# SPOKE LENGTH IN NIPPLE

Ben C? writes:

>>>>> "erd" is simple enough - it's what "effective" means that's
>>>>> unclear. maybe that's why mavic call it "spoke support" - since
>>>>> they clearly haven't read jobst's book and are untainted by its
>>>>> terminological inexactitudes.

>>> "erd" is calculation input. you decide the result you want it to
>>> give.

>> But the output is the spoke length, if I knew the spoke length I
>> could calculate the ERD, but I don't know the spoke length, so
>> which ERD do I choose?

> You decide what point in the rim cross-section you want the spoke
> ends to reach. Then you measure the distance from there to the
> corresponding opposite point on the other side. That's the ERD.

>> My point was, surely it's defined?

> It is defined, but in terms of what you personally want! This is
> what Jim Beam is saying, also Damon Rinard on the link posted
> earlier.

http://sheldonbrown.com/rinard/spocalc.htm

# "Effective Rim Diameter (ERD) is the diameter on which you want
# the ends of the spokes to lie. Most people prefer it near the
# end of the spoke nipple."

> But, in Sheldon's glossary, a slightly different definition:

http://www.sheldonbrown.com/gloss_e-f.html

# "Effective Rim Diameter. This is the rim diameter measured at
# the nipple seats in the spoke holes, plus the thickness of the
# two nipple heads. The E.R.D. is needed for calculating the
# correct spoke length."

> This second definition implies ERD is defined as distance between
> nipple seats. But according to the first definition it's only that
> distance if _that's how long you personally like your spokes_. Some
> people might add 3mm to that.

Not so. Both of these are essentially the distance over spoke nipple
ends measured across the diameter of the rim. Only the wording is
different.

>> Actually, I'm ****** and I'm going to bed, thoroughly confused
>> about whether a manufacturers ERD is to be trusted or is just a
>> number they dreamed up.

> It would be much better if manufacturers always just quoted spoke
> support diameter. Then you know what the number actually is supposed
> to correspond to and can add 3mm if you like longer spokes, or not
> if you don't.

That is not my perception of the dimension. You can do anything you
want with an ERD that spans the tops of spoke nipples, the place where
spokes should reach from the hub.

> If 3mm ended up getting added twice due to these misunderstandings
> the spokes could be too long by enough to cause a real problem.

3mm is roughly the height of a spoke nipple head, so it needs to be
added twice to the bed of the rim support surface, there being two
spoke nipples on the diameter.

Jobst Brandt

On Feb 3, 8:34 am, [email protected] wrote:
> Ben C? writes:
> >>>>> "erd" is simple enough - it's what "effective" means that's
> >>>>> unclear.  maybe that's why mavic call it "spoke support" - since
> >>>>> they clearly haven't read jobst's book and are untainted by its
> >>>>> terminological inexactitudes.
> >>> "erd" is calculation input.  you decide the result you want it to
> >>> give.
> >> But the output is the spoke length, if I knew the spoke length I
> >> could calculate the ERD, but I don't know the spoke length, so
> >> which ERD do I choose?

> > You decide what point in the rim cross-section you want the spoke
> > ends to reach. Then you measure the distance from there to the
> > corresponding opposite point on the other side. That's the ERD.
> >> My point was, surely it's defined?

> > It is defined, but in terms of what you personally want! This is
> > what Jim Beam is saying, also Damon Rinard on the link posted
> > earlier.

>
>      http://sheldonbrown.com/rinard/spocalc.htm
>
> #     "Effective Rim Diameter (ERD) is the diameter on which you want
> #     the ends of the spokes to lie.  Most people prefer it near the
> #     end of the spoke nipple."
>
> > But, in Sheldon's glossary, a slightly different definition:

>
>      http://www.sheldonbrown.com/gloss_e-f.html
>
> #     "Effective Rim Diameter.  This is the rim diameter measured at
> #     the nipple seats in the spoke holes, plus the thickness of the
> #     two nipple heads.  The E.R.D. is needed for calculating the
> #     correct spoke length."
>
> > This second definition implies ERD is defined as distance between
> > nipple seats.  But according to the first definition it's only that
> > distance if _that's how long you personally like your spokes_.  Some
> > people might add 3mm to that.

