoke crossing pattern. �the hub spoke circle diameter
>> should be to the center of the spoke hole. �calculate from there.
>> calculation options include doing the math yourself, letting damon
>> rinard do it for you, or letting someone like d.t. do it for you.
>>
>>> to
>>> inside rim at the rim eyelet.
>> use the published manufacturer erd.
>>
>>
>>
>>> Using 6mm nipples, �the spokes should be cut to the measurement to the
>>> eyelet, 1mm short of the eyelet or 2 mm short of the eyelet ?
>> i prefer to the bottom of the spoke nipple screwdriver slot.
>>
>>
>>
>>> What is common practice here for a measurement that will account for
>>> spoke stretch, taking up spoke bend, and hub hole wear?
>> for 2.0mm spokes, stretch is negligible. �the rest comes out in the wash
>> when you use the rinard solution. �but it's garbage in, garbage out.
>> you need to make sure your input data is precise and correct.
>
> no, real life setup on the dishing beam is more accurate and reliable.
but you've just proven that not to be true!
> The spokes are here, the wheel is real, why use math-or why use
> incorrect inputs into the equation.
because it gives you the correct result first time, every time. there
is a reason the math exists. see above!
>
> spoke math, in the current problem of too long mail order spokes,
> seems to give a math answer. The math answer may be correct but itsa
> not gonna build the wheel. <snip>
then the math is not being used correctly. garbage in, garbage out.
Ben C
>
> 2.0 Spokes for my MO Monodog 29er's wheels are MO too long, again.
>
> The wheel is laced on a dishing beam, hub centered, nipples seated but
> not tightened.
>
> So I have the average measurements from edge of spoke hub hole to
> inside rim at the rim eyelet.
>
> Using 6mm nipples, the spokes should be cut to the measurement to the
> eyelet, 1mm short of the eyelet or 2 mm short of the eyelet ?
I think the math those of us who do the math do is based on making the
spoke exactly the ERD length.
The ERD is I think the distance to where the nipple sits in the rim.
So based on that you don't want 1mm short or 2mm short but 0mm short.
But a mm or two doesn't matter. I usually find the spokes come quite
far up the nipples such that you can't do final tightening with a
screwdriver from the top because the end of the spoke is in the way.
But the LBS I bought spokes from only stocked even numbers of mm, and
math predicted an odd number, so I got them officially 1mm too long to
start with.
Are nipples threaded all the way to the bottom anyway? You don't want
the spokes too short.
> What is common practice here for a measurement that will account for
> spoke stretch, taking up spoke bend, and hub hole wear?
Stretch and bend should be almost nothing. Hub hole wear, perhaps that
could mean 1mm less in an extreme case? No need to worry about it. 1mm
either way is no problem.
dabac
jim beam Wrote:
> ...then the math is not being used correctly. garbage in, garbage out.
I'll happily trust the math itself, but sometimes it can be a real PITA
to track down the real dimensions, particularly when there are
conficting numbers available. A hub is no big deal to measure, but a rim
is more awkward.
If you have the stuff at hand I suppose it's reasonably doable, but if
you want to place an order for both hub, rim and spokes simultaneously
it can be a real nuisance.
--
dabac
datakoll
what's proven is:
the theoreticians aren't building wheels
have poor memories
can't answer the question
jim beam
sure. but you can't use the datakoll method without having the stuff at
hand either!
[measuring rim erd is easy enough without special tools. use two
spokes, two spoke nipples, and a tape measure. measure the spoke nipple
dimensions to where you want, then thread them onto the spokes head
down, i.e. opposite to the way you normally do. then have an assistant
hold these two into opposite holes in the rim - so the spoke nipples are
situated normally like they would be in a laced wheel, only the spokes
aren't in the way - while you measure the distance between them. add to
that measurement, a double quantity of the spoke nipple measurement you
made earlier, and you have the number you need for calculation.]
jim beam
dude, you're by far the wittiest guy on this group. but you're also the
hardest to help when you don't want to listen.
in this case, there is a real, simple, technical solution to the
question you originally asked. take the prescribed measurements, crank
the handle on the calculator, and the numbers you need drop out of the
bottom. and unless your measurements are wrong, the answers you get
from this method are guaranteed right.
jim beam
and if you post the input data, i'll post the output data.
datakoll
E.R.D.
