Spoke Length: Measurement Methology And Criticality?

[(PeteCresswell)]

Anybody know the right way to measure spoke length?

Once the drum brake hub I ordered arrives, my plan is to measure
the spoke-hole-center-to-axle-center distance on the old and new
hubs; pull a spoke from the rim that I'm going to replace the hub
on; measure it; and order new spokes that are shorter by the
diff.

But that depends on my measuring the old spoke properly.

Seems like there's a few mm of wiggle room there depending on
exactly how it's measured.

Or am I over-thinking this and there's X mm of slop that can be
taken up by the nipples?
--
PeteCresswell

 

[datakoll]

NOT HERE FOR ERD? search RBT for: ERD

see Andrew Muzi's photo

suggestions: buy a steel rule in MM and a cheap vernier caliper AND a
spoke ruler from Nashbar or ? Nashbar's ruler isnot long enough so
tape the pocket rule to it and both to the counter top with magic
tape.
search for example: http://www.geocities.com/spokeanwheel/measure.htm

place hub under counter top then use counter edge for one side rule
measure stop point.

the ERD in Rinard is from the top of the nipple head. Practically,
spokes do not go to nipple head's top surface. see Muzi's photo.

familiarize with the threading on spoke and nipple. use magic tape and
your new steel pocket rule. draw diagram of where threads are in
relation to spoke length from hub hole to inside rim surface.

16mm DT nipples and DT spokes do not thread up to the nipples slot
base. check your nipple-spoke threading relationship.

Software at a Trek LBS was unable to develop lengths for double wall
rims, eg Sun Cr-18 and Rhyno.

See ERD post for Carl Fogel's English spoke calc. There's a graphic
calc there to try.

use a dishing beam of correct length straight lumber pref hardwood
from skid. drill hub hole with spade bit to rest hub end in. block up/
shim diameter lengths for front wheel bottom hub hole to center hub
then for rear hub dishing gear side. shims are interchanghable off
course with thin bolt thru beam.Possible to get fancy and use large
diameter washer and substitue axle runningthru beam but totally
unnnnnecessary. take the quick release out and wing it into the spade
depression.

assemble wheel on beam using sheldon brown's instructions. with the
beam, possible to get a quick real time tape measure with only 8-12-16
spokes from LBS for checking the Rinard measure.

Rinard works good, but itsnot the correct length. DEDUCT FROM RINARD
ERD from your graphic threading diagram/measurements of the spoke/
nipple/rim your building as in Anrdrw Muzi's photo.
That is to say the spoke end should fall short of the nipple slot base-
your choice as to where.

I go short. With a touring load the rig wears out: short spokes grow
longer, long spokes get too long and expletive deleted.

EEEYYYAHAHAHHAHEYEYHAHAH **&&^&^##@!11

 

[landotter]

On Feb 21, 8:38 pm, "(PeteCresswell)" <[email protected]> wrote:
> Anybody know the right way to measure spoke length?
>
> Once the drum brake hub I ordered arrives, my plan is to measure
> the spoke-hole-center-to-axle-center distance on the old and new
> hubs; pull a spoke from the rim that I'm going to replace the hub
> on; measure it; and order new spokes that are shorter by the
> diff.
>
> But that depends on my measuring the old spoke properly.
>
> Seems like there's a few mm of wiggle room there depending on
> exactly how it's measured.
>
> Or am I over-thinking this and there's X mm of slop that can be
> taken up by the nipples?

Couple mms at most, double wall rims have given us this luxury. Why
not just use Spocalc? Easy enough to get the hub and rim specs, then
plug them in and let technology work for ya.

http://www.damonrinard.com/spocalc.htm

 

[datakoll]

and use a bright light. Home Depot and Wal sell an aluminum half
sphere with clamp. buy one. donot work in the dark.