>
> Not so.  Both of these are essentially the distance over spoke nipple
> ends measured across the diameter of the rim.  Only the wording is
> different.
>
> >> Actually, I'm ****** and I'm going to bed, thoroughly confused
> >> about whether a manufacturers ERD is to be trusted or is just a
> >> number they dreamed up.

> > It would be much better if manufacturers always just quoted spoke
> > support diameter. Then you know what the number actually is supposed
> > to correspond to and can add 3mm if you like longer spokes, or not
> > if you don't.

>
> That is not my perception of the dimension.  You can do anything you
> want with an ERD that spans the tops of spoke nipples, the place where
> spokes should reach from the hub.
>
> > If 3mm ended up getting added twice due to these misunderstandings
> > the spokes could be too long by enough to cause a real problem.

>
> 3mm is roughly the height of a spoke nipple head, so it needs to be
> added twice to the bed of the rim support surface, there being two
> spoke nipples on the diameter.
>
> Jobst Brandt- Hide quoted text -
>
> - Show quoted text -

WHY NOT add 4mm just to be sure? only the WORDS are different?
now I understand why people complain about figuring taxs. then add the
1.5 mm fiddle factors...
not to mention AGAIN that the gathered experts refuse the question why
the spoke end should reach so far into the rim that the threading
bottoms out over at the spoke shaft....

Ben C wrote:
> On 2008-02-03, datakoll <[email protected]> wrote:
>> On Feb 2, 9:39ï¿½pm, datakoll <[email protected]> wrote:

> [...]
>> ach did that again JB! (ERD/2)-3mm=spoke length

>
> Of course not! To work out spoke length from ERD you need to know hub
> dimensions and number of crossings and do the proper formula, which is
> more complicated than that one.
>
> The question is what's your manufacturer quoting. If it's Mavic, they
> quote spoke support diameter, so just use that. Don't subtract 3mm.
>
> If it's someone else and they quote "ERD" you have a problem because who
> knows whether they added a bit to the spoke support diameter to get ERD
> or not. It depends on their personal preference.
>
> Best advice is just go with what the rim manufacturer quotes. If they
> think you need spokes a little bit longer than you do just live with it.
> If you add/subtract 3mm trying to second-guess what they mean by ERD you
> risk doubling the error.

well said.

On 2008-02-03, [email protected] <[email protected]> wrote:
> Ben C? writes:

[...]
> http://sheldonbrown.com/rinard/spocalc.htm
>
> # "Effective Rim Diameter (ERD) is the diameter on which you want
> # the ends of the spokes to lie. Most people prefer it near the
> # end of the spoke nipple."
>
>> But, in Sheldon's glossary, a slightly different definition:

>
> http://www.sheldonbrown.com/gloss_e-f.html
>
> # "Effective Rim Diameter. This is the rim diameter measured at
> # the nipple seats in the spoke holes, plus the thickness of the
> # two nipple heads. The E.R.D. is needed for calculating the
> # correct spoke length."
>
>> This second definition implies ERD is defined as distance between
>> nipple seats. But according to the first definition it's only that
>> distance if _that's how long you personally like your spokes_. Some
>> people might add 3mm to that.

>
> Not so. Both of these are essentially the distance over spoke nipple
> ends measured across the diameter of the rim. Only the wording is
> different.

You're right, I missed the bit "plus the thickness of the two nipple
heads". The definitions are exactly the same, and the same as one you
gave earlier.

Sorry for being so stupid.

datakoll said:
On Feb 3, 8:34*am, [email protected] wrote:
> Ben C? writes:
> >>>>> "erd" is simple enough - it's what "effective" means that's
> >>>>> unclear. *maybe that's why mavic call it "spoke support" - since
> >>>>> they clearly haven't read jobst's book and are untainted by its
> >>>>> terminological inexactitudes.
> >>> "erd" is calculation input. *you decide the result you want it to
> >>> give.
> >> But the output is the spoke length, if I knew the spoke length I
> >> could calculate the ERD, but I don't know the spoke length, so
> >> which ERD do I choose?

> > You decide what point in the rim cross-section you want the spoke
> > ends to reach. Then you measure the distance from there to the
> > corresponding opposite point on the other side. That's the ERD.
> >> My point was, surely it's defined?

