ERD...yet another thread

..ERD is the standard length you use to
DEDUCT from to order spokes

measuring for double walls takes NIQ+10 where we arrive at 0
insert spoke into rim, magic tape insertion at rim inside entry hole
for nipple head reach, then for slot base reach, then for 1.5mm short
of slot base reach.
OR tape spoke shaft when spoke reachs inside rim eyelet (the grommet
reinforcement)
WRITE THE NUMBERS DOWN WITH ASSCOCIATED DIAGRAM IN YOUR LOG BOOK.
then insert spoke into nipple to threading: tape insertion on spoke.
measure the short end.
then thread spoke onto nipple until spoke arrives at slot base. tape
spoke shaft and measure short end.
WRITE THE NUMBERS DOWN IN YOUR LOG BOOK.
you now have a spoke length table. Use the table for tilting at ERD.
841
ERD is snot spoke length, spoke length is AESL. Rinard and Brandt,
obviously highly intelligent people continue chanting ERD like mary
had a little lamb is spoke length until people of normal
intelligence
believe that, to their error and consternation.
Clearing the problem off the boards using magic tape and AESL is
similar to Gates' ascesnion to world's second richest man, having
soooooo much money he gave it to Africans soooo we can have more
Africans.
MP,
gnaw. you missed the point. Brandt sez ERD is his idea. ERD
establishes ONE MEASUREMENT STANDRAD for one wheel combination, not 4
standradrs for one wheel combination.
BUTBUTBUT ERD is snot AESL. AESL is the small range of engaged
threading used for ordering spokes and building the wheel. AESL=ERD-
SDR (standard deduction range)
ERD is software's spoke calc standard hypotenuse length as a math
constant. (maybe also a disease)
Its snot the length you use to order spokes. ERD is the standard
length you use to
DEDUCT from to order spokes
Yeah. the dishing beam is essential and a basic wheel building tool.
Insert spokes, seat, gives correct dish. A red oak or better beam
should lean in every shop's corner.
almost. ERD is an hypotenuse not a diameter. That's why we're
suffering thru the grinding interface of language and math here thru
god software and priests.
try using magic tape for defining threading position inside the
nipple. The threading engagment of spoke and nipple related to actual
effective spoke length (AESL) NOT ERD is the measurement we're after
here.
That's a refinment of what you wrote. right?

the mezzanine is on your left

datakoll said:

.ERD is the standard length you use to
DEDUCT from to order spokes

Sounds basic enough, but DEDUCT implies simple subtraction. It's not
that easy. Here's the formula I used in a spreadsheet I put together
many, many years ago to calculate spoke lengths:

=D11/2+0.998*(SQRT(D6^2/4+D7^2/4-D6*D7/2*COS(PI()*4*D9/D8)+D10^2))

where: D6 is what we refer to as ERD. I just noticed that in the
spreadsheet I refer to D6 as "Diameter of rim at spoke holes". Clearly
I put the spreadsheet together before I'd ever heard the term ERD.

BTW, my original spoke length spreadsheet was done so long ago I used
Lotus 123. The above is from an Excel conversion.

YABTW, if anyone wants a copy of my simple spreadsheet send an email
and I'll forward it. It's not as spiffy as spocalc and you have to
provide all the measurements yourself, but it gets spokes of the
correct length. :-)

--
jeverett3<AT>sbcglobal<DOT>net (John V. Everett)

John Everett said:

Should ERD actually be the diameter of the circle defined by the ends
of the spokes in the built wheel?

Yes.

Quoted message said:

If so, should the end of the spokes
theoretically be even with the top of the nipple, or buried somewhere
inside the nipple?

Ideally, spoke ends should be even with the top of the nipple.

You should try to get the spoke length right to within a mm.

Art Harris

ART really, is ERD a diameter? spoke clac is used to arrive at the
diameter of a circle?

John is pulling our leg on his math trip.

take the rim, the spoke, and the nipple - any long enough to go thru
the rim with rim and hub mounted ona dishing beam

and fool with it as in the above instructions.

ERD-Standard Deduction (the threading arrangement the builder will
work out to his satisfaction NOT RINARD or JB or EUCLID or GODEL) =
AESL - useable spoke length

ERD isnot useable spoke length

Thank you for the wheelbuilding instructions below, Gene. I have
ordered from DT Swiss a thousand rims, with enough spokes and tools
and accessories to build a thousand wheels. Do you think that with
your instructions I might manage to build one wheel that rolls?