 

[datakoll]

On Feb 21, 10:51 pm, landotter <[email protected]> wrote:
> On Feb 21, 8:38 pm, "(PeteCresswell)" <[email protected]> wrote:
>
> > Anybody know the right way to measure spoke length?
>
> > Once the drum brake hub I ordered arrives, my plan is to measure
> > the spoke-hole-center-to-axle-center distance on the old and new
> > hubs; pull a spoke from the rim that I'm going to replace the hub
> > on; measure it; and order new spokes that are shorter by the
> > diff.
>
> > But that depends on my measuring the old spoke properly.
>
> > Seems like there's a few mm of wiggle room there depending on
> > exactly how it's measured.
>
> > Or am I over-thinking this and there's X mm of slop that can be
> > taken up by the nipples?
>
> Couple mms at most, double wall rims have given us this luxury. Why
> not just use Spocalc? Easy enough to get the hub and rim specs, then
> plug them in and let technology work for ya.
>
> http://www.damonrinard.com/spocalc.htm

i will restrain myself. i will restrain myself. i wil....

 

[jim beam]

(PeteCresswell) wrote:
> Anybody know the right way to measure spoke length?
>
> Once the drum brake hub I ordered arrives, my plan is to measure
> the spoke-hole-center-to-axle-center distance on the old and new
> hubs; pull a spoke from the rim that I'm going to replace the hub
> on; measure it; and order new spokes that are shorter by the
> diff.

that only works for radial spokes, and you're not well advised to use
those on a hub braked wheel.


>
> But that depends on my measuring the old spoke properly.
>
> Seems like there's a few mm of wiggle room there depending on
> exactly how it's measured.
>
> Or am I over-thinking this and there's X mm of slop that can be
> taken up by the nipples?

the hub info is bound to be out there somewhere. simply input relevant
hub [and rim] dimensions to rinard's spokecalc and calculate. if you're
lucky and act promptly, maybe both will arrive at the same time.

one last thing: it's much harder to build a wheel using an old rim vs. a
new one - buying a new one while you're ordering your spokes will make
life simpler.

 

[(PeteCresswell)]

Per datakoll:
> http://www.geocities.com/spokeanwheel/measure.htm

"Spokes are measured from the edge of the bend closest to the
threaded end of the spoke, not from the center of the head like
one might assume."

Suspicion confirmed.... Thanks, I'll keep reading.
--
PeteCresswell

 

[datakoll]

On Feb 21, 9:38 pm, "(PeteCresswell)" <[email protected]> wrote:
> Anybody know the right way to measure spoke length?
>
> Once the drum brake hub I ordered arrives, my plan is to measure
> the spoke-hole-center-to-axle-center distance on the old and new
> hubs; pull a spoke from the rim that I'm going to replace the hub
> on; measure it; and order new spokes that are shorter by the
> diff.
>
> But that depends on my measuring the old spoke properly.
>
> Seems like there's a few mm of wiggle room there depending on
> exactly how it's measured.
>
> Or am I over-thinking this and there's X mm of slop that can be
> taken up by the nipples?
> --
> PeteCresswell

ahhh? the trig from one triangle minus the trig from another? ?????

use the beam and 8 or 12 spoke at equal spacings-4 or 6 one side then
ditto. the complete solution to spoke calc is real time measurement.

measure old spokes v, new spokes? slop? more than enough slop. gotta
spoke rule taped to the countertop with the spoke bend hole over the
side so's the spoke head goes thru? OK, learning how to measure from
this position only gives 2+ mm differences -/+. that is the measurer,
you, needs to learn a method for stabilizing measuring at that point-
with new spokes only. Press down at the bend and pull and press down
at the other end.
Now stabilize with used v. new spokes...probabbbbly enough -/+ mm to
reduce effectiveness for finding a good length.
build a beam, tape measure or stick measure then tape measure stick
(1X2"??), buy 8 trial spokes and urine the correct direction Rinard or
not.

