OK if spokes stick out of nipples?

(Qui si parla Campagnolo ) writes:

If the spoke nipple is engaging enough threads of the spoke, and you can true
the wheel. And if the end won't hit your rim strip and tube, it will be okay.

On the "engaging enough threads" issue: could insufficient thread
engagement be a possible cause of spoke breakage at the nipple? A
rear wheel I once built had two such failures, one after about 1500
miles and another less than 1000 miles later. At the time I did
some googling and a common reply about the cause was that the wheel
hadn't been stress relieved, but in this case the wheel had indeed
been stress relieved using the procedure in Jobst's book. The only
things I could think of that I did wrong were (1) I used spokes
that were too long, such that quite a bit was protuding from the
end of the nipple, (2) I neglected to correct the spoke line at the
rim, and (3) the spokes might have been too thin (see below). I
suppose defective spokes were a possibility, but I think a more
likely explanation was defective building.

Stats on the wheel in question: rear wheel, Chorus hub, Open Pro
rim, 32 spokes, cross 3, brass nipples, DT 1.8/1.6 (15/16ga) spokes,
rider weight about 150-155 lbs. I don't remember whether the spokes
that broke were pulling or pushing, but I think both were on the
drive side. I rebuilt the wheel using shorter and thicker spokes
(2.0/1.8 or 14/15ga) and made sure I corrected the spoke line, and
the wheel didn't have any problems thereafter.

Do you suppose insufficient thread engagement could have been the
principal cause of spoke failure at the nipple? Or was it more
likely the combined problems of too-long and too-thin spokes and
failure to correct the spoke line?

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

Michael Fuhr wrote:
(Qui si parla Campagnolo ) writes:
If the spoke nipple is engaging enough threads of the spoke, and you
can true the wheel. And if the end won't hit your rim strip and tube,
it will be okay.
On the "engaging enough threads" issue: could insufficient thread
engagement be a possible cause of spoke breakage at the nipple? A rear
wheel I once built had two such failures, one after about 1500 miles and
another less than 1000 miles later. At the time I did some googling and
a common reply about the cause was that the wheel hadn't been stress
relieved, but in this case the wheel had indeed been stress relieved
using the procedure in Jobst's book. The only things I could think of
that I did wrong were (1) I used spokes that were too long, such that
quite a bit was protuding from the end of the nipple, (2) I neglected to
correct the spoke line at the rim, and (3) the spokes might have been
too thin (see below). I suppose defective spokes were a possibility, but
I think a more likely explanation was defective building.
Stats on the wheel in question: rear wheel, Chorus hub, Open Pro rim, 32
spokes, cross 3, brass nipples, DT 1.8/1.6
(15/16ga) spokes, rider weight about 150-155 lbs. I don't remember
whether the spokes that broke were pulling or pushing, but I think
both were on the drive side. I rebuilt the wheel using shorter and
thicker spokes
(16./1.8 or 14/15ga) and made sure I corrected the spoke line, and the
wheel didn't have any problems thereafter.
Do you suppose insufficient thread engagement could have been the
principal cause of spoke failure at the nipple? Or was it more likely
the combined problems of too-long and too- thin spokes and failure to
correct the spoke line?
--
Michael Fuhr http://www.fuhr.org/~mfuhr/http://www.fuhr.org/~mfuhr/

Spokes stretch under tension . When properly tensioned they stretc
about 1 mm. Also, rims shrink in diameter due to spoke tension. I hav
seen rim shrinkage in the range of 1 to 2 mm. It is hard to measur
stretching of the spoke, but look at the charts in "the Book". You ca
measure rim shrinkage in a truing stand or other fixture that ha
stability sufficient for this type of measurement. Spokes should b
aligned at the hub and rim so they follow the same path a tight strin
would follow. If the nipple doesn't pivot within the rim to point at th
hub spoke hole, you need to improve the spoke line at the exit of th
nipple. There are good instructions and illustrations of before an
after in "the Book". Even the highest quality spokes have some sample
come through distribution where they have flaws that will show up late
with normal use. Some shops also do their own spoke cutting and ca
cause material flaws. Most quality spokes have 20 turns of threading.
quality build has all 20 turns engaged when the wheel is finished


-

"S. Anderson" wrote in message ...
" Doug Goncz " wrote in message
...
Oh, no, the spoke should initially tighten and true _below_ the slot. It's
gonna stretch. It should never be in the slot during it's whole service
lifetime.