Whether the mezzanine is on your right or on your left depends on the
direction from which you arrive. You can't get there from here.

Yours admiringly,

A humble aspirant Obfuskator

datakoll said:

.ERD is the standard  length you use to
DEDUCT from to order spokes

measuring for double walls takes NIQ+10 where we arrive at 0
insert spoke into rim, magic tape insertion at rim inside entry hole
for nipple head reach, then for slot base reach, then for 1.5mm short
of slot base reach.
OR tape spoke shaft when spoke reachs inside rim eyelet (the grommet
reinforcement)
WRITE THE NUMBERS DOWN WITH ASSCOCIATED DIAGRAM IN YOUR LOG BOOK.
then insert spoke into nipple to threading: tape insertion on spoke.
measure the short end.
then thread spoke onto nipple until spoke arrives at slot base. tape
spoke shaft and measure short end.
WRITE THE NUMBERS DOWN IN YOUR LOG BOOK.
you now have a spoke length table. Use the table for tilting at ERD.
841
ERD is snot spoke length, spoke length is AESL. Rinard and Brandt,
obviously highly intelligent people continue chanting ERD like mary
had a little lamb is spoke length until  people of normal
intelligence
believe that, to their error and consternation.
Clearing the problem off the boards using magic tape and AESL is
similar to Gates' ascesnion to world's second richest man, having
soooooo much money he gave it to Africans soooo we can have more
Africans.
MP,
gnaw. you missed the point. Brandt sez ERD is his idea. ERD
establishes ONE MEASUREMENT STANDRAD for one wheel combination, not 4
standradrs for one wheel combination.
BUTBUTBUT ERD is snot AESL. AESL is the small range of engaged
threading used for ordering spokes and building the wheel. AESL=ERD-
SDR (standard deduction range)
ERD is software's spoke calc standard hypotenuse length as a math
constant. (maybe also a disease)
Its snot the length you use to order spokes. ERD is the standard
length you use to
DEDUCT from to order spokes
Yeah. the dishing beam is essential and a basic wheel building tool.
Insert spokes, seat, gives correct dish. A red oak or better beam
should  lean in every shop's corner.
almost. ERD is an hypotenuse not a diameter. That's why we're
suffering thru the grinding interface of language and math here thru
god software and priests.
try using magic tape for defining threading position inside the
nipple. The threading engagment of spoke and nipple related to actual
effective spoke length (AESL) NOT ERD is the measurement we're after
here.
That's a refinment of what you wrote. right?

the mezzanine is on your left

Andre Jute said:

Thank you for the wheelbuilding instructions below, Gene. I have
ordered from DT Swiss a thousand rims, with enough spokes and tools
and accessories to build a thousand wheels. Do you think that with
your instructions I might manage to build one wheel that rolls?

Whether the mezzanine is on your right or on your left depends on the
direction from which you arrive. You can't get there from here.

Yours admiringly,

A humble aspirant Obfuskator

datakoll said:

.ERD is the standard  length you use to
DEDUCT from to order spokes

Quoted message said:

measuring for double walls takes NIQ+10 where we arrive at 0
insert spoke into rim, magic tape insertion at rim inside entry hole
for nipple head reach, then for slot base reach, then for 1.5mm short
of slot base reach.
OR tape spoke shaft when spoke reachs inside rim eyelet (the grommet
reinforcement)
WRITE THE NUMBERS DOWN WITH ASSCOCIATED DIAGRAM IN YOUR LOG BOOK.
then insert spoke into nipple to threading: tape insertion on spoke.
measure the short end.
then thread spoke onto nipple until spoke arrives at slot base. tape
spoke shaft and measure short end.
WRITE THE NUMBERS DOWN IN YOUR LOG BOOK.
you now have a spoke length table. Use the table for tilting at ERD.
841
ERD is snot spoke length, spoke length is AESL. Rinard and Brandt,
obviously highly intelligent people continue chanting ERD like mary
had a little lamb is spoke length until  people of normal
intelligence
believe that, to their error and consternation.
Clearing the problem off the boards using magic tape and AESL is
similar to Gates' ascesnion to world's second richest man, having
soooooo much money he gave it to Africans soooo we can have more
Africans.
MP,
gnaw. you missed the point. Brandt sez ERD is his idea. ERD
establishes ONE MEASUREMENT STANDRAD for one wheel combination, not 4
standradrs for one wheel combination.
BUTBUTBUT ERD is snot AESL. AESL is the small range of engaged
threading used for ordering spokes and building the wheel. AESL=ERD-
SDR (standard deduction range)
ERD is software's spoke calc standard hypotenuse length as a math
constant. (maybe also a disease)
Its snot the length you use to order spokes. ERD is the standard
length you use to
DEDUCT from to order spokes
Yeah. the dishing beam is essential and a basic wheel building tool.
Insert spokes, seat, gives correct dish. A red oak or better beam
should  lean in every shop's corner.
almost. ERD is an hypotenuse not a diameter. That's why we're
suffering thru the grinding interface of language and math here thru
god software and priests.
try using magic tape for defining threading position inside the
nipple. The threading engagment of spoke and nipple related to actual
effective spoke length (AESL) NOT ERD is the measurement we're after
here.
That's a refinment of what you wrote. right?