 

[Ozark Bicycle]

On Feb 21, 9:55 pm, datakoll <[email protected]> wrote:
> On Feb 21, 10:51 pm, landotter <[email protected]> wrote:
>
>
>
> > On Feb 21, 8:38 pm, "(PeteCresswell)" <[email protected]> wrote:
>
> > > Anybody know the right way to measure spoke length?
>
> > > Once the drum brake hub I ordered arrives, my plan is to measure
> > > the spoke-hole-center-to-axle-center distance on the old and new
> > > hubs; pull a spoke from the rim that I'm going to replace the hub
> > > on; measure it; and order new spokes that are shorter by the
> > > diff.
>
> > > But that depends on my measuring the old spoke properly.
>
> > > Seems like there's a few mm of wiggle room there depending on
> > > exactly how it's measured.
>
> > > Or am I over-thinking this and there's X mm of slop that can be
> > > taken up by the nipples?
>
> > Couple mms at most, double wall rims have given us this luxury. Why
> > not just use Spocalc? Easy enough to get the hub and rim specs, then
> > plug them in and let technology work for ya.
>
> >http://www.damonrinard.com/spocalc.htm
>
> i will restrain myself. i will restrain myself. i wil....

Better to retrain yourself. Spocalc works perfectly well.

 

[datakoll]

On Feb 22, 10:05 am, datakoll <[email protected]> wrote:
> On Feb 21, 9:38 pm, "(PeteCresswell)" <[email protected]> wrote:
>
>
>
>
>
> > Anybody know the right way to measure spoke length?
>
> > Once the drum brake hub I ordered arrives, my plan is to measure
> > the spoke-hole-center-to-axle-center distance on the old and new
> > hubs; pull a spoke from the rim that I'm going to replace the hub
> > on; measure it; and order new spokes that are shorter by the
> > diff.
>
> > But that depends on my measuring the old spoke properly.
>
> > Seems like there's a few mm of wiggle room there depending on
> > exactly how it's measured.
>
> > Or am I over-thinking this and there's X mm of slop that can be
> > taken up by the nipples?
> > --
> > PeteCresswell
>
> ahhh? the trig from one triangle minus the trig from another? ?????
>
> use the beam and 8 or 12 spoke at equal spacings-4 or 6 one side then
> ditto. the complete solution to spoke calc is real time measurement.
>
> measure old spokes v, new spokes? slop? more than enough slop. gotta
> spoke rule taped to the countertop with the spoke bend hole over the
> side so's the spoke head goes thru? OK, learning how to measure from
> this position only gives 2+ mm differences -/+. that is the measurer,
> you, needs to learn a method for stabilizing measuring at that point-
> with new spokes only. Press down at the bend and pull and press down
> at the other end.
> Now stabilize with used v. new spokes...probabbbbly enough -/+ mm to
> reduce effectiveness for finding a good length.
> build a beam, tape measure or stick measure then tape measure stick
> (1X2"??), buy 8 trial spokes and urine the correct direction Rinard or
> not.- Hide quoted text -
>
> - Show quoted text -

before using your method or Rinard
build an altar with a white floor, sacrifice an animal . get a big
animal. larger the better. cut the animals throat at the carotid or
juglar. more blood the better. see alt.sacrifice for nuance. sell
tickets.

 

[[email protected]]

(PeteCresswell) skrev:

> Once the drum brake hub I ordered arrives, my plan is to measure
> the spoke-hole-center-to-axle-center distance on the old and new
> hubs; pull a spoke from the rim that I'm going to replace the hub
> on; measure it; and order new spokes that are shorter by the
> diff.
>
> But that depends on my measuring the old spoke properly.
>
> Seems like there's a few mm of wiggle room there depending on
> exactly how it's measured.

You measure spoke length from the inside of the spoke elbow from where
the elbow starts to curve upwards.
The sources I know of (Roger Musson http://www.wheelpro.co.uk/wheelbuilding/book.php)
says that spokes elongate by 0,5 mm when tensioned. Not sure whether
this is a permanent elongation. Anyway if the two hubs are identical
just measure a spoke and buy a spoke the same size or 1 mm shorter if
possible. +-1 mm shouldn't be a problem at all. You are better of with
spokes that are somewhat too short so that some thread is visible,
than spokes that are too long, since that means that the necessary
tension may not be achieved.
Just to be sure, check the old wheel for whether any thread is visible
near the spoke nipples (spokes on the short side) or if the spokes
protrude upwards inside the spoke nipple (spokes on the long side).