Spokes stretch?? Here we go... ;-)

God, what a shriek as the stone hits the spoke. Don't have a bench grinder
at
home. Ear protection with the router.

For sure grinding is not the best solution. New spokes are. As you found
out, grinding is a pain in both the ass and ears! I consider it a bit of a
hack solution, but I always like perfection when it comes to bikes. But
given the right circumstances, it IS a solution. To me, it's a lot like
cutting a cable too long or too short. Still works but it looks bush
league. As long as you KNOW it's bush league...

Cheers,

Scott..

Dear Scott,

The trick is to use the over-priced reinforced fiberglass
cutting wheels. They're quite gentle on the ears, and you
can cut a car in half with enough of them.

What I long for is a Prazi-style dremel that somehow presents
the spinning wheel at 90 degrees to the normal rotation,
chainsaw-fashion, for getting into tight places.

It occurs to me that someone should mention that a ground-down
spoke will be just as strong as a normal spoke (only the first
few threads entering the nipple take the load)m but that it
will be almost impossible to thread into a new nipple. If
you ever unscrew it, have a replacement spoke handy.

Carl Fogel

"Carl Fogel" wrote in message Dear Scott,

The trick is to use the over-priced reinforced fiberglass
cutting wheels. They're quite gentle on the ears, and you
can cut a car in half with enough of them.

What I long for is a Prazi-style dremel that somehow presents
the spinning wheel at 90 degrees to the normal rotation,
chainsaw-fashion, for getting into tight places.

It occurs to me that someone should mention that a ground-down
spoke will be just as strong as a normal spoke (only the first
few threads entering the nipple take the load)m but that it
will be almost impossible to thread into a new nipple. If
you ever unscrew it, have a replacement spoke handy.

Carl Fogel

Or so you've heard, having never done such a thing yourself.. ;-)

Cheers!

Scott..

On Sat, 06 Mar 2004 22:06:51 GMT, "Jacobe Hazzard"
may have said:

I just built my first wheel. My LBS calculated the spoke lengths for me, and
gave me the same length for left and right (this is 7spd rear wheel, laced 3
cross). They told me I was in between sizes, but should be fine with what
they gave me.

Having built the wheel, the spokes on the right side protrude from the
nipples by around 1-1.5mm. Aside from the fact that the nipples can't be
turned from inside the rim with a screwdriver, is there any problem with
this? I'm really tempted to just throw on a rim elastic, slap a tire on the
wheel and call it finished.

If the wheel is designed so that the rim strip is bearing directly on
the tops of the nipples, and thereby also on the ends of the spokes,
then no, it is not OK to just throw a rim strip on it and go. You'll
have a holey tube in short order.

If the nipples sit in a recess or are accessed via a drilling in the
web above them, and the spoke ends don't come close to the hole, then
you may be able to get away with ignoring the protrusion, but that
doesn't make it right.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

(Michael Fuhr) wrote in message ...
(Qui si parla Campagnolo ) writes:

If the spoke nipple is engaging enough threads of the spoke, and you can true
the wheel. And if the end won't hit your rim strip and tube, it will be okay.

On the "engaging enough threads" issue: could insufficient thread
engagement be a possible cause of spoke breakage at the nipple? A
rear wheel I once built had two such failures, one after about 1500
miles and another less than 1000 miles later. At the time I did
some googling and a common reply about the cause was that the wheel
hadn't been stress relieved, but in this case the wheel had indeed
been stress relieved using the procedure in Jobst's book. The only
things I could think of that I did wrong were (1) I used spokes
that were too long, such that quite a bit was protuding from the
end of the nipple, (2) I neglected to correct the spoke line at the
rim, and (3) the spokes might have been too thin (see below). I
suppose defective spokes were a possibility, but I think a more
likely explanation was defective building.