Effective Rim Diameter. This is the rim diameter measured at the
nipple seats in the spoke holes. The E.R.D. is needed for calculating
the correct spoke length.
See also the Spocalc Spoke Length Calculator on this
site. -sheldon brown's bicycle dictionary
my experience, with other people's calculations sent MO, is a SPOKE
END running to the nipple's seat or I assume correct if not-the
outside eyelet, has the nipple run out threading to tighten further.
Wha happens, and I did this once, is the wheel is set to go annnnnnd
final torque levels are rrrrreachable, if reachable, only thru
twisting nipples past final designed threading.
There are drawings designed to eliminate this problem at the spoke
clac setup point. Apparently the drawings are unclear at the MO.
That's kinda what I'm asking: where is THAT point for the spoke end?
dabac writes, 'a pain if the parts aren't on hand.' That's why the MO
should run a competent spoke calc database. The 700c Sun Rhinos and
Deore hubs ordered here aren't 54 303mm and 18 301 mm, the parts not
Pre-war French Retro, the process not obscure.
What happens is the parts are on hand but the spokes are too long. The
spokes are in, the hub centered: so where do I measure to or deduct
froj to get a 'perfetc' length to UPS and recut?
In one MO shipment (names and profanity withheld because its Thursday)
the retard at the quaint little nayborhood shop sent single wall
spokes for a double wall 700 rim. REASON? I didn't have a 700 rim caws
the manufacturer didn't make the specified rim. Typical of the mental
challenged. Therefore, the 8 spoke-dishing beam method.
datakoll
to clarify the preceeding(?) if the spokes are tightened down now at
the dishing beam, the bends stretch over the hub hole, measuring
becomes difficult at the recutting machine. That's why a guesstimate
based on experience not math theorizing on what's happening in Parsec
2.
Jay Beattie
What is the 8 spoke-dishing beam method?
Throw your rim and hub dimensions in to a decent spoke length
calculator (there are many on the internet), and get the right length
and order some of those spokes. If you question one calculator, throw
the numbers in to three or four others and see what you come up with.
You have very common components, and the dimensions (ERD, flange
height, etc.) are also available on the internet in many places.
Unless you have a Phil spoke cutting/threading tool, trimming a
wheel's worth of spokes (or half a wheel) does not make sense -- at
least to me. With that said, I am sure that ten people will jump out
of the woodwork and say that they do it on a daily basis with great
success and without munging the threads. YMMV. I have built wheels
with spokes that were slightly too long because I have 30 years of
spokes around the house and sometimes just use what I have. If the
spokes project out of the nipple by a mm or so after final tension, I
grind them off with a Dremel tool or a file -- unless it is a rim with
a socket, and the spoke ends are below the socket, then I do nothing.
If you have more projection than that, then the nipples are bottoming
out on the threads; the wheel is not getting up to maximum tension,
and it is time to start over with the right length spokes. Another
problem with two long spokes is that, even if trimmed, they may bottom
out later if you have to tighten the wheel to account for a dent or
other insult to the rim. You should just get the right length spoke
to start with. -- Jay Beattie.
jobst....@stanfordalumni.org
>> 2.0 Spokes for my MO Monodog 29er's wheels are MO too long, again.
>> The wheel is laced on a dishing beam, hub centered, nipples seated but
>> not tightened.
>> So I have the average measurements from edge of spoke hub hole to
>> inside rim at the rim eyelet.
>> Using 6mm nipples, the spokes should be cut to the measurement to
>> the eyelet, 1mm short of the eyelet or 2 mm short of the eyelet?
> I think the math those of us who do the math do is based on making
> the spoke exactly the ERD length.
> The ERD is I think the distance to where the nipple sits in the rim.
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.
> So based on that you don't want 1mm short or 2mm short but 0mm short.
> But a mm or two doesn't matter. I usually find the spokes come quite
> far up the nipples such that you can't do final tightening with a
> screwdriver from the top because the end of the spoke is in the way.
I haven't found a method of using a screw driver for final tightening,
or truing for that matter. A spoke nipple driver is handy to get
started with all spoke equally engaged.