--
Regards

 

[datakoll]

On Feb 22, 11:37 am, [email protected] wrote:
> (PeteCresswell) skrev:
>
> > Once the drum brake hub I ordered arrives, my plan is to measure
> > the spoke-hole-center-to-axle-center distance on the old and new
> > hubs; pull a spoke from the rim that I'm going to replace the hub
> > on; measure it; and order new spokes that are shorter by the
> > diff.
>
> > But that depends on my measuring the old spoke properly.
>
> > Seems like there's a few mm of wiggle room there depending on
> > exactly how it's measured.
>
> You measure spoke length from the inside of the spoke elbow from where
> the elbow starts to curve upwards.
> The sources I know of (Roger Mussonhttp://www.wheelpro.co.uk/wheelbuilding/book.php)
> says that spokes elongate by 0,5 mm when tensioned. Not sure whether
> this is a permanent elongation. Anyway if the two hubs are identical
> just measure a spoke  and buy a spoke the same size or 1 mm shorter if
> possible. +-1 mm shouldn't be a problem at all. You are better of with
> spokes that are somewhat too short so that some thread is visible,
> than spokes that are too long, since that means that the necessary
> tension may not be achieved.
> Just to be sure, check the old wheel for whether any thread is visible
> near the spoke nipples (spokes on the short side) or if the spokes
> protrude upwards inside the spoke nipple (spokes on the long side).
>
> --
> Regards

they said: " just to be sure, sacrifice a horned animal"

 

[[email protected]]

On 22 Feb., 17:37, [email protected] wrote:

[snip]
I just realized that you were talking about a new and different hub.
If the hub isn't in the spocalc db, or in DT Swiss online spoke
calculator;
http://www.dtswiss.com/SpokesCalc/Welcome.aspx?language=en
then you have to measure it yourself. It is quite easy, here are the
instructions and a nice sheet to print out:

http://www.wheelpro.co.uk/spokecalc/
http://www.wheelpro.co.uk/spokecalc/hubmeasure.pdf

You can then use the data to calculate the correct spoke length, using
either spocalc or Mussons or DT Swiss' online calculators.
Always round downwards. If spocalc says 289,8 mm, round it down to 289
mm.
Always prefer slightly shorter spokes eg. Some if not all spoke
manufactures tend to have 1 mm jumps between their spokes, so if
spocalc says 288,6 mm spokes, but you can only get 289 mm or 287 mm
spokes, then get the shorter 287 mm spokes.

Musson's spoke calculator subtracts 0,5 mm from its results because of
spoke elongation:
http://www.wheelpro.co.uk/spokecalc/

I think spocalc gives "raw" values without any correction.

DT Swiss seems to have some kind of correction, but it doesn't says
how much or why.

--
Regards

 

[John Everett]

On Thu, 21 Feb 2008 21:38:28 -0500, "(PeteCresswell)" <[email protected]>
wrote:

>Anybody know the right way to measure spoke length?
>

Spoke length is measured from the inside of the bend at the hub end to
the other end.

Pushing the macro capability of my camera I took a picture of the
modification I made to a plastic metric ruler in order to measure
spokes. It's at:

http://www.flickr.com/photos/sierrajohn/2284349192/

Looking closely I can now see I probably came up about a half
millimeter short when I cut the slot.


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

 

[(PeteCresswell)]

Per [email protected]:
>Anyway if the two hubs are identical
>just measure a spoke and buy a spoke the same size or 1 mm shorter if
>possible. +-1 mm shouldn't be a problem at all. You are better of with
>spokes that are somewhat too short

I'm kind of boggled by the measurements required for doing it the
right way. Seems like too much chance of error.

