Spoke threads exposed on new wheel - Safe?

http://www.yellowjersey.org/photosfr...st/NIPPLES.JPG

I didn't know when I wrote that that DT has since changed to
4mm extra thread in the long nipples.

It's not as much as much as 4mm but the DT 16mm nipples I recently
bought do have more thread than 12mm nipples. Might be just enough
to make the difference between success and failure with some
too-short spokes.

My DT 16mm spokes have 4.5 more threads (whole turns).

Assuming 56 TPI, that'll be 2mm more thread.

~PB

wrote:

DT 2.0 x 16mm have 22.5 turns worth of thread, 12mm have 18.

That's not the way it was supposed to work. That would require a
different spoke length for the same ERD but different nipple lengths.
I hope someone who doesn't build wheels didn't mess this up. As you
see from this thread, ones first impression is that the threads should
be longer, when in reality they should not, all rim ERD's requiring
the same length spoke regardless of nipple type.

From DT's online Spoke Calculator Instructions
www.dtswiss.com/index.asp?fuseaction=spokes.bike :

"When using 14 mm nipples (e.g. Mavic CXP 33) about 1 mm has to be
deducted from the established spoke length."

"When using 16 mm nipples (e.g. Mavic CXP 30) about 3 mm have to be
deducted from the established spoke length."

I can see how this adds complication to calculation but is there a
disadvantage for the wheel of using shorter spokes with longer-threaded
nipples?

That you found nipples with more thread is a boon to those who
miscalculate their spoke lengths

(That was the only purpose to my first reply, although this whole subject
is now interesting)

, but is a loss to those who did it
correctly and wanted to use these nipples because their rim cross
section required a longer reach nipple.

But when they take this into account and get shorter spokes?

~PB

I thought that it would be best if the spoke went to the end of the
nipple to better support and prevent cracking of the nipple head from
the shank, because of the change in cross-sectional area.
Dave Balfour
(Qui si parla Campagnolo) wrote in message ...
andy- http://www.yellowjersey.org/photosfr...st/NIPPLES.JPG

I didn't know when I wrote that that DT has since changed to
4mm extra thread in the long nipples.
BRBR

'so 'kay-I have used a bunch of DT 16mm nipps when building CXP-30s when they
were the rave...

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

Mark Vieselmeyer wrote in message ...
B.C. Cletta wrote:
: or (B): simply measure the depth of the hole from the bead diameter,
: 622-mm for a 700c. don't forget to 2x it.

Is that 622mm consistent for different rims? When I swap my front and rear
wheels on my truing stand, I have to adjust the vertical truing doohickey by
about 1mm.

- mark

the bead diameter is the (most or less) flat shelf inside the rim
were the tire seats. see the rim profiles (where esle?):
http://www.sheldonbrown.com/harris/rims.html
what i do is stick my calipers in the rim, twist a little sideways
so it hit the flats & sidewall, push down the depth probe, repeat a
couple of times.
remember that spokes are usually bought in 2-mm steps so +/- 1-mm is
acceptable.
what's the doohickey hitting, the top of the rim's sidewalls? my
guess is that the distance from the bead diameter to the hook is a
constant for tire support & "safety" but it's a guess.

wishbone- I thought that it would be best if the spoke went to the end of the
nipple to better support and prevent cracking of the nipple head from
the shank BRBR

What I shoot for but the OP was terying to make up for too short spokes, where
166mm DT nipps may work. Don't really know as I have not seen the wheel but I
would try the $3.20 type of fix first.

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

B.C. Cletta wrote:
: Mark Vieselmeyer wrote in message ...
: B.C. Cletta wrote:
: : or (B): simply measure the depth of the hole from the bead diameter,
: : 622-mm for a 700c. don't forget to 2x it.
:
: Is that 622mm consistent for different rims? When I swap my front and rear
: wheels on my truing stand, I have to adjust the vertical truing doohickey by
: about 1mm.
:
: - mark

: the bead diameter is the (most or less) flat shelf inside the rim
: were the tire seats. see the rim profiles (where esle?):
: http://www.sheldonbrown.com/harris/rims.html
: what i do is stick my calipers in the rim, twist a little sideways
: so it hit the flats & sidewall, push down the depth probe, repeat a
: couple of times.
: remember that spokes are usually bought in 2-mm steps so +/- 1-mm is
: acceptable.
: what's the doohickey hitting, the top of the rim's sidewalls? my

Yes.

: guess is that the distance from the bead diameter to the hook is a
: constant for tire support & "safety" but it's a guess.

When I get a chance I'll take a closer look and see if I can identify where
the difference lies. One thing that occurred to me is that spreading the
stand's fork to fit the rear wheel's axle would give a slight downward
offset, which would be toward the doohickey, although if I remember
correctly it's the rear wheel that seems to have the smaller diameter, so
the offset is in the wrong direction.

Of course the other possibility is that I inadvertently knocked the stand
out of adjustment while swapping wheels. I don't think that's the case, but
I'll be sure to watch it when I re-measure.

Another thing that just occurred to me is that the axels could be different
diameters, so I'll measure that as well.