> > It is defined, but in terms of what you personally want! This is
> > what Jim Beam is saying, also Damon Rinard on the link posted
> > earlier.

>
> * * *http://sheldonbrown.com/rinard/spocalc.htm
>
> # * * "Effective Rim Diameter (ERD) is the diameter on which you want
> # * * the ends of the spokes to lie. *Most people prefer it near the
> # * * end of the spoke nipple."
>
> > But, in Sheldon's glossary, a slightly different definition:

>
> * * *http://www.sheldonbrown.com/gloss_e-f.html
>
> # * * "Effective Rim Diameter. *This is the rim diameter measured at
> # * * the nipple seats in the spoke holes, plus the thickness of the
> # * * two nipple heads. *The E.R.D. is needed for calculating the
> # * * correct spoke length."
>
> > This second definition implies ERD is defined as distance between
> > nipple seats. *But according to the first definition it's only that
> > distance if _that's how long you personally like your spokes_. *Some
> > people might add 3mm to that.

>
> Not so. *Both of these are essentially the distance over spoke nipple
> ends measured across the diameter of the rim. *Only the wording is
> different.
>
> >> Actually, I'm ****** and I'm going to bed, thoroughly confused
> >> about whether a manufacturers ERD is to be trusted or is just a
> >> number they dreamed up.

> > It would be much better if manufacturers always just quoted spoke
> > support diameter. Then you know what the number actually is supposed
> > to correspond to and can add 3mm if you like longer spokes, or not
> > if you don't.

>
> That is not my perception of the dimension. *You can do anything you
> want with an ERD that spans the tops of spoke nipples, the place where
> spokes should reach from the hub.
>
> > If 3mm ended up getting added twice due to these misunderstandings
> > the spokes could be too long by enough to cause a real problem.

>
> 3mm is roughly the height of a spoke nipple head, so it needs to be
> added twice to the bed of the rim support surface, there being two
> spoke nipples on the diameter.
>
> Jobst Brandt- Hide quoted text -
>
> - Show quoted text -

WHY NOT add 4mm just to be sure? only the WORDS are different?
now I understand why people complain about figuring taxs. then add the
1.5 mm fiddle factors...
not to mention AGAIN that the gathered experts refuse the question why
the spoke end should reach so far into the rim that the threading
bottoms out over at the spoke shaft....
Look at the illustration on the Rinard section of Sheldon Brown's site that vaious people told you about. This illustration includes using the nipples you will use and the rim you will use (No calculations of estimates). You position the spokes in the nipples as you would like them to end up after final tensioning. The length you get is the Effective Rim Diameter. If you follow the illustration and the steps given, you will have the actual ERD fro the particular rim and nipple combination. When you plug in that ERD into your spoke calcualtion you will get the correct answer for spoke lengths every time and with every crossing pattern.

On Feb 3, 10:00Â am, jim beam <[email protected]> wrote:
> Ben C wrote:
> > On 2008-02-03, datakoll <[email protected]> wrote:
> >> On Feb 2, 9:39ï¿½pm, datakoll <[email protected]> wrote:

> > [...]
> >> ach did that again JB! Â (ERD/2)-3mm=spoke length

>
> > Of course not! To work out spoke length from ERD you need to know hub
> > dimensions and number of crossings and do the proper formula, which is
> > more complicated than that one.

>
> > The question is what's your manufacturer quoting. If it's Mavic, they
> > quote spoke support diameter, so just use that. Don't subtract 3mm.

>
> > If it's someone else and they quote "ERD" you have a problem because who
> > knows whether they added a bit to the spoke support diameter to get ERD
> > or not. It depends on their personal preference.

>
> > Best advice is just go with what the rim manufacturer quotes. If they
> > think you need spokes a little bit longer than you do just live with it.
> > If you add/subtract 3mm trying to second-guess what they mean by ERD you
> > risk doubling the error.

>
> well said.- Hide quoted text -
>
> - Show quoted text -

what is SPOKE SUPPORT DIAMETER? What's Mavic's address for their
definiton of SSD?