SpoCalc seems to come up with different lengths for rite/left
even though the dimensions are entered as being the same. OTOH,
the sheet doesn't document it's terminology and I'm kind of
guessing at the meaning of "OSB Offset spoke bed" - and the
number it comes up with is heavy by at least 15-18 mm...

So I guess it's pretty obvious that I'm making some significant
error.

The hubs are not the same diameter and, as somebody pointed out,
a straight diff in length based on hub diameter diff only works
for radial lacing.

OTOH, when I draw a right triangle with the old spoke on one side
at a length of 270mm, a short side length (the hub radius diff)
of 23.5mm and play with the numbers, it seems like that radius
diff is only good for one or 2 mm.

So I'm back to thinking I'll take the length of an old spoke,
subtract the hub spoke hole radius diff, and then knock off
another 1.5 mm for the diameter diff.
--
PeteCresswell

 

[jim beam]

(PeteCresswell) wrote:
> Per [email protected]:
>> Anyway if the two hubs are identical
>> just measure a spoke and buy a spoke the same size or 1 mm shorter if
>> possible. +-1 mm shouldn't be a problem at all. You are better of with
>> spokes that are somewhat too short
>
> I'm kind of boggled by the measurements required for doing it the
> right way. Seems like too much chance of error.
>
> SpoCalc seems to come up with different lengths for rite/left
> even though the dimensions are entered as being the same. OTOH,
> the sheet doesn't document it's terminology and I'm kind of
> guessing at the meaning of "OSB Offset spoke bed" - and the
> number it comes up with is heavy by at least 15-18 mm...
>
> So I guess it's pretty obvious that I'm making some significant
> error.
>
> The hubs are not the same diameter and, as somebody pointed out,
> a straight diff in length based on hub diameter diff only works
> for radial lacing.
>
> OTOH, when I draw a right triangle with the old spoke on one side
> at a length of 270mm, a short side length (the hub radius diff)
> of 23.5mm and play with the numbers, it seems like that radius
> diff is only good for one or 2 mm.
>
> So I'm back to thinking I'll take the length of an old spoke,
> subtract the hub spoke hole radius diff, and then knock off
> another 1.5 mm for the diameter diff.

but the spokes are not radial - there is more trig involved than that...

 

[A Muzi]

>> "(PeteCresswell)" <[email protected]> wrote:
>>> Anybody know the right way to measure spoke length?
>>> Once the drum brake hub I ordered arrives, my plan is to measure
>>> the spoke-hole-center-to-axle-center distance on the old and new
>>> hubs; pull a spoke from the rim that I'm going to replace the hub
>>> on; measure it; and order new spokes that are shorter by the
>>> diff.
>>> But that depends on my measuring the old spoke properly.
>>> Seems like there's a few mm of wiggle room there depending on
>>> exactly how it's measured.
>>> Or am I over-thinking this and there's X mm of slop that can be
>>> taken up by the nipples?

> datakoll <[email protected]> wrote:
>> ahhh? the trig from one triangle minus the trig from another? ?????
>> use the beam and 8 or 12 spoke at equal spacings-4 or 6 one side then
>> ditto. the complete solution to spoke calc is real time measurement.
>> measure old spokes v, new spokes? slop? more than enough slop. gotta
>> spoke rule taped to the countertop with the spoke bend hole over the
>> side so's the spoke head goes thru? OK, learning how to measure from
>> this position only gives 2+ mm differences -/+. that is the measurer,
>> you, needs to learn a method for stabilizing measuring at that point-
>> with new spokes only. Press down at the bend and pull and press down
>> at the other end.
>> Now stabilize with used v. new spokes...probabbbbly enough -/+ mm to
>> reduce effectiveness for finding a good length.
>> build a beam, tape measure or stick measure then tape measure stick
>> (1X2"??), buy 8 trial spokes and urine the correct direction Rinard or
>> not.

datakoll wrote:
> before using your method or Rinard
> build an altar with a white floor, sacrifice an animal . get a big
> animal. larger the better. cut the animals throat at the carotid or
> juglar. more blood the better. see alt.sacrifice for nuance. sell
> tickets.