> But the LBS I bought spokes from only stocked even numbers of mm,
> and math predicted an odd number, so I got them officially 1mm too
> long to start with.
> Are nipples threaded all the way to the bottom anyway? You don't
> want the spokes too short.
The small end of spoke nipples usually have about 3mm smooth bore
before threads begin.
>> What is common practice here for a measurement that will account
>> for spoke stretch, taking up spoke bend, and hub hole wear?
> Stretch and bend should be almost nothing. Hub hole wear, perhaps
> that could mean 1mm less in an extreme case? No need to worry about
> it. 1mm either way is no problem.
Amen.
Jobst Brandt
A Muzi
I assume you either used a spoke chart or software? Someone either
misread the chart or used an erroneous input with software.
However, it isn't all that terrible. Now that you have a built or mostly
built wheel, it should be straightforward to interpolate and correct. If
your 292 are 6mm too long, ask for 276, etc. Shoot for the inside edge
of the rim or to the nipple slot ( a difference of ~1mm)
What are '6mm nipples'? Short are usually 12mm, the older long ones were
mostly 16mm (wood rims 20mm) but the threaded portion varies little if
at all:
http://www.yellowjersey.org/photosfromthepast/NIPPLES.JPG
Spokes do not stretch in any practical or measurable sense.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
carl...@comcast.net
wrote:
>Spokes do not stretch in any practical or measurable sense.
Dear Andrew,
Spoke stretch is negligible, but many calculators actually include
it--just google for "spoke stretch" and calculator:
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.uk/bike/spokes/spoke_length_calculator.html
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.
***
Near the bottom of this calculator's page, the author mentions using
Jobst's calculation for spoke stretch:
http://www.appliedthought.com/danny/Spoke/SpokeCalculator.html
***
Jobst's calculation for "Spoke Elongation" was corrected down from
1.24 mm in the first and second edition (an oops involving 180 kg
tension) to this smaller 1000 newton figure in the 3rd edition:
3. SPOKE ELONGATION FROM TENSIONING
dL= P / K Elongation
K = 1.34e6 N/mm Spoke elasticity (from Eq. 2)
P = 1000N Tension in spoke
dL= 1000/1.34e6 = 746e-6 m = 0.75 mm
***
Again, I agree that ~0.75 mm of spoke stretch is not worth worrying
about, particularly when many calculators include it anyway.
Cheers,
Carl Fogel
A Muzi
Without knowing which Deore rear hub you have, a Deore front 36h 3x on
Rhino is 292mm, not 303mm. You're right, they were not even close.
_
> On Thu, 31 Jan 2008 13:17:53 -0600, A Muzi <a...@yellowjersey.org>
> wrote:
>
>>Spokes do not stretch in any practical or measurable sense.
>
> Dear Andrew,
>
> Spoke stretch is negligible, but many calculators actually include
> it--just google for "spoke stretch" and calculator:
>
> http://www.google.com/search?as_q=%22spoke+stretch%22+calculator&hl=en&num=10&btnG=Google+Search&as_epq=&as_oq=&as_eq=&lr=&cr=&as_ft=i&as_filetype=&as_qdr=all&as_nlo=&as_nhi=&as_occt=any&as_dt=i&as_sitesearch=&as_rights=&safe=images
>
> 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.uk/bike/spokes/spoke_length_calculator.html
>
> 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.
A Muzi
>>> what's proven is:
>>> the theoreticians aren't building wheels
>>> have poor memories
>>> can't answer the question
datakoll wrote:
> to clarify the preceeding(?) if the spokes are tightened down now at
> the dishing beam, the bends stretch over the hub hole, measuring
> becomes difficult at the recutting machine. That's why a guesstimate
> based on experience not math theorizing on what's happening in Parsec
> 2.
Length is normally taken from the inside of the curve to the end.
Machines which hold the spoke on the outside of the curve correct for
that. Brands do vary but only in the under 0.5mm range.
You implied, I think, that these spokes were cut just for you. Although
I ♥ 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.
Chalo
>
> You implied, I think, that these spokes were cut just for you. Although
> I ♥ 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
Chalo
>
> 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:
>
>
> > 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
Jay Beattie
My spokes become loose in the cold? There has to be a marketing
opportunity in there somewhere. Rim warmers, maybe. -- Jay Beattie.