Quoted message said:

the mezzanine is on your left- Hide quoted text -

- Show quoted text -

built muh first wheel without instructions.
then with Brwon's instructions but spoke clac lengths' I nevah bilt
another right off again
from which frustration led to the current hoooha.
IF the beam is built, and the builder fiddles with threading,
recording his measurement's in a retrievable fashion, tries
experimental spokes on the beam AND consults RINARD - DT et al then
urine.
As you can see, the approach to Rinard is incomplete. Addition of HOW
TO MEASURE articles obviously doesnot help overcome the problem JB-
Rinard et al brought on us: that ERD is spoke length when ERD is a
math constant for spoke length(s). An odd innocent twist to a semantic
pron]bl;em? Not with the intelligence carrying the obfuscation.

John Everett said:

Even though I've now ordered the spokes I was writing about when I
started the ERD thread, I still never received a clear answer to my
original question. Let me rephrase:

Should ERD actually be the diameter of the circle defined by the ends
of the spokes in the built wheel?

Yes, that is exactly what it is, qua an input to the calculators.

In other words, suppose you want opposite spoke ends 595mm apart. Then
put 595mm in the formula, and you should get a spoke length that will
give you opposing spoke ends 595mm apart in the finished wheel.

Quoted message said:

If so, should the end of the spokes theoretically be even with the top
of the nipple, or buried somewhere inside the nipple? If buried,
should they be even with the outside surface of the rim holes, or even
with the bottom of the screwdriver slot?

That's a matter of personal preference. I think datakoll prefers his
coming up as far as about the bottom of the screwdriver slot.

That's pretty much ideal in terms of the final position, but others may
prefer the spokes 1mm or 1.5mm longer than that because it may make
lacing easier-- more threads to grab hold of while the spokes are all
still very loose.

Quoted message said:

Note that we're talking about millimeter differences here, which
strikes me as a bit like discussing the number of angels the can dance
on the head of a pin. ;-)

Mavic for example don't quote an ERD, but a spoke support diameter. This
is the distance between nipple seats, and is therefore about 3mm shorter
than the ERD as defined by Brandt. But it's a perfectly good spoke
length to just use without adding 3mm.

If you're like datakoll and like your spokes a bit shorter, you might be
tempted to subtract 3mm from a quoted ERD to get the spoke support
diameter and use that so your spokes come up to the bottom of the nipple
heads.

The problem is can you be sure it's really an ERD in the strict
Brandtian sense and not a spoke support diameter? Not everyone is so
careful with these terms. As far as many people are concerned, there is
just the length you want: it's just a number, and what you want to call
it ("ERD", "spoke support diameter", etc.) is mere technobabble. It
doesn't always occur to the man in the LBS to wonder whether sir would
like his spokes to run to the bottom or to the top of the nipples.

That's why if you find a number printed somewhere just go with that--
the worst that can happen is your spokes are a harmless 3mm from your
personal preference. But if you add 3mm or subtract 3mm thinking you
know what you're doing, but jump the wrong way, you could be 6mm out,
which could be a bit too far.

Quoted message said:

I've re-rimmed wheels with rims that were
5mm larger in published ERD than the originals without problems. Makes
me wonder how many nipple threads actually need to be engaged to build
a safe wheel.

