What is ERD...really?

[DirtRoadie]

On Mar 9, 11:40 pm, [email protected] wrote:
> On Sun, 9 Mar 2008 21:32:06 -0700 (PDT), DirtRoadie
>
> <[email protected]> wrote:
> >You must have a measuring tool that I do not have. I cannot "measure"
> >ERD  on any rim ...

> Dear DR,
>
> I may be misunderstanding you,

Yes, I believe so. But it is largely a matter of semantics.

> but have a look at this page:
>  http://www.sheldonbrown.com/rinard/spocalc.htm#MeasureHubAndRim
>
> Page down once to the diagram of the double-walled rims, and it shows
> how to measure the ERD from the top of one spoke nipple inside a
> double-walled rim to the other.

No, it shows how to *calculate* ERD by taking some other measurements
AND doing some calculations - "ERD = A + 2B."
While it would be simple enough to design a tool to simply *measure*
ERD in one single step (perhaps Fogel Labs would like to take on this
project), I have no such tool and must rely on calculating ERD based
upon the formula shown. That was my point.

DR

 

[[email protected]]

The term "Effective Rim Diameter" ERD was introduced in "the Bicycle
Wheel" along with equations for calculating spoke length in the
section called "Equations". Those equations were subsequently used by
various people who have web sites that enable users to enter wheel
dimensions to arrive at spoke lengths. The definition is also given
in that section of the book. Those definitions have been distorted in
spite of the text that I believe is unambiguous.

Jobst Brandt

 

[datakoll]

divinity deleted. off course ERD is measurabbble in a rim. what is
this, CERN?
build the beam with dishing spacers, place hub into depression or axle
hole, rim on dish spoacers and measure with a stiff wire, mark with
tape.

in depth knowledge of why the MO spokes I receive are in incorrect
lengths comes from these here posts believe you me.

 

[Michael Press]

In article
<5d92b46d-eabc-4d41-bd53-6edf2dd2be97@p73g2000hsd.googlegroups.com>,
DirtRoadie <[email protected]> wrote:

> On Mar 9, 3:27 pm, Michael Press <[email protected]> wrote:
> > > ERD  is the diameter of the circle defined by the spoke ends and takes
> > > into account that a spoke must extend into the rim a bit.  It is
> > > slightly larger than the inner diameter of a rim. ERD is not actually
> > > "measured" - it is either an estimate or a calculation.  
> >
> > It is best measured. A URL for a method is posted in this thread.
> > It really is measured. Put nipples on a some spokes, measure
> > some distances on the spoke, put two spokes a pair of antipodal
> > points, measures some more, add and subtract some measurements.
> > Do it for three pair of diameters on the rim. If your three
> > measurements do not rectify, draw a picture, think through
> > the method, and measure some more.
>
> You must have a measuring tool that I do not have. I cannot "measure"
> ERD on any rim (all being double walled) that I have worked with in
> the recent past since the top surface of the nipple heads has always
> been recessed below the bed of the rim. That's why I
> "calculate" (from some measurements I CAN make) as I described (and
> even you describe adding and subtracting some measurements) or
> "estimate" it as I also described since many calcualtion have shown
> actual rim inner diameter +10 mm to be a usable estimate for
> ERD.

We seem to agree. Measure, then calculate.
The calculation is rather less of a factor
than a measurement and calculation based on theory
such as the yield strength of a quick release skewer
from its dimensions and composition.

--
Michael Press

 

[DirtRoadie]

On Mar 10, 3:54 pm, [email protected] wrote:
> The term "Effective Rim Diameter" ERD was introduced in "the Bicycle
> Wheel" along with equations for calculating spoke length in the
> section called "Equations".  Those equations were subsequently used by
> various people who have web sites that enable users to enter wheel
> dimensions to arrive at spoke lengths.  The definition is also given
> in that section of the book.  Those definitions have been distorted in
> spite of the text that I believe is unambiguous.
>
> Jobst Brandt

Jobst -
I won't dispute your introduction of the term "ERD" although I have
never liked the concept since it relies on assumptions regarding
nipple measurements that may or may not be true. But as to the easily
derived equations, gim'me a break. I suppose that (along with the
wheel itself) you invented the underlying trigonometry too?

DR

 

[datakoll]

DR,

Discussion or ERD crossed the threshold of cycle mechanics into the
realm of Glabl Warming. Given a simple concept meant to simplify a
simple measure and build operation, participants wandered off into a
quagmire of illusion, ill defined concepts, misunderstandings, sheer
mind numbing blockheadedness and stupidity.