Ben C
> On Jan 31, 1:04 pm, Chalo <chalo.col...@gmail.com> 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.
Jay Beattie
That's awesome! Put them right behind the brake calipers. Quick, get
Carl to do a patent search! -- Jay Beattie.
datakoll
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?
datakoll
"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
carl...@comcast.net
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.uk/bike/spokes/spoke_length_calculator.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
datakoll
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?
carl...@comcast.net
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
Tom Sherman
> datakoll wrote:
>> what's proven is:
>> the theoreticians aren't building wheels
>> have poor memories
>> can't answer the question
>>
>
>
"jim beam" is correct.
--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth
Tom Sherman
> ...
> 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.
>
oven at low heat before mounting.
Tom Sherman
inside his rims.
A Muzi
Spokes are 56 tpi. 1/2 turn advances 1/112 inch or 0.226mm
A Muzi
>>> what's proven is:
>>> the theoreticians aren't building wheels
>>> have poor memories
>>> can't answer the question
> "jim beam" wrote:
>> dude, you're by far the wittiest guy on this group....
Tom Sherman wrote:
> "jim beam" is correct.
Me three. Gene's contributions are greatly appreciated.
jb, Tom and I are at one in this(!).
carl...@comcast.net
wrote:
>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?
>
>Spokes are 56 tpi. 1/2 turn advances 1/112 inch or 0.226mm
Dear Andrew,
Aaargh! That'll teach me to trust my memory!
Luckily, despite my carelesness, it's still almost exactly half a
millimeter per turn of the spoke nipple.
Wrong 52 tpi, my mistake:
(25.4 mm / inch) / (52 threads / inch ) = 0.488 mm / thread
Right 56 tpi, Andrew knows threads per inch:
(25.4 mm / inch) / (56 threads / inch) = 0.4537 mm / thread
Cheers,
Carl Fogel
datakoll
OK OK
you know if you gather 5 names and ten readers someone will put a tire
in an oven no problem. The nipple turn is useable conceptual
information added to Sheldon Brown's Wheel Building. Thinking of the
wheel in millimeters as you go: in neon red off course.
Carl, is that spoke calc from Machinist Head foolproof software?
The Spoke Pattern Explorer For Wheel Building may answer spoke
questions from the 8 spoke and dishing beam guesstimate approach.
What does the 530 Deore/SiunRhino 2.0 36 4 cross work to on Madison
software?
BTW, was a beautiful spring day fading into a beatiful fall afternoon,
falling leaves. Into Wal and back with 100 pounds and a uh Pilates for
dry eskimo rolling. Naybors beginning to see the deal: called out "now
he's getting 40 mpg from that truck."
jim beam
> OK OK
>
> you know if you gather 5 names and ten readers someone will put a tire
> in an oven no problem. The nipple turn is useable conceptual
> information added to Sheldon Brown's Wheel Building. Thinking of the
> wheel in millimeters as you go: in neon red off course.
>
> Carl, is that spoke calc from Machinist Head foolproof software?
yes, damon's numbers are correct - i checked. and it's just a
spreadsheet. if you don't have excel, "open office" opened it and ran
it ok last time i looked.
jim beam
> 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?
no. rim beds are not part of the iso measurements, hence individual
erd's for individual rims.
> 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?
>
dude, just look up the dimensions and calculate! or measure the bits
cited and calculate! if you don't, you're in the expensive and time
consuming world of pointless iteration. it's not like people won't do
this stuff for you if you post the right data.
Ryan Cousineau
A Muzi <a...@yellowjersey.org> wrote:
> >> datakoll wrote:
> >>> what's proven is:
> >>> the theoreticians aren't building wheels
> >>> have poor memories
> >>> can't answer the question
>
> > "jim beam" wrote:
> >> dude, you're by far the wittiest guy on this group....
>
> Tom Sherman wrote:
> > "jim beam" is correct.
>
> Me three. Gene's contributions are greatly appreciated.
> jb, Tom and I are at one in this(!).
That can't be right.
--
Ryan Cousineau rcou...@gmail.com http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."