I should think certainly not all of them.

Quoted message said:

I'm guessing from Jobst's response in my OP's thread that ERD is
precisely defined in "The Bicycle Wheel", but I've managed to build a
number of wheels without ever reading it.

He defines it as the length to get the spoke to the top of the nipple.

datakoll said:

ART really, is ERD a diameter? spoke clac is used to arrive at the
diameter of a circle?

No, spoke clac gives you the spoke length _from_ the diameter of a
circle. ERD is an input, and is something you can reasonably easily
measure with a piece of string.

The only reason for deducting a bit from ERD is because you like your
spokes a bit shorter.

Quoted message said:

John is pulling our leg on his math trip.

take the rim, the spoke, and the nipple - any long enough to go thru
the rim with rim and hub mounted ona dishing beam

and fool with it as in the above instructions.

ERD-Standard Deduction (the threading arrangement the builder will
work out to his satisfaction NOT RINARD or JB or EUCLID or GODEL) =
AESL - useable spoke length

ERD isnot useable spoke length

Ben C said:

datakoll said:

ART really, is ERD a diameter? spoke clac is used to arrive at the
diameter of a circle?

No, spoke clac gives you the spoke length _from_ the diameter of a
circle. ERD is an input, and is something you can reasonably easily
measure with a piece of string.

The only reason for deducting a bit from ERD is because you like your
spokes a bit shorter.

Quoted message said:

John is pulling our leg on his math trip.

Quoted message said:

take the rim, the spoke, and the nipple - any long enough to go thru
the rim with rim and hub mounted ona dishing beam

Quoted message said:

and fool with it as in the above instructions.

Quoted message said:

ERD-Standard Deduction (the threading arrangement  the builder will
work out to his satisfaction NOT RINARD or JB or EUCLID or GODEL) =
AESL - useable spoke length

Quoted message said:

ERD isnot useable spoke length- Hide quoted text -

- Show quoted text -

OK one more time for the slow

ERD is a math constant ignoring the varieties of human and non-human
experience with spoke nipples and spoke threads. ERD is the real time
hypotenuse of a theorectic circle described by a bicycle wheel. ERD is
the measurement from a cone's point to the cone's base minus the cone
decribed by a cone who who whose base is formed by spoke hub holes and
following the path of the larger cone, the distance to a theorectic
point above axle center.

ERD as a real time measurement fails BECAUSE spokes and nipples do
not or should not thread to the nipple head.

A Muzi said:

datakoll wrote:

-snip ERD redux-

Quoted message said:

urine-
As you can see, the approach to Rinard is incomplete. Addition of HOW
TO MEASURE articles obviously doesnot help overcome the problem JB-
Rinard et al brought on us: that ERD is spoke length when ERD is a
math constant for spoke length(s). An odd innocent twist to a semantic
pron]bl;em? Not with the intelligence carrying the obfuscation.

We calc and build wheels all day long and, believe me, we just cannot
afford to be wrong about a spoke length. Whatever frustration you have
would be shared _plus_ we'd lose the time of a wheel build. And time, as
you know, is money.

For a wheelbuilder doing several pairs per day of various road and track
wheels, a standard software tool such as "spocalc2" and a set of rim
measuring gauges[1] are all that's needed. Spoke length turns out, in
real life, to be a trivial and quick calculation.

For the dedicated home builder, I am sympathetic to the various
impediments to selecting a spoke length. Good failsafe methods include:
*Buying spokes when you buy the rims, making the vendor responsible
*Asking the spoke vendor to do a calculation for you
*Asking any of the many wheelbuilders who frequent here to calc for you.
*making a set of rim gauges, measuring your hubs and using spocalc2.

An alternate method is to nearly build with the wrong length spokes and
interpolate which, it seems, may work just fine for you now!

I hesitate to mention (but I will, here goes!) that various
wheelbuilders have distinct preferences as to whether the spoke ends at
the inside edge of the rim, at the outer end of the nipple or somewhere
in between. Functionally, across that 2mm range, it matters not; any are
just fine.