On 2008-02-03, datakoll <[email protected]> wrote:
> On Feb 3, 10:00 am, jim beam <[email protected]> wrote:
>> Ben C wrote:

[...]
>> > The question is what's your manufacturer quoting. If it's Mavic, they
>> > quote spoke support diameter, so just use that. Don't subtract 3mm.

[...]
> what is SPOKE SUPPORT DIAMETER?

I assume it means diameter between the points on the rim where the
nipples sit.

i.e. ERD (as defined by Brandt and Sheldon) minus about 3mm.

But you ask a good question, because I don't know for sure what they
mean by it.

> What's Mavic's address for their definiton of SSD?

Don't know, but if you get hold of them and find out the exact
definition of SSD, post it here.

On Feb 3, 1:31 pm, Ben C <[email protected]> wrote:
> On 2008-02-03, datakoll <[email protected]> wrote:
>
> > On Feb 3, 10:00 am, jim beam <[email protected]> wrote:
> >> Ben C wrote:

> [...]
> >> > The question is what's your manufacturer quoting. If it's Mavic, they
> >> > quote spoke support diameter, so just use that. Don't subtract 3mm.

> [...]
> > what is SPOKE SUPPORT DIAMETER?

>
> I assume it means diameter between the points on the rim where the
> nipples sit.
>
> i.e. ERD (as defined by Brandt and Sheldon) minus about 3mm.
>
> But you ask a good question, because I don't know for sure what they
> mean by it.
>
> > What's Mavic's address for their definiton of SSD?

>
> Don't know, but if you get hold of them and find out the exact
> definition of SSD, post it here.

Spoke Calc can incorporate a spoke/nipple/rim blowup showing where the
ERD is, how many spoke threads the ERD uses, how many are left for
wear and estimate wear, elbow stretch, anomaly and relating the odd
happenings to spoke thread availability when ERD is used as a real
time spoke end calculation (without deduction).

an oversimplification form an engineer ?
I call for truth in spoke calc and the engineer cries out for
continued obfucstaion?
A graphic is an educational tool not oly for the consumer but MO and
LBS staff unable to enter data into spoke clcs and ship correct
lengths.
THE ERD DOESN'T WORK! THE ERD USES 90% of available spoke threading
just to satisfy GOD ERD AND THE ERD ELITISTS.
seriously Jim, using up threading to satisfy a programable math model
is self defeating.

datakoll wrote:
>
> an oversimplification form an engineer ?
> I call for truth in spoke calc and the engineer cries out for
> continued obfucstaion?
> A graphic is an educational tool not oly for the consumer but MO and
> LBS staff unable to enter data into spoke clcs and ship correct
> lengths.
> THE ERD DOESN'T WORK! THE ERD USES 90% of available spoke threading
> just to satisfy GOD ERD AND THE ERD ELITISTS.
> seriously Jim, using up threading to satisfy a programable math model
> is self defeating.

fact: regardless of what your fears or opinions on this subject,
literally millions of wheels, over the course of >100 years, have been
built with this formula. with complete success. if you take nothing
else away from this conversation, let that fact be the one thing you can
accept.

and cut them to length yourself after building.

On Feb 5, 11:54 pm, jim beam <[email protected]> wrote:
> datakoll wrote:
>
> > an oversimplification form an engineer ?
> > I call for truth in spoke calc and the engineer cries out for
> > continued obfucstaion?
> > A graphic is an educational tool not oly for the consumer but MO and
> > LBS staff unable to enter data into spoke clcs and ship correct
> > lengths.
> > THE ERD DOESN'T WORK! THE ERD USES 90% of available spoke threading
> > just to satisfy GOD ERD AND THE ERD ELITISTS.
> > seriously Jim, using up threading to satisfy a programable math model
> > is self defeating.

>
> fact: regardless of what your fears or opinions on this subject,
> literally millions of wheels, over the course of >100 years, have been
> built with this formula.  with complete success.  if you take nothing
> else away from this conversation, let that fact be the one thing you can
> accept.
>
> and cut them to length yourself after building.

datakoll wrote:
> On Feb 5, 11:54ï¿½pm, jim beam <[email protected]> wrote:
>> datakoll wrote:
>>
>>> an oversimplification form an engineer ?
>>> I call for truth in spoke calc and the engineer cries out for
>>> continued obfucstaion?
>>> A graphic is an educational tool not oly for the consumer but MO and
>>> LBS staff unable to enter data into spoke clcs and ship correct
>>> lengths.
>>> THE ERD DOESN'T WORK! THE ERD USES 90% of available spoke threading
>>> just to satisfy GOD ERD AND THE ERD ELITISTS.
>>> seriously Jim, using up threading to satisfy a programable math model
>>> is self defeating.