Chalo
>
> Chalo wrote:
> >
> >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.
>
> worries about how much the spoke tension caused the aluminum rim to
> contract.
I should have expected that. Now we're going to have to come up with
an almost infinitely stiff rim material to address such sophisticated
concerns. We can add another potential use for synthetic diamond to
the already lengthy wish list!
> 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.
Not that it matters, but I believe they are 56 tpi threads. At least
a #2-56 nut will thread onto a 2.0mm spoke with obvious disparity only
in its diameter.
Chalo
jim beam
> In article <13q50q4...@corp.supernews.com>,
> A Muzi <a...@yellowjersey.org> wrote:
>
>>>> datakoll wrote:
>>>>> what's proven is:
>>>>> the theoreticians aren't building wheels
>>>>> have poor memories
>>>>> can't answer the question
>>> "jim beam" wrote:
>>>> dude, you're by far the wittiest guy on this group....
>> Tom Sherman wrote:
>>> "jim beam" is correct.
>> Me three. Gene's contributions are greatly appreciated.
>> jb, Tom and I are at one in this(!).
>
> That can't be right.
>
jim beam
and thus mavic's aluminum spoke usage is vindicated...
carl...@comcast.net
Dear Chalo,
It's nice of you to correct me so gently, but . . .
I was just flat wrong, and you and Andrew (and probably others)
noticed it right away--56 tpi, not 52 tpi.
As for the calculators, some even try to factor in the extra length
involved in the tiny bends of 3-cross versus radial lacing.
Cheers,
Carl Fogel
Michael Press
dabac <dabac....@no-mx.forums.cyclingforums.com> wrote:
> jim beam Wrote:
> > ...then the math is not being used correctly. garbage in, garbage out.
>
> I'll happily trust the math itself, but sometimes it can be a real PITA
> to track down the real dimensions, particularly when there are
> conficting numbers available. A hub is no big deal to measure, but a rim
> is more awkward.
> If you have the stuff at hand I suppose it's reasonably doable, but if
> you want to place an order for both hub, rim and spokes simultaneously
> it can be a real nuisance.
Don't Panic.
Good instructions for accurately measuring effective rim diameter.
<http://www.sheldonbrown.com/rinard/spocalc.htm>
Best to measure at least 3 different diameters; for practice,
to detect a mis-measurement, to detect a rim out of round.
--
Michael Press
Ben C
[...]
> 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?
That's the definition of ERD.
> 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?
Calculators should give you a length based on the ERD. In other words,
they assume you want the spoke to reach the top of the nipples.
If you want them a bit shorter (matter of personal opinion) then
subtract 1mm from the ERD before you put it into the calculator.
I wanted to be sure how spoke calculators worked and whether they
contained personal opinions of their authors. I managed to replicate the
results of the DT one with just the formula on Wikipedia and subtracting
half the spoke hole diameter at the end. Since they ask for spoke hole
diameter it must be involved.
But I can tell you for sure it is working on the assumption that you
want spoke to reach exactly the point the ERD is measured from.
You can check my program if you like. It isn't any better than the
Rinard spreadsheet or any other calculator, but it might be clear what
the maths is. All distances in the same unit (use mm).
datakoll
"Calculators should give you a length based on the ERD. In other
words,
they assume you want the spoke to reach the top of the nipples.
If you want them a bit shorter (matter of personal opinion) then
subtract 1mm from the ERD before you put it into the calculator. " -
BEN C.
Andrew Muzi also suggests the program his shop's using has an ERD just
touching the inside rim surface.
yes. I agree. I am confused? maybe.
My problem is with double wall rims: Sun Rim's Cr-18 and Sun Rim's
Rhino. Mail Odor and LBS software did not come up with the correct
lenghts.
The LBS was selling spokes so foolery is not on there.
When I used the LBS computer, recently deceased, 1 out of 6 tries
coughed up the correct lengths. The owner didn't extract any right
lengths. Computer dummy hasn't learned to write paths and goes on a
menatl trial and error list so we don't know how.
But what kept happening was spoke ends were too long, in the best
length's threaded down just as the nipple seated loosely into eyelet.