[1] two 350mm welding rods each with a 2mm washer brazed flush at the end.
--
Andrew Muziwww.yellowjersey.org
Open every day since 1 April, 1971

Andy Muzi perspective as LBS owner and my perspective as Group Two
amatuer wheel builder are disimilar. Muzi knows what he's doing and
the wheels are his repsonsibility but the wheels are not his wheels.
when wheels leave Yellow Jersey, the wheels are the responsibility of
the owner.
I don't know what I'm doing and the wheels are my wheels come hell or
high water.
There are more of me than there are of Muzi but Muzi is responsible
for more wheels-which is a good deal for the planet.
Andrew's solution to spoke length IS NOT ERD. Andy's photo for the
first run in over ERD clear;y showed a spoke short of the nipples slot
base-waaaaaaaay down the road from the nipple's head.

My deal here is snot selling wheels to the non wheel building publick.
My deal is spreading some education on ERD thru RBT after an expert
(which is another difference, I gotta deal with THE EXPERT and Muzi is
the expert) sent the Nth batch of incorrect spoke lengths then swore
up and down that Rinard and Godel vouched his lengths were the right
lengths.

I recommended that Rinard change his evil ways avoiding further
inconvenience for the novice wheel builder before we get out there and
burnum out.

datakoll wrote:
-snip ERD redux-

Quoted message said:

urine-
As you can see, the approach to Rinard is incomplete. Addition of HOW
TO MEASURE articles obviously doesnot help overcome the problem JB-
Rinard et al brought on us: that ERD is spoke length when ERD is a
math constant for spoke length(s). An odd innocent twist to a semantic
pron]bl;em? Not with the intelligence carrying the obfuscation.

We calc and build wheels all day long and, believe me, we just cannot
afford to be wrong about a spoke length. Whatever frustration you have
would be shared _plus_ we'd lose the time of a wheel build. And time, as
you know, is money.

For a wheelbuilder doing several pairs per day of various road and track
wheels, a standard software tool such as "spocalc2" and a set of rim
measuring gauges[1] are all that's needed. Spoke length turns out, in
real life, to be a trivial and quick calculation.

For the dedicated home builder, I am sympathetic to the various
impediments to selecting a spoke length. Good failsafe methods include:
*Buying spokes when you buy the rims, making the vendor responsible
*Asking the spoke vendor to do a calculation for you
*Asking any of the many wheelbuilders who frequent here to calc for you.
*making a set of rim gauges, measuring your hubs and using spocalc2.

An alternate method is to nearly build with the wrong length spokes and
interpolate which, it seems, may work just fine for you now!

I hesitate to mention (but I will, here goes!) that various
wheelbuilders have distinct preferences as to whether the spoke ends at
the inside edge of the rim, at the outer end of the nipple or somewhere
in between. Functionally, across that 2mm range, it matters not; any are
just fine.

[1] two 350mm welding rods each with a 2mm washer brazed flush at the end.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

-snip ERD redux-

datakoll said:

built muh first wheel without instructions.
then with Brwon's instructions but spoke clac lengths' I nevah bilt
another right off again
from which frustration led to the current hoooha.
IF the beam is built, and the builder fiddles with threading,
recording his measurement's in a retrievable fashion, tries
experimental spokes on the beam AND consults RINARD - DT et al then
urine.
As you can see, the approach to Rinard is incomplete. Addition of HOW
TO MEASURE articles obviously doesnot help overcome the problem JB-
Rinard et al brought on us: that ERD is spoke length when ERD is a
math constant for spoke length(s). An odd innocent twist to a semantic
pron]bl;em? Not with the intelligence carrying the obfuscation.

We calc and build wheels all day long and, believe me, we just cannot
afford to be wrong about a spoke length. Whatever frustration you have
would be shared _plus_ we'd lose the time of a wheel build. And time, as
you know, is money.

For a wheelbuilder doing several pairs per day of various road and track
wheels, a standard software tool such as "spocalc2" and a set of rim
measuring gauges[1] are all that's needed. Spoke length turns out, in
real life, to be a trivial and quick calculation.

For the dedicated home builder, I am sympathetic to the various
impediments to selecting a spoke length. Good failsafe methods include:
*Buying spokes when you buy the rims, making the vendor responsible
*Asking the spoke vendor to do a calculation for you
*Asking any of the many wheelbuilders who frequent here to calc for you.
*making a set of rim gauges, measuring your hubs and using spocalc2.

An alternate method is to nearly build with the wrong length spokes and
interpolate which, it seems, may work just fine for you now!

