spoke gauge/spoke tension relation....

Quoted message said:

assuming the same hub and rim combination....how much higher would the
spoke tension be if you changed from a 3X with 1.8/2.0mm spokes to
1.5/2.0mm spokes?

The tension should be the same assuming everything is the same except the
spoke gauge.

Quoted message said:

on an unrealted note, i recently built another wheels set for a road
bike. the spokes when laced and tensioned, ended up to be about 2mm
too short. if you can imagine the slot in the nipple, for the nipple
driver, the spoke end is about 2mm below this point. i know that only
a portion of the nipple is actually threaded. will this be a problem
at some point?

Ideally, the spoke should come to the top of the slot so that you could not
place a screwdriver in the slot. Second best is if the spoke reaches the
bottom of the slot. What you've got is not ideal, but shouldn't be a
problem. I assume you can't see any exposed threads below the nipple.

Art Harris

On 5 Jan 2005 14:51:00 -0800, [email hidden]

Quoted message said:

assuming the same hub and rim combination....how much higher would the
spoke tension be if you changed from a 3X with 1.8/2.0mm spokes to
1.5/2.0mm spokes?

on an unrealted note, i recently built another wheels set for a road
bike. the spokes when laced and tensioned, ended up to be about 2mm
too short. if you can imagine the slot in the nipple, for the nipple
driver, the spoke end is about 2mm below this point. i know that only
a portion of the nipple is actually threaded. will this be a problem
at some point?

thanks in advance.

Dear TC,

Maybe I'm missing something, but wouldn't the right spoke
tension (whatever it is) remain the same as long as you had
the same number of spokes in the same cross-three pattern?

That is, the hub and the rim don't care how thick a spoke's
ankles are--they just notice how hard it pulls. To them, a
hundred pounds of tension is a hundred pounds of tension,
whether it's exerted through a motorcycle spoke, a butted 14
gauge DT spoke, or a kevlar string.

The reason for butted spokes is that, given the same
tension, a butted spoke is still strong enough, but more
elastic than a straight spoke. Its thinner mid-section
stretches farther and can therefore contract more as it
passes under the hub, so it doesn't lose all tension as soon
as a straight spoke (a bad thing that involves banging and
rattling). The thick butted ends are intended to leave more
metal at the ends, where fatigue breaks spokes.

As for spokes being 2mm short, that's just cosmetic. The
load is carried by the first few threads where the spoke
enters the nipple, not the whole length of the engagement.

Think of the nipple as a nut and the spoke as a bolt, and
you'll see that the threaded portion of the nipple is much
longer than it needs to be just to hold things together. The
threaded part of the nipple is longer than it needs to
be--the extra length is not for greater strength, but for
easier initial assembly and then for adjusting tension,
which will stretch the spokes slightly.

Carl Fogel

nope...no exposed threads below the nipple. thanks to you both. i
just want to be sure.
as for the spoke tension changes....got it. tensions is tension.

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

assuming the same hub and rim combination....how much higher would the
spoke tension be if you changed from a 3X with 1.8/2.0mm spokes to
1.5/2.0mm spokes?

Should be the same. The rim is what determines how high a tension you
can get. The strongest wheel is the one with the highest spoke tension.
So you always want to get the tension as high as the rim will allow.

-------------
Alex

The tension of the spoke needs to be the same, regardless of the gauge. A wheel is a pretensioned structure who's strength depends on the initial stress state. Because a butted spoke must be elastically deformed to a greater extent to achieve the same tension, the wheel constructed with butted spokes will have greater durability because rim deformations will result in less spoke tension loss. Racing engines utilize the same technique when bolt towers are used on the head bolts since increasing the length of a fastener is analogous to decreasing the diameter with respect to elasticity.

You need at least 6 turns of engagement on the nipple IF it is brass. Aluminum nipples NEED to be at the bottom of the slot MINIMUM, otherwise the nipples will fail.

Quoted message said:

You need at least 6 turns of engagement on the nipple IF it is brass.

Quoted message said:

Aluminum nipples NEED to be at the bottom of the trash can.

6!

dancedancedance. i'll go with it.

on first threads carrying loads-this would seem to be a faith based
concept not a manufacturing reality.

ahaso! on tension, on donner, on galileo-the spokes will twang at a
different pitch, will different twangs produce a different tensions
using the tensionometers?

Quoted message said:

assuming the same hub and rim combination....how much higher would the
spoke tension be if you changed from a 3X with 1.8/2.0mm spokes to
1.5/2.0mm spokes?