From the software directions, maybe misread, it appeared to me that
was the ERD, where the spoke threaded fully and at that same cosmic
instant reached full Jobst Brandt Group One Wheel perfection seating
down immovabbley into the eyelet. Ahhhhhh...
But that's wrong. The ERD is from axle center to inside rim surface?
AS SHELDON BROWN'S GLOSSARY:
E.R.D.
Effective Rim Diameter. This is the rim diameter measured at the
nipple seats in the spoke holes. The E.R.D. is needed for calculating
the correct spoke length.
That said. Jim Beam wants to know why not measure. Well, because the
Mail Odor Wharehouse(s) say
NO PROBLEM! WE HAVE A SPOKE CALCULATOR.
then I have the parts and do a pre-build lacing on the tubahfour (red
oak). The question was: WHERE DOES THE EXPERIENCED WHEELBUILDER END
HIS SPOKES? touching the rim, 1mm from the rim ...
and the answers are:
touching the rim
1mm from the rim
or maybe 2mm from the rim if the spokes in the pretrial are
untightened
BUT keep in mind other forces may lenghten the spoke 1-2mm so
excercise caution.
and you can read, spoke calcs aren't producing for me.
I don't need to do this again unless 650B goes into monopoly.
eyyyahhhhh.
wouldn't it be cool. ahh the spokes the hub the rim. let's see string
this together. true it up. ahhh nice wheel.
forgetaboutit. ^%#!!QWAS9)*!!xx
jobst....@stanfordalumni.org
> "Calculators should give you a length based on the ERD. In other
> words, they assume you want the spoke to reach the top of the
> nipples.
> If you want them a bit shorter (matter of personal opinion) then
> subtract 1mm from the ERD before you put it into the calculator. "
> Andrew Muzi also suggests the program his shop's using has an ERD
> just touching the inside rim surface.
> yes. I agree. I am confused? maybe. My problem is with double
> wall rims: Sun Rim's Cr-18 and Sun Rim's Rhino. Mail Odor and LBS
> software did not come up with the correct lengths.
> The LBS was selling spokes so foolery is not on there. When I used
> the LBS computer, recently deceased, 1 out of 6 tries coughed up the
> correct lengths. The owner didn't extract any right lengths.
> Computer dummy hasn't learned to write paths and goes on a mental
> trial and error list so we don't know how.
> But what kept happening was spoke ends were too long, in the best
> length's threaded down just as the nipple seated loosely into
> eyelet. From the software directions, maybe misread, it appeared to
> me that was the ERD, where the spoke threaded fully and at that same
> cosmic instant reached full Jobst Brandt Group One Wheel perfection
> seating down immovably into the eyelet. Ahhhhhh...
> But that's wrong. The ERD is from axle center to inside rim
> surface?
> AS SHELDON BROWN'S GLOSSARY:
> E.R.D.
> Effective Rim Diameter. This is the rim diameter measured at the
> nipple seats in the spoke holes. The E.R.D. is needed for
> calculating the correct spoke length.
That's one interpretation but since the term arose first in "the
Bicycle Wheel, as did the geometric equations that are commonly used
today, I think this is not correct because that diameter is used to
calculate the diagonals from sums of squares to give the length to the
outer end of spokes. That point being a nipple head farther out.
The proper length should reach the end of the nipple when tight, not
the bed of the rim, which is as much as 3mm short of that. That is
why it is called an "effective rim diameter", because it is not
theinner outer or other real diameters.
> That said. Jim Beam wants to know why not measure. Well, because the
> Mail Odor Warehouse(s) say " NO PROBLEM! WE HAVE A SPOKE CALCULATOR."
> then I have the parts and do a pre-build lacing on the tubahfour (red
> oak). The question was: WHERE DOES THE EXPERIENCED WHEELBUILDER END
> HIS SPOKES? touching the rim, 1mm from the rim ...
> and the answers are:
> touching the rim
> 1mm from the rim
> or maybe 2mm from the rim if the spokes in the pretrial are
> untightened
> BUT keep in mind other forces may lenghten the spoke 1-2mm so
> excercise caution.
> and you can read, spoke calcs aren't producing for me.
> I don't need to do this again unless 650B goes into monopoly.
> eyyyahhhhh.