I hesitate to mention (but I will, here goes!) that various
wheelbuilders have distinct preferences as to whether the spoke ends at
the inside edge of the rim, at the outer end of the nipple or somewhere
in between. Functionally, across that 2mm range, it matters not; any are
just fine.

[1] two 350mm welding rods each with a 4mm washer brazed flush at the end.

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

Ben C said:

John Everett said:

Even though I've now ordered the spokes I was writing about when I
started the ERD thread, I still never received a clear answer to my
original question. Let me rephrase:

Should ERD actually be the diameter of the circle defined by the ends
of the spokes in the built wheel?

Yes, that is exactly what it is, qua an input to the calculators.

In other words, suppose you want opposite spoke ends 595mm apart. Then
put 595mm in the formula, and you should get a spoke length that will
give you opposing spoke ends 595mm apart in the finished wheel.

Quoted message said:

If so, should the end of the spokes theoretically be even with the top
of the nipple, or buried somewhere inside the nipple? If buried,
should they be even with the outside surface of the rim holes, or even
with the bottom of the screwdriver slot?

That's a matter of personal preference. I think datakoll prefers his
coming up as far as about the bottom of the screwdriver slot.

That's pretty much ideal in terms of the final position, but others may
prefer the spokes 1mm or 1.5mm longer than that because it may make
lacing easier-- more threads to grab hold of while the spokes are all
still very loose.

Quoted message said:

Note that we're talking about millimeter differences here, which
strikes me as a bit like discussing the number of angels the can dance
on the head of a pin. ;-)

Mavic for example don't quote an ERD, but a spoke support diameter. This
is the distance between nipple seats, and is therefore about 3mm shorter
than the ERD as defined by Brandt. But it's a perfectly good spoke
length to just use without adding 3mm.

If you're like datakoll and like your spokes a bit shorter, you might be
tempted to subtract 3mm from a quoted ERD to get the spoke support
diameter and use that so your spokes come up to the bottom of the nipple
heads.

The problem is can you be sure it's really an ERD in the strict
Brandtian sense and not a spoke support diameter? Not everyone is so
careful with these terms. As far as many people are concerned, there is
just the length you want: it's just a number, and what you want to call
it ("ERD", "spoke support diameter", etc.) is mere technobabble. It
doesn't always occur to the man in the LBS to wonder whether sir would
like his spokes to run to the bottom or to the top of the nipples.

That's why if you find a number printed somewhere just go with that--
the worst that can happen is your spokes are a harmless 3mm from your
personal preference. But if you add 3mm or subtract 3mm thinking you
know what you're doing, but jump the wrong way, you could be 6mm out,
which could be a bit too far.

Quoted message said:

I've re-rimmed wheels with rims that were
5mm larger in published ERD than the originals without problems. Makes
me wonder how many nipple threads actually need to be engaged to build
a safe wheel.

I should think certainly not all of them.

Quoted message said:

I'm guessing from Jobst's response in my OP's thread that ERD is
precisely defined in "The Bicycle Wheel", but I've managed to build a
number of wheels without ever reading it.

He defines it as the length to get the spoke to the top of the nipple.

what he said.

datakoll said:

A Muzi said:

datakoll wrote:

-snip ERD redux-

Quoted message said:

urine-
As you can see, the approach to Rinard is incomplete. Addition of HOW
TO MEASURE articles obviously doesnot help overcome the problem JB-
Rinard et al brought on us: that ERD is spoke length when ERD is a
math constant for spoke length(s). An odd innocent twist to a semantic
pron]bl;em? Not with the intelligence carrying the obfuscation.

We calc and build wheels all day long and, believe me, we just cannot
afford to be wrong about a spoke length. Whatever frustration you have
would be shared _plus_ we'd lose the time of a wheel build. And time, as
you know, is money.

For a wheelbuilder doing several pairs per day of various road and track
wheels, a standard software tool such as "spocalc2" and a set of rim
measuring gauges[1] are all that's needed. Spoke length turns out, in
real life, to be a trivial and quick calculation.

For the dedicated home builder, I am sympathetic to the various
impediments to selecting a spoke length. Good failsafe methods include:
*Buying spokes when you buy the rims, making the vendor responsible
*Asking the spoke vendor to do a calculation for you
*Asking any of the many wheelbuilders who frequent here to calc for you.
*making a set of rim gauges, measuring your hubs and using spocalc2.