- mark

Mark Vieselmeyer wrote in message ...
B.C. Cletta wrote:
: Mark Vieselmeyer wrote in message ...
: B.C. Cletta wrote:
: : or (B): simply measure the depth of the hole from the bead diameter,
: : 622-mm for a 700c. don't forget to 2x it.
:
: Is that 622mm consistent for different rims? When I swap my front and rear
: wheels on my truing stand, I have to adjust the vertical truing doohickey by
: about 1mm.
:
: - mark

: the bead diameter is the (most or less) flat shelf inside the rim
: were the tire seats. see the rim profiles (where esle?):
: http://www.sheldonbrown.com/harris/rims.html
: what i do is stick my calipers in the rim, twist a little sideways
: so it hit the flats & sidewall, push down the depth probe, repeat a
: couple of times.
: remember that spokes are usually bought in 2-mm steps so +/- 1-mm is
: acceptable.
: what's the doohickey hitting, the top of the rim's sidewalls? my

Yes.

: guess is that the distance from the bead diameter to the hook is a
: constant for tire support & "safety" but it's a guess.

When I get a chance I'll take a closer look and see if I can identify where
the difference lies. One thing that occurred to me is that spreading the
stand's fork to fit the rear wheel's axle would give a slight downward
offset, which would be toward the doohickey, although if I remember
correctly it's the rear wheel that seems to have the smaller diameter, so
the offset is in the wrong direction.

the axle diameter difference is 9-mm front vs 10-mm rear, i.e.,
budkes.

Of course the other possibility is that I inadvertently knocked the stand
out of adjustment while swapping wheels. I don't think that's the case, but
I'll be sure to watch it when I re-measure.

Another thing that just occurred to me is that the axels could be different
diameters, so I'll measure that as well.

- mark

at times i tempted to make a jig to use the bead diameter for
centering the wheel. or i could go for a ride.

B.C. Cletta wrote:
: Mark Vieselmeyer wrote in message ...

: When I get a chance I'll take a closer look and see if I can identify where
: the difference lies. One thing that occurred to me is that spreading the
: stand's fork to fit the rear wheel's axle would give a slight downward
: offset, which would be toward the doohickey, although if I remember
: correctly it's the rear wheel that seems to have the smaller diameter, so
: the offset is in the wrong direction.

: the axle diameter difference is 9-mm front vs 10-mm rear, i.e.,
: budkes.

Well, it does account for a half-mm difference at the 6-o'clock position,
which is still not enough, even before considering that the doohickey is at
4-o'clock.

: Of course the other possibility is that I inadvertently knocked the stand
: out of adjustment while swapping wheels. I don't think that's the case, but
: I'll be sure to watch it when I re-measure.
:
: Another thing that just occurred to me is that the axels could be different
: diameters, so I'll measure that as well.

: at times i tempted to make a jig to use the bead diameter for
: centering the wheel. or i could go for a ride.

But the truing stand should be able to serve as a jig. I still can't find
sufficient discrepencies to account for the difference, so I'm fairly certain
at this point that the wheel diameters really are different. So now I
_can't_ go ride, because obviously my tire isn't going to stay on the rim
(plus it's really cold out).

- mark

On 5 Nov 2003 15:02:25 -0700, Mark Vieselmeyer
wrote:

B.C. Cletta wrote:
"Felix qui potuit rerum cognoscere causas". - (Vergil)
: Mark Vieselmeyer wrote in message ...

: When I get a chance I'll take a closer look and see if I can identify where
: the difference lies. One thing that occurred to me is that spreading the
: stand's fork to fit the rear wheel's axle would give a slight downward
: offset, which would be toward the doohickey, although if I remember
: correctly it's the rear wheel that seems to have the smaller diameter, so
: the offset is in the wrong direction.

: the axle diameter difference is 9-mm front vs 10-mm rear, i.e.,
: budkes.

Well, it does account for a half-mm difference at the 6-o'clock position,
which is still not enough, even before considering that the doohickey is at
4-o'clock.

: Of course the other possibility is that I inadvertently knocked the stand
: out of adjustment while swapping wheels. I don't think that's the case, but
: I'll be sure to watch it when I re-measure.
:
: Another thing that just occurred to me is that the axels could be different
: diameters, so I'll measure that as well.

: at times i tempted to make a jig to use the bead diameter for
: centering the wheel. or i could go for a ride.

But the truing stand should be able to serve as a jig. I still can't find
sufficient discrepencies to account for the difference, so I'm fairly certain
at this point that the wheel diameters really are different. So now I
_can't_ go ride, because obviously my tire isn't going to stay on the rim
(plus it's really cold out).

The discrepencies you see come from two sources:

1- the difference in the ordinary diameters of front (9 mm)
and rear (10 mm) axles. Your earlier exchanges already acknowledge
this.

2- If your truing jig holds the axle ends in a vee-shaped
notch at each end (as most do), the greater diameter of the rear axle
keeps it seated a little higher up in the vee than is the case with
front axles. That's why the roundness feeler gauge is off by more than
just half the axle diameter difference when you change from front to
rear.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Now in our twenty-first year.
Our catalog of track equipment: eighth year online.
http://www.businesscycles.com

Mark Vieselmeyer wrote:
But the truing stand should be able to serve as a jig. I still can't find
sufficient discrepencies to account for the difference, so I'm fairly certain
at this point that the wheel diameters really are different. So now I
_can't_ go ride, because obviously my tire isn't going to stay on the rim
(plus it's really cold out).


I think you are trying to say that your truing stand hits
the front rim differently from your rear rim. The variance
of rim sections within an ISO size is pretty great. Did you
try to mount the tire? What kind (brand/model) of rims are
we talking about?

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