>> fact: regardless of what your fears or opinions on this subject,
>> literally millions of wheels, over the course of >100 years, have been
>> built with this formula. ï¿½with complete success. ï¿½if you take nothing
>> else away from this conversation, let that fact be the one thing you can
>> accept.
>>
>> and cut them to length yourself after building.

>

why would it be weaker on the shaft than on the bit where the spoke
nipple is connected?

On Feb 6, 9:23Â am, jim beam <[email protected]> wrote:
> datakoll wrote:
> > On Feb 5, 11:54ï¿½pm, jim beam <[email protected]> wrote:
> >> datakoll wrote:

>
> >>> an oversimplification form an engineer ?
> >>> I call for truth in spoke calc and the engineer cries out for
> >>> continued obfucstaion?
> >>> A graphic is an educational tool not oly for the consumer but MO and
> >>> LBS staff unable to enter data into spoke clcs and ship correct
> >>> lengths.
> >>> THE ERD DOESN'T WORK! THE ERD USES 90% of available spoke threading
> >>> just to satisfy GOD ERD AND THE ERD ELITISTS.
> >>> seriously Jim, using up threading to satisfy a programable math model
> >>> is self defeating.
> >> fact: regardless of what your fears or opinions on this subject,
> >> literally millions of wheels, over the course of >100 years, have been
> >> built with this formula. ï¿½with complete success. ï¿½if you take nothing
> >> else away from this conversation, let that fact be the one thing you can
> >> accept.

>
> >> and cut them to length yourself after building.

>

>
> why would it be weaker on the shaft than on the bit where the spoke
> nipple is connected?- Hide quoted text -
>
> - Show quoted text -

THIS IS WHERE THE DUCK FALLS FROM THE CEILING !

>> datakoll wrote:
>>> an oversimplification form an engineer ?
>>> I call for truth in spoke calc and the engineer cries out for
>>> continued obfucstaion?
>>> A graphic is an educational tool not oly for the consumer but MO and
>>> LBS staff unable to enter data into spoke clcs and ship correct
>>> lengths.
>>> THE ERD DOESN'T WORK! THE ERD USES 90% of available spoke threading
>>> just to satisfy GOD ERD AND THE ERD ELITISTS.
>>> seriously Jim, using up threading to satisfy a programable math model
>>> is self defeating.

> jim beam <[email protected]> wrote:
>> fact: regardless of what your fears or opinions on this subject,
>> literally millions of wheels, over the course of >100 years, have been
>> built with this formula. with complete success. if you take nothing
>> else away from this conversation, let that fact be the one thing you can
>> accept.
>> and cut them to length yourself after building.

datakoll wrote:

Maybe. But since the overwhelming bulk of breakage is at the head, what
does it matter? Threaded portion is strong enough.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

datakoll wrote:
> THIS IS WHERE THE DUCK FALLS FROM THE CEILING !

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

yeah and the Duck Sez: ERD and spoke threading leading to metal
fatigue for 1960-1980 metallurgy/manufacturing methods? That ERD would
eliminate this hypothetical weakness with full insertion up to total
thread use (for no otherwise good reason)

datakoll wrote:
>
> yeah and the Duck Sez: ERD and spoke threading leading to metal
> fatigue for 1960-1980 metallurgy/manufacturing methods? That ERD would
> eliminate this hypothetical weakness with full insertion up to total
> thread use (for no otherwise good reason)

the spoke nipple has to be threaded with the spokes slack as well as
tight. and accommodate bedding in. what is sufficient to be engaged
when slack needs to be adjusted out, and thus, threaded up the spoke nipple.

try building with spokes that are too short and see how you enjoy the
experience. or not.

datakoll aka gene daniels wrote:
> ...
> THIS IS WHERE THE DUCK FALLS FROM THE CEILING !

Do bicycle helmets provide adequate protection against falling ducks?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

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