An alternate method is to nearly build with the wrong length spokes and
interpolate which, it seems, may work just fine for you now!

I hesitate to mention (but I will, here goes!) that various
wheelbuilders have distinct preferences as to whether the spoke ends at
the inside edge of the rim, at the outer end of the nipple or somewhere
in between. Functionally, across that 2mm range, it matters not; any are
just fine.

[1] two 350mm welding rods each with a 2mm washer brazed flush at the end.
--
Andrew Muziwww.yellowjersey.org
Open every day since 1 April, 1971

Andy Muzi perspective as LBS owner and my perspective as Group Two
amatuer wheel builder are disimilar. Muzi knows what he's doing and
the wheels are his repsonsibility but the wheels are not his wheels.
when wheels leave Yellow Jersey, the wheels are the responsibility of
the owner.
I don't know what I'm doing and the wheels are my wheels come hell or
high water.
There are more of me than there are of Muzi but Muzi is responsible
for more wheels-which is a good deal for the planet.
Andrew's solution to spoke length IS NOT ERD. Andy's photo for the
first run in over ERD clear;y showed a spoke short of the nipples slot
base-waaaaaaaay down the road from the nipple's head.

My deal here is snot selling wheels to the non wheel building publick.
My deal is spreading some education on ERD thru RBT after an expert
(which is another difference, I gotta deal with THE EXPERT and Muzi is
the expert) sent the Nth batch of incorrect spoke lengths then swore
up and down that Rinard and Godel vouched his lengths were the right
lengths.

yet again dude, post your rim and hub data so we can work it out for
you. if you don't want to do it yourself. relying on a shop to sell
you what they happen to have isn't always going to give you what you
actually want.

Quoted message said:

I recommended that Rinard change his evil ways avoiding further
inconvenience for the novice wheel builder before we get out there and
burnum out.

In article <[email hidden]>,

John Everett said:

Even though I've now ordered the spokes I was writing about when I
started the ERD thread, I still never received a clear answer to my
original question. Let me rephrase:

Should ERD actually be the diameter of the circle defined by the ends
of the spokes in the built wheel?

It is the diameter of the circle defined by the outermost
surface of the nipples. Many spoke calculators aim to get
the end of the spoke to or almost to that circle, even taking
into account the elastic elongation of the spoke.

Quoted message said:

If so, should the end of the spokes
theoretically be even with the top of the nipple, or buried somewhere
inside the nipple? If buried, should they be even with the outside
surface of the rim holes, or even with the bottom of the screwdriver
slot?

Note that we're talking about millimeter differences here, which
strikes me as a bit like discussing the number of angels the can dance
on the head of a pin. ;-)

Do not ignore small corrections. They can add up
and leave you with a situation that will take
you far longer to remedy than the initial time
investment in getting it right. People who know,
know what can be ignored because the have calculated
the error bounds far closer than one millimeter.

Quoted message said:

I've re-rimmed wheels with rims that were
5mm larger in published ERD than the originals without problems. Makes
me wonder how many nipple threads actually need to be engaged to build
a safe wheel.

Asking me? All of them.

Quoted message said:

I'm guessing from Jobst's response in my OP's thread that ERD is
precisely defined in "The Bicycle Wheel", but I've managed to build a
number of wheels without ever reading it.

Are you asking for our advice?

--
Michael Press

no itsnot what he said and frankly he can't add subtract do trig or
chew gum and walk.

A bicycle wheel is of two parts. Two cones mated at the base, aka RIM,
and connected at the points or apex (?) by an axle.

THERE IS NO DIAMETER on a bicycle wheel.
THERE IS NO ERD. ERD EXISTS ONLY IN SPOKE CALC SOFTWARE

THIS IS THE PROBLEM.

Its like the Sienfeld Conundrum: if you measure ERD it exists but when
you stop measuring ERD it does not exist,

OBVIOULSY.

you see Beam ? That's the ongoing controverys raised here not the
fact that the MO spokes were again the wrong lengths. people are
wandering the landscape muttering about ERD and getting incorrect
spoke lengths caws they are misled by spoke calcs into believing the
ERD is a spoke length when itsnot a spoke length. Damn thing doesn;t
exists for &^^6*FRT!!

In article <[email hidden]>,

A Muzi said:

For a wheelbuilder doing several pairs per day of various road and track
wheels, a standard software tool such as "spocalc2" and a set of rim
measuring gauges[1] are all that's needed.