Yeah, we knew that already:
http://groups.google.com/group/rec....3abc?lnk=gst&q=chicken+blood#c03cf91b468b3abc

27 Sep 2002, quite possibly the best r.b.t. post of all time

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

 

[Michael Press]

In article
<[email protected]>,
[email protected] wrote:

> (PeteCresswell) skrev:
>
> > Once the drum brake hub I ordered arrives, my plan is to measure
> > the spoke-hole-center-to-axle-center distance on the old and new
> > hubs; pull a spoke from the rim that I'm going to replace the hub
> > on; measure it; and order new spokes that are shorter by the
> > diff.
> >
> > But that depends on my measuring the old spoke properly.
> >
> > Seems like there's a few mm of wiggle room there depending on
> > exactly how it's measured.
>
> You measure spoke length from the inside of the spoke elbow from where
> the elbow starts to curve upwards.
> The sources I know of (Roger Musson http://www.wheelpro.co.uk/wheelbuilding/book.php)
> says that spokes elongate by 0,5 mm when tensioned. Not sure whether
> this is a permanent elongation.

If it were permanent, what restrains it from further elongation?

--
Michael Press

 

[Clive George]

"(PeteCresswell)" <[email protected]> wrote in message
news:[email protected]...
> Per [email protected]:
>>Anyway if the two hubs are identical
>>just measure a spoke and buy a spoke the same size or 1 mm shorter if
>>possible. +-1 mm shouldn't be a problem at all. You are better of with
>>spokes that are somewhat too short
>
> I'm kind of boggled by the measurements required for doing it the
> right way. Seems like too much chance of error.
>
> SpoCalc seems to come up with different lengths for rite/left
> even though the dimensions are entered as being the same. OTOH,
> the sheet doesn't document it's terminology and I'm kind of
> guessing at the meaning of "OSB Offset spoke bed" - and the
> number it comes up with is heavy by at least 15-18 mm...
>
> So I guess it's pretty obvious that I'm making some significant
> error.

Mmm, sounds quite likely.

So: what hub, what rim?

Are they in the database?

If not, what are their dimensions? Need distance between centre and flange
for both sides (would be the same for a normal front hub), diameter of
flange. Number of spokes, how many cross you want to do. And ERD of rim. Is
the rim symmetric or offset?

cheers,
clive

 

[A Muzi]

> Per [email protected]:
>> Anyway if the two hubs are identical
>> just measure a spoke and buy a spoke the same size or 1 mm shorter if
>> possible. +-1 mm shouldn't be a problem at all. You are better of with
>> spokes that are somewhat too short

(PeteCresswell) wrote:
> I'm kind of boggled by the measurements required for doing it the
> right way. Seems like too much chance of error.
>
> SpoCalc seems to come up with different lengths for rite/left
> even though the dimensions are entered as being the same. OTOH,
> the sheet doesn't document it's terminology and I'm kind of
> guessing at the meaning of "OSB Offset spoke bed" - and the
> number it comes up with is heavy by at least 15-18 mm...
>
> So I guess it's pretty obvious that I'm making some significant
> error.
>
> The hubs are not the same diameter and, as somebody pointed out,
> a straight diff in length based on hub diameter diff only works
> for radial lacing.
>
> OTOH, when I draw a right triangle with the old spoke on one side
> at a length of 270mm, a short side length (the hub radius diff)
> of 23.5mm and play with the numbers, it seems like that radius
> diff is only good for one or 2 mm.
>
> So I'm back to thinking I'll take the length of an old spoke,
> subtract the hub spoke hole radius diff, and then knock off
> another 1.5 mm for the diameter diff.

You could just look over at the tattoo of the guy standing next to you:
http://www.yellowjersey.org/photosfromthepast/SPOKFORM.JPG
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971