Stats on the wheel in question: rear wheel, Chorus hub, Open Pro
rim, 32 spokes, cross 3, brass nipples, DT 1.8/1.6 (15/16ga) spokes,
rider weight about 150-155 lbs. I don't remember whether the spokes
that broke were pulling or pushing, but I think both were on the
drive side. I rebuilt the wheel using shorter and thicker spokes
(2.0/1.8 or 14/15ga) and made sure I corrected the spoke line, and
the wheel didn't have any problems thereafter.

Do you suppose insufficient thread engagement could have been the
principal cause of spoke failure at the nipple? Or was it more
likely the combined problems of too-long and too-thin spokes and
failure to correct the spoke line?

Dear Michael,

It's hard to find fault with the brands that you mention.
Drive-side spokes typically fail before others. Riders
your weight often do fine on 32 thinner spokes, according
to the idle rumors circulating around here.

If your spokes were protruding from the nipples, then you
had the maxium possible thread engagement. If they were
protruding three threads, that was likely causing problems.

Here's why.

Thread a loose DT spoke and nipple together by hand as far
as you can. When about three spoke threads stick out beyond
the nipple, you've gone as far as you can go because the
unthreaded spoke shaft has reached the beginning of the
threads inside the nipple.

(Lord knows that nipples and threading will vary, but I
tried this on my DT spokes just now.)

So possibly you tightened the nipples until you hit the end of
the spoke threads and then--you powerful devil!--kept tightening
the nipple against the end of the spoke-threads enough to strain
the spoke badly.

(Think of heaving on a nut that's reached the end of the thread
on a long bolt--heave hard enough and the bolt usually breaks.)

Or possibly you tightened nipples until they reached the end
of the spoke-thread, stopped, and were left with spokes that
couldn't be tightened any further, but hadn't reached the proper
tension.

(Think of riding on spokes that aren't tight enough, but can't
be tightened any further for lack of threads.)

Carl Fogel

"Jacobe Hazzard" wrote in message . cable.rogers.com...

[snip Carl]

Well I did it. I couldn't for the life of me figure out how to use cutting
discs to cut off the ends of spokes that were already in the wheel, (even my
left over little tiny worn down discs wouldn't fit) so I used a pink
grinding wheel. I removed less than 1mm from most of the spokes, so
hopefully I will have enough threads left and no problems later on. I just
coulnd't wait till tomorrow to visit the bike shop and get new spokes, let
me explain:


[snip non-dremel matters]

Dear Jacob,

Possibly you were using those vile, thin, un-reinforced
cutoff disks that come with a dremel tool?

If I were to assault a protruding spoke with a dremel
tool, I'd wield a reinforced fiberglass cutting wheel.
(They're thicker, sturdier, and much more expensive
than those sissified cutoff disks--and darn well worth
it. They don't break and are wide enough to do some
damage.)

And I wouldn't try to cut the protruding spoke off,
which would be tricky, if not impossible.

Instead, I'd just lower the edge of the reinforced
cutting wheel onto the head of the spoke and obliterate
it in a couple of seconds, grinding the spoke down
flush with the nipple.

Not, of course, that I'd ever do such a thing.

Carl Fogel

On 7 Mar 2004 12:17:03 -0800, (Carl Fogel)
wrote:
The trick is to use the over-priced reinforced fiberglass
cutting wheels. They're quite gentle on the ears, and you
can cut a car in half with enough of them.

I have the diamond-covered-metal wheels, and they are fine sounding,
but I'm used to much bigger machinery. However, for the spokes, I
might use a grinding wheel instead. One like
http://www.dremel.com/html/images/pr...large/8193.gif
is good; you can use the side as shown, or the end of it works too.

What I long for is a Prazi-style dremel that somehow presents
the spinning wheel at 90 degrees to the normal rotation,
chainsaw-fashion, for getting into tight places.

Here's more grinding bits that you can use from different angles:
http://www.dremel.com/html/images/pr.../large/953.gif
http://www.dremel.com/html/images/pr.../large/971.gif
http://www.dremel.com/html/images/pr.../large/903.gif
--
Rick Onanian