[...]

Quoted message said:

[1] two 350mm welding rods each with a 2mm washer brazed flush at the end.

Neat.

--
Michael Press

Michael Press said:

In article <[email hidden]>,

John Everett said:

Even though I've now ordered the spokes I was writing about when I
started the ERD thread, I still never received a clear answer to my
original question. Let me rephrase:

Quoted message said:

Should ERD actually be the diameter of the circle defined by the ends
of the spokes in the built wheel?

It is the diameter of the circle defined by the outermost
surface of the nipples. Many spoke calculators aim to get
the end of the spoke to or almost to that circle, even taking
into account the elastic elongation of the spoke.

Quoted message said:

If so, should the end of the spokes
theoretically be even with the top of the nipple, or buried somewhere
inside the nipple? If buried, should they be even with the outside
surface of the rim holes, or even with the bottom of the screwdriver
slot?

Quoted message said:

Note that we're talking about millimeter differences here, which
strikes me as a bit like discussing the number of angels the can dance
on the head of a pin.  ;-)

Do not ignore small corrections. They can add up
and leave you with a situation that will take
you far longer to remedy than the initial time
investment in getting it right. People who know,
know what can be ignored because the have calculated
the error bounds far closer than one millimeter.

Quoted message said:

I've re-rimmed wheels with rims that were
5mm larger in published ERD than the originals without problems. Makes
me wonder how many nipple threads actually need to be engaged to build
a safe wheel.

Asking me? All of them.

Quoted message said:

I'm guessing from Jobst's response in my OP's thread that ERD is
precisely defined in "The Bicycle Wheel", but I've managed to build a
number of wheels without ever reading it.

Are you asking for our advice?

--
Michael Press

See here's another one.
YO MATH WHIZ ? if ERD is a diameter then why are rear spokes in two
lengths ?

datakoll said:

Michael Press said:

In article <[email hidden]>,
 John Everett <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Even though I've now ordered the spokes I was writing about when I
started the ERD thread, I still never received a clear answer to my
original question. Let me rephrase:

Quoted message said:

Quoted message said:

Should ERD actually be the diameter of the circle defined by the ends
of the spokes in the built wheel?

Quoted message said:

It is the diameter of the circle defined by the outermost
surface of the nipples. Many spoke calculators aim to get
the end of the spoke to or almost to that circle, even taking
into account the elastic elongation of the spoke.

Quoted message said:

Quoted message said:

If so, should the end of the spokes
theoretically be even with the top of the nipple, or buried somewhere
inside the nipple? If buried, should they be even with the outside
surface of the rim holes, or even with the bottom of the screwdriver
slot?

Quoted message said:

Quoted message said:

Note that we're talking about millimeter differences here, which
strikes me as a bit like discussing the number of angels the can dance
on the head of a pin.  ;-)

Quoted message said:

Do not ignore small corrections. They can add up
and leave you with a situation that will take
you far longer to remedy than the initial time
investment in getting it right. People who know,
know what can be ignored because the have calculated
the error bounds far closer than one millimeter.

Quoted message said:

Quoted message said:

I've re-rimmed wheels with rims that were
5mm larger in published ERD than the originals without problems. Makes
me wonder how many nipple threads actually need to be engaged to build
a safe wheel.

Quoted message said:

Asking me? All of them.

Quoted message said:

Quoted message said:

I'm guessing from Jobst's response in my OP's thread that ERD is
precisely defined in "The Bicycle Wheel", but I've managed to build a
number of wheels without ever reading it.

Quoted message said:

Are you asking for our advice?

Quoted message said:

--
Michael Press

See here's another one.
YO MATH WHIZ ? if ERD is a diameter then why are rear spokes in two
lengths ?- Hide quoted text -

- Show quoted text -

again... ERD is a math constant used to derive spoke lengths. ERD
exists as a measurment, a number not as a spoke length. NOT AS A SPOKE
LENGTH.

butbutbut for some inexplicable reason, Rinard and Brandt go on to
confuse c-o-n-f-u-s-e ERD with spoke length.

and promulgulate the confucion with extraordinary success from the
looks of it.

pawsibley other spoke calcs do the same, i dunno. By the time i get
thru one wheel I'm thru for the year but this time...I'm too busy. the
*&*((( with it.