Wheel Build Brain Tickler

Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

On Aug 21, 9:14*am, "D'ohBoy" wrote:
Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.

On Aug 21, 9:56*am, landotter wrote:
On Aug 21, 9:14*am, "D'ohBoy" wrote:





Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.

D'ohBoy

On Aug 21, 10:10*am, "D'ohBoy" wrote:
On Aug 21, 9:56*am, landotter wrote:



On Aug 21, 9:14*am, "D'ohBoy" wrote:

Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. *But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. *Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.

When you pluck a spoke you can also cause the rim to vibrate, you
might be hearing some differing harmonics.

On Fri, 21 Aug 2009 08:10:05 -0700 (PDT), D'ohBoy wrote:

On Aug 21, 9:56*am, landotter wrote:
On Aug 21, 9:14*am, "D'ohBoy" wrote:





Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.


f = ((t*g/pi*d)^-2)/l*r*2

where f=frequency, t = tension, g = gravity, pi = 3.14etcetera, d = wire
density, l = wire length, r = wire radius, and 2 = 2 (this last point for
bill sornson as he might have trouble with it otherwise).

D'ohBoy wrote:
On Aug 21, 9:56 am, landotter wrote:
On Aug 21, 9:14 am, "D'ohBoy" wrote:





Riddle me this:
My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. It also tells me that another rear wheel, same
spokes, is 105 kgf.
Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.
I am using identical technique with the TM-1 across the wheels.
How can this be?
I think I know but I was wondering if anyone else would come up with
the same answer.
D'ohBoy
Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. Bout 5 mm different.

I thought this page was one of the best-known arguments for the tone
method:http://www.bikexprt.com/bicycle/tension.htm

It lists different "goal" tones for different lenghts (but argues for
similar "goal" tones across different gauges.

Mark J.

On 21 Aug, 16:10, "D'ohBoy" wrote:
On Aug 21, 9:56*am, landotter wrote:



On Aug 21, 9:14*am, "D'ohBoy" wrote:

Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. *But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. *Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.

A stiffer rim may result in a higher reading, for it is displaced less
when the instrument is applied.

5mm will not make a significant audible change to anyone other than a
practising musician. Check that the spoke diameters are the same,
use a micrometer. If they are butted spokes, check that the butt
length is equal. An 'A' is high for 14swg an 'F' is better assuming
12" spokes. IIRC an A is about the limit for 16swg on a 27" wheel
because it makes it so much more susceptible to snapping with impact.
It is also the limit of tension for most light to middleweight rims,
buckling or splitting follow with highrer tensions.

Are the spokes really the same? Did they come from they same box?
Did they come off the same reel of wire? Have they been treated in
the same manner? Do they have equal temper?

You say they are different lengths so it is more likely than not they
are from a different reel of wire. The assumption that an intrument
can measure the tension of a spoke by bending it is false when the
temper of the wire and hence its inherent stiffness is not taken into
account by the instrument. Your observation has indeed highlighted
the problem of using a 'tension gauge' to assess spoke tension.
Temper of spokes varies between batches, different wire sources will
produce slightly different metals despite working to a specification.
The temper of the finished spoke will vary despite subsequent
processing in the spoke factory being consistent.

Using a spokes resonant frequency, or musical pitch to measure tension
is accurate for it does not displace the components being measured and
is not affected by temper variation.

On 21 Aug, 16:30, landotter wrote:
On Aug 21, 10:10*am, "D'ohBoy" wrote:



On Aug 21, 9:56*am, landotter wrote:

On Aug 21, 9:14*am, "D'ohBoy" wrote:

Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. *But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. *Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.

When you pluck a spoke you can also cause the rim to vibrate, you
might be hearing some differing harmonics.

The rim is much stiffer than a spoke. it is the other spokes which
are exited which are creating audible interference. They can be
silenced by threading double insulated mains (electric supply) flex
through them. Rope may also be suitable.

On Aug 21, 1:01*pm, someone wrote:
On 21 Aug, 16:30, landotter wrote:





On Aug 21, 10:10*am, "D'ohBoy" wrote:

On Aug 21, 9:56*am, landotter wrote:

On Aug 21, 9:14*am, "D'ohBoy" wrote:

Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. *But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. *Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.

When you pluck a spoke you can also cause the rim to vibrate, you
might be hearing some differing harmonics.

The rim is much stiffer than a spoke. *it is the other spokes which
are exited which are creating audible interference. *They can be
silenced by threading double insulated *mains (electric supply) flex
through them. * Rope may also be suitable.- Hide quoted text -

- Show quoted text -

Okay, I thought someone would ask about the rims, but the lower tone,
higher tension wheel, in addition to having shorter spokes, also is
based on a *carbon* rim, a material which, according to much marketing
lit, dampens high frequency vibration.

So my guess is that the higher frequencies are being damped by the
rim, hence, the tone is lower. All of this is based on marketing
though

D'ohBoy

On 21 Aug, 19:22, "D'ohBoy" wrote:
On Aug 21, 1:01*pm, someone wrote:



On 21 Aug, 16:30, landotter wrote:

On Aug 21, 10:10*am, "D'ohBoy" wrote:

On Aug 21, 9:56*am, landotter wrote:

On Aug 21, 9:14*am, "D'ohBoy" wrote:

Riddle me this:

My tensiometer (Park TM-1) tells me that one rear wheel is maxed (mfr
spec) at 130 kgf DS. *It also tells me that another rear wheel, same
spokes, is 105 kgf.

Yet I pluck the spokes on the (TM-1 reported) higher-tensioned wheel
and the tone is distinctly lower. *I am not musical so I cannot say
octaves, or simply a few notes, but merely distinctly.

I am using identical technique with the TM-1 across the wheels.

How can this be?

I think I know but I was wondering if anyone else would come up with
the same answer.

D'ohBoy

Larger gauge, unbutted, or shorter spoke than the soprano wheel.- Hide quoted text -

- Show quoted text -

Same spokes, but different lengths, you are correct. *But never has
anyone suggested that the tone method (shooting for an "A", IIRC)
varies based on spoke length. *Bout 5 mm different.

But I don't think that that 5 mm ("higher" tension is 5 mm shorter)
would create a significant tone difference, especially given the
supposed 25 kgf higher tension and significantly lower tone for the
shorter spoke.

When you pluck a spoke you can also cause the rim to vibrate, you
might be hearing some differing harmonics.

The rim is much stiffer than a spoke. *it is the other spokes which
are exited which are creating audible interference. *They can be
silenced by threading double insulated *mains (electric supply) flex
through them. * Rope may also be suitable.- Hide quoted text -

- Show quoted text -

Okay, I thought someone would ask about the rims, but the lower tone,
higher tension wheel, in addition to having shorter spokes, also is
based on a *carbon* rim, a material which, according to much marketing
lit, dampens high frequency vibration.

So my guess is that the higher frequencies are being damped by the
rim, hence, the tone is lower. *All of this is based on marketing
though

The vibrations pass through the hub even with the axle clamped up.
Try damping the other spokes when assessing pitch if you are unable to
rectify the difference. Strike the spokes with a fat marker pen at
their crossing point or neare the hub for a clear tone (with other
spokes damped with flex or rope).