> wouldn't it be cool. ahh the spokes the hub the rim. let's see
> string this together. true it up. ahhh nice wheel.
> forgetaboutit. ^%#!!QWAS9)*!!xx
Eh? So waht was the point other than spreading incorrect information.
Jobst Brandt
Tom Sherman
>
> Don't Panic....
>
And remember to bring your towel!
A Muzi
In other correspondence with Gene today, I snapped a photo of a wheel
our #1 wheelbuilder finished a couple hours ago. Although the nipple
brand we currently prefer can thread all the way through, not all brands
can. Some nipple threads bind terribly as the spoke extends into the
slot. We shoot for a length just at the inside edge of the rim or at the
start of the slot as shown here:
http://www.yellowjersey.org/photosfromthepast/SPOKDEPT.JPG
If you work with any given spoke calculation software regularly, you can
tweak your results as finely as you like, down to that 1mm difference
between bottom of slot and top of slot.
datakoll
Ok we can flag this down. Beam is right. Forget the calc's database
because the calc software is about to choose an ERD for you and right
off the results aren't headed your way.
The spoke calc is probbably Brandt's math child and that ERD is a
spoke end "fully" inserted into the nipple, all threads used, no
allowance for error or wear and so if your wheel building skills are
building that type wheel that's your ERD. Why, practically anyone
would build a wheel with an ERD that long? Is there a practical or
strength advantage for limiting building alternatives thru striving
toward math perfection?
The Group 2 or wheel building slob like me needs an ERD or final
result spoke end position ( FRSEP ) falling short of full thread
use. leaving room for error, anomalies in the earth's rotational
speed, gross stupidity, that kinda thing.
Does the discussion answer why MO's deliver the wrong lenghts? I guess
so. Its kinda like the LBS telling you that's how it works when you
know the LBS never rides a bike so how could the LBS know?
datakoll
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Calling the base of the nipples' screwdiver slots an "effective" final
spoke end position supports a non-functioning reality.
Am I distorting what is meant by the final spoke end position?
Chalo
Pressed to choose, I think I'd be better off with stainless steel rims
than with aluminum spokes.
Chalo
Ben C
[...]
> Does the discussion answer why MO's deliver the wrong lenghts? I guess
> so. Its kinda like the LBS telling you that's how it works when you
> know the LBS never rides a bike so how could the LBS know?
The MO ones you got were miles out so they were probably working with
the wrong numbers to start with, or thought you wanted 4x.
I bought my last set of spokes MO. You just typed the length you wanted
into a box on the website having worked it out yourself.
For Shimano and Campag hubs you can get the dimensions you need for the
calculators from their websites.
Shimano are quite annoying because they have a million different
variants of everything-- Deore, Deore LX, Deore XT, etc., etc. They're
probably mostly the same size anyway, but you have to look at the small
print. Mine's full name turned out to be "Deore XT M760".
Mavic also provided the ERD on their website.
Down here in Group 3 or 4, I'm just happy if the spokes I get are close
enough to the right length I can actually put the wheel together, but
you're probably right ERD minus a couple of mm is a good idea.
Ben C
> length's threaded down just as the nipple seated loosely into eyelet.
> From the software directions, maybe misread, it appeared to me that
> was the ERD, where the spoke threaded fully and at that same cosmic
> instant reached full Jobst Brandt Group One Wheel perfection seating
> down immovabbley into the eyelet. Ahhhhhh...
>
> But that's wrong. The ERD is from axle center to inside rim surface?
>
> AS SHELDON BROWN'S GLOSSARY:
> E.R.D.
> Effective Rim Diameter. This is the rim diameter measured at the
> nipple seats in the spoke holes.
That's what I thought it was too. But Brandt says it's that plus twice
the nipple head depth, and he should know.
But what are manufacturers actually quoting? Sometimes you get some
apparent discrepancy between the data in the calculators/spreadsheets
and the official manufacturer info.
Take the "Mavic XM317 Disc" for example. Mavic say "Spoke support
diameter: 536mm".
But spocalc.xls, the spreadsheet many people use, gives 538.5 for the
ERD for this rim. A few lines further up, next to the "X317 Disc", there
is the comment "ERD is Mavic's Nipple Seat Dia plus 3mm for nipples".