Your comment is no different: "relies on assumptions regarding
nipple measurements that may or may not be true."

Unbelievable. You cannot read a soup can label ?

 

[Tom Sherman]

DirtRoadie who? wrote:
> On Mar 10, 3:54 pm, [email protected] wrote:
>> The term "Effective Rim Diameter" ERD was introduced in "the Bicycle
>> Wheel" along with equations for calculating spoke length in the
>> section called "Equations". Those equations were subsequently used by
>> various people who have web sites that enable users to enter wheel
>> dimensions to arrive at spoke lengths. The definition is also given
>> in that section of the book. Those definitions have been distorted in
>> spite of the text that I believe is unambiguous.
>>
>> Jobst Brandt
>
> Jobst -
> I won't dispute your introduction of the term "ERD" although I have
> never liked the concept since it relies on assumptions regarding
> nipple measurements that may or may not be true. But as to the easily
> derived equations, gim'me a break. I suppose that (along with the
> wheel itself) you invented the underlying trigonometry too?
>
Sheeesh! Everyone knows that Jobst Brandt invented the spoked bicycle
wheel. Before Jobst, all wheels were hand carved from granite.

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

 

[datakoll]

On Mar 10, 5:54 pm, [email protected] wrote:
> The term "Effective Rim Diameter" ERD was introduced in "the Bicycle
> Wheel" along with equations for calculating spoke length in the
> section called "Equations".  Those equations were subsequently used by
> various people who have web sites that enable users to enter wheel
> dimensions to arrive at spoke lengths.  The definition is also given
> in that section of the book.  Those definitions have been distorted in
> spite of the text that I believe is unambiguous.
>
> Jobst Brandt

A carefully crafted and crafty paragraph this, a revision exonerating
Brandt's egotistical criminal act of misdefinition.
"Subsequently used" - various demons wrenched poor Brandt's concept
from it's bed. raping it on the altar of self serving websites.
Yet while permanently defiled by the unworthy, the Brandt ERD concept
carried on in pristine mathematicall glory and insight "enabling
users." to follow the path lit by Brandt's brilliant trigonometry
"to arrive at" the holy city: UPSville, Returnlabel.

Having shed his guilt to others, Brandt then restates his guilt.
Incroyable !

The witless "users" arrived at "spoke lengths."

EAT BEFORE JULY 2014. USE AS DIRECTED. ASSEMBLE IN REVERSE ORDER.

SPOKE LENGTHS? Jobst, what kind of SPOKE LENGTHS?

ERD spoke lengths or spoke lengths that build the wheel AESL spoke
lengths?

Sacre Blue.

 

[jim beam]

datakoll wrote:
> On Mar 10, 5:54�pm, [email protected] wrote:
>> The term "Effective Rim Diameter" ERD was introduced in "the Bicycle
>> Wheel" along with equations for calculating spoke length in the
>> section called "Equations". �Those equations were subsequently used by
>> various people who have web sites that enable users to enter wheel
>> dimensions to arrive at spoke lengths. �The definition is also given
>> in that section of the book. �Those definitions have been distorted in
>> spite of the text that I believe is unambiguous.
>>
>> Jobst Brandt
>
> A carefully crafted and crafty paragraph this,

no ****. to spell it out, "introduction" carefully /implies/ invention
while walking the fine line of truthfulness by not quite /actually/
doing so.


> a revision exonerating
> Brandt's egotistical criminal act of misdefinition.
> "Subsequently used" - various demons wrenched poor Brandt's concept
> from it's bed. raping it on the altar of self serving websites.
> Yet while permanently defiled by the unworthy, the Brandt ERD concept
> carried on in pristine mathematicall glory and insight "enabling
> users." to follow the path lit by Brandt's brilliant trigonometry
> "to arrive at" the holy city: UPSville, Returnlabel.
>
> Having shed his guilt to others, Brandt then restates his guilt.
> Incroyable !

indeed. but baron münchhausen is never short on ability to entertain -
you have to give him that.


>
> The witless "users" arrived at "spoke lengths."
>
> EAT BEFORE JULY 2014. USE AS DIRECTED. ASSEMBLE IN REVERSE ORDER.
>
> SPOKE LENGTHS? Jobst, what kind of SPOKE LENGTHS?
>
> ERD spoke lengths or spoke lengths that build the wheel AESL spoke
> lengths?
>
> Sacre Blue.
>