As was said, tension is tension. Most tensiometers use a measurement of
spoke deflection (bending) when held at two points and pressure is put on a
third between them to represent tension. Since different gauges of spokes
deflect differently under the same tension, the tensiometer readings are
'calibrated' to compensate for this. The numerical reading off the
tensiometer would be less for the 1.5 mm spoke than the 1.8 mm spoke given
the same tension.

Mike

Michael Dart said:

Quoted message said:

assuming the same hub and rim combination....how much higher would
the spoke tension be if you changed from a 3X with 1.8/2.0mm spokes
to 1.5/2.0mm spokes?

Quoted message said:

As was said, tension is tension. Most tensiometers use a
measurement of spoke deflection (bending) when held at two points
and pressure is put on a third between them to represent tension.
Since different gauges of spokes deflect differently under the same
tension, the tensiometer readings are 'calibrated' to compensate for
this. The numerical reading off the tensiometer would be less for
the 1.5 mm spoke than the 1.8 mm spoke given the same tension.

That's the case with currently available tensiometers but the one I
use does not measure across the spoke but rather on one side so
thickness doesn't enter into it and deflections over a four inch span
are nearly identical for 1.6 to 2.0mm diameter spokes. Although the
instrument is shown in "the Bicycle Wheel", manufacturers of these
instruments do not recognize the advantage of unilateral measurement
and require the user to use a lookup table for spoke thicknesses.

Jobst Brandt
[email hidden]

datakoll-<< the spokes will twang at a
different pitch, will different twangs produce a different tensions
using the tensionometers? >><BR><BR>

Yes why tone doesn't tell you tension, just if the spokes are close in tension
to each other...I think ...that's what you asked..

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

On 22 Jan 2005 15:06:17 GMT, [email hidden] (Qui si parla

Campagnolo ) said:

datakoll-<< the spokes will twang at a
different pitch, will different twangs produce a different tensions
using the tensionometers? >><BR><BR>

Yes why tone doesn't tell you tension, just if the spokes are close in tension
to each other...I think ...that's what you asked..

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

Dear Peter,

True. If the spokes are the same thickness and same length
and same tension, then they make the same note if plucked
because they vibrate at the same frequency.

What tension that note means varies.

If one spoke is thicker than the other, then it vibrates at
a lower frequency, just as a thicker and heavier violin
string vibrates at a lower pitch than a thinner string.
That's why the low-pitched G string is much thicker than the
high E string, even though they are the same length and are
at roughly the same tension.

(At the same length and tension, a thicker 2.0 mm spoke has
a lower note than a 1.8 mm spoke.)

If one spoke is shorter than the other, then it vibrates at
a higher frequency, just as a violin string makes a higher
sound when shortened by fingering--neither the thickness nor
the tension changes.

(At the same thickness and tension, a longer 280 mm spoke
makes a higher note than a 296 mm spoke. A spoke is
effectively fingered by any crossing of another spoke.)

And if one spoke is not as taut as another, then it vibrates
at a lower frequency, just as a violin string is tuned by
changing the string's tension by turning the tuning peg to
raise or lower the pitch.

(When tightened, the same spoke rises in pitch.)

If you want to tune your spokes to the standard 440 Hz A
above middle C, you can either hire an oboe player like an
orchestra or else just pick up the phone and listen to the
dial tone.

Carl Fogel

Quoted message said:

If you want to tune your spokes to the standard 440 Hz A
above middle C, you can either hire an oboe player like an
orchestra or else just pick up the phone and listen to the
dial tone.

Unfortunately, the dial tone also has a 350hz tone mixed in.

440/350 ~= 1.25714
2^(1/12) ~= 1.05946
1.05946^4 ~= 1.25992

So the dial tone is an out of tune major 3rd with an out of tune F and
an A.

Jim Smith said:

Quoted message said:

If you want to tune your spokes to the standard 440 Hz A
above middle C, you can either hire an oboe player like an
orchestra or else just pick up the phone and listen to the
dial tone.

Unfortunately, the dial tone also has a 350hz tone mixed in.

440/350 ~= 1.25714
2^(1/12) ~= 1.05946
1.05946^4 ~= 1.25992

So the dial tone is an out of tune major 3rd with an out of tune F and
an A.

Dear Jim,

True:

http://hypertextbook.com/physics/waves/beats/

Nice picture of an oscilliscope listening to a dial tone.

Carl Fogel