That explains it (although why the 0.5mm discrepancy? Perhaps they
measured the XM317 Disc rather than took the quoted value and added 3mm).
I wouldn't be surprised though if some manufacturers/vendors are quoting
a figure they're calling ERD when actually it's spoke support diameter.
Such details easily get confused.
Some spoke calculators (DT's for example http://www.dtswiss.com)
actually ask you for the nipple length. Who cares how long the nipple
is? What difference does that make, unless they're asking about the
thickness of the head and treating what they call "ERD" (which they also
ask for) as spoke support diameter and assuming that you want the spokes
to come all the way to the top of the nipples.
If ERD includes nipple head thickness *2, then what kind of nipple is
that? Add 3mm? If your nipples are fatter, should you subtract 3 and
then add the real thickness of the nipples you have?
I just used Mavic's spoke support diameters directly, I didn't add
anything for nipples, and the spokes came out fine. But this whole issue
is quite confusing.
I think spoke support diameter is a better metric to use and everyone
should just quote that. It's clearer what it means.
jim beam
absolutely perfect!
jim beam
>
> Ok we can flag this down. Beam is right. Forget the calc's database
> because the calc software is about to choose an ERD for you and right
> off the results aren't headed your way.
>
> The spoke calc is probbably Brandt's math child
did he invent geometry then???
> and that ERD is a
> spoke end "fully" inserted into the nipple, all threads used, no
> allowance for error or wear
what you're calling "wear" is almost certainly the plastic distortion of
the hub hole as the spoke beds in under tension.
> and so if your wheel building skills are
> building that type wheel that's your ERD. Why, practically anyone
> would build a wheel with an ERD that long? Is there a practical or
> strength advantage for limiting building alternatives thru striving
> toward math perfection?
some of this is tradition, but the remainder is practical. sufficient
length of spoke thread means a wheel that is much easier to lace - too
short is a real pain, even though it can take the load. too much thread
[too long spoke] means the spoke nipple binds and the spoke sticks out
to a point where it could puncture the tube [depending on rim]. the
practical solution therefore is a spoke ending at or about the point
where the spoke nipple ends. and that's really all there is to it.
>
> The Group 2 or wheel building slob like me needs an ERD or final
> result spoke end position ( FRSEP ) falling short of full thread
> use. leaving room for error, anomalies in the earth's rotational
> speed, gross stupidity, that kinda thing.
that's really not true. correct use of a spoke calculator gives you
exact results - a margin for anticipated error is not necessary.
>
> Does the discussion answer why MO's deliver the wrong lenghts?
in my experience, they deliver exactly what's ordered. if the order is
not right, well, there will be consequences for which the mo has zero
responsibility.
> I guess
> so. Its kinda like the LBS telling you that's how it works when you
> know the LBS never rides a bike so how could the LBS know?
a flight engineer knows exactly how a plane works, yet he never uses a
wrench.
datakoll
Beam writes!
"too much thread
[too long spoke] means the spoke nipple binds and the spoke sticks
out
to a point where it could puncture the tube [depending on rim]. the
practical solution therefore is a spoke ending at or about the point
where the spoke nipple ends. and that's really all there is to it.
if the length is specified at Andrew Muzi's point as an ERD located
spoke length
then the spoke is practically too long
caws when it is tightened
"the spoke nipple binds and the spoke sticks out
to a point where it could puncture the tube"
I give up on it.
jim beam
no, this is /after/ it's tightened. before tightening, correct length
spokes are nowhere near the ends of the spoke nipples.
A Muzi
The wheel shown is at 115kg and as tight as it will ever be.
http://www.yellowjersey.org/photosfromthepast/SPOKDEPT.JPG
datakoll
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
"no, this is /after/ it's tightened. before tightening, correct
length
spokes are nowhere near the ends of the spoke nipples. "
YES! but the tape measure from hub hole to inside rim surface plus
distance to the outside eyelet surface is the path of SPOKE LENGTH
measurement. off course the discussion is spoke length in nipple after
tightening to road torques. An ERD is not the final chosen length. I'd
say Andy Muzi's finish spoke length is a nice piece of work but to far
in for practical long distnace cycling. Around the block ok but not
over the road and over to Santa Fe.