spokes breaking on rear wheel

Joel said:

About 6 months ago I rebuilt my rear wheel using the existing Shimano
Ultegra hub and new DT double butted spokes and Velocity Aerohead OC
rim. The reason for the rebuild was because I was occasionally breaking
a nipple and the rim was beat up. Shortly after the rebuild I broke a
spoke, and now about every month or two I break a spoke. The break is
always near the nipple. The wheel is built 3 cross. After looking at
the wheel I noticed that there is an angle where the spoke enters the
nipples on some spokes but not others. I think the reason for the angle
is the 3 cross pattern on a 28H wheel. For some reason I did not have
this problem before I rebuilt the wheel. Now I am thinking I should
rebuild it again using 2 cross the lessen the spoke angle. My question
is can I rebuild on the same hub and change from 3 cross to 2 cross, or
is that a problem because of the grooves worn into the hub flanges by
the existing spokes?

Thanks - Joel

not a problem but re-seating will occur.

for the rim, try running a drill at an angle through the rim holes to
better align the nipple. or use a skinnier shouldered nipple like sapim.

Joel said:

About 6 months ago I rebuilt my rear wheel using the existing Shimano
Ultegra hub and new DT double butted spokes and Velocity Aerohead OC
rim. The reason for the rebuild was because I was occasionally breaking
a nipple and the rim was beat up. Shortly after the rebuild I broke a
spoke, and now about every month or two I break a spoke. The break is
always near the nipple. The wheel is built 3 cross. After looking at
the wheel I noticed that there is an angle where the spoke enters the
nipples on some spokes but not others. I think the reason for the angle
is the 3 cross pattern on a 28H wheel. For some reason I did not have
this problem before I rebuilt the wheel. Now I am thinking I should
rebuild it again using 2 cross the lessen the spoke angle. My question
is can I rebuild on the same hub and change from 3 cross to 2 cross, or
is that a problem because of the grooves worn into the hub flanges by
the existing spokes?

Thanks - Joel

You are right about what the problem is. This is one of the reasons why
3x isn't usually used on 28h hubs. This issue can generally be dealt
with fine by cold-setting the spokes to have a permanent bend where
they're currently forced to have a curve. This is done during the
wheelbuilding process after the spokes have a fair amount of tension,
but below final tension. It's done by squeezing together pairs of
spokes that cross with the closest crossing to the rim. You can check
out the Bicycle Wheel or some (many) of Jobst Brandt's previous
postings for more info.

Your spokes have been experiencing excess fatigue in the spots where
they're breaking, so whether doing this now will work or just
accelarate the breakage of some or all of the affected spokes is
something of a grey area, at least to me. It probably won't work very
well, especially on spokes that were part of the original build but
haven't broken yet.

The reason you didn't have this problem in the past could be either
because the wheel had the spoke line corrected at the nipple as
mentioned above when it was built the first time, or because the rim
had spoke holes that allowed for more nipple swivel than Aeroheads, or
both.

Rebuilding the wheel 2x means putting another set of grooves in the
hub, which can and sometimes, fairly unpredictably, does lead to
breakage of the flange. Opinions and practices vary quite a bit about
this, but in general it sucks and isn't a very good solution. That the
wheel is getting ridden hard enough, or just enough, for all the spoke
breakage to occur probably makes your hub as likely to fall apart
because of this if you rebuild it 2x as any.

Some people or suspicious of the way I described of correcting spoke
line at the rim, but it works very well, and can be pushed to extremes
further than can really be encountered on a 700 or 26" wheel.

Joel said:

About 6 months ago I rebuilt my rear wheel using the existing Shimano
Ultegra hub and new DT double butted spokes and Velocity Aerohead OC
rim. The reason for the rebuild was because I was occasionally breaking
a nipple and the rim was beat up. Shortly after the rebuild I broke a
spoke, and now about every month or two I break a spoke. The break is
always near the nipple. The wheel is built 3 cross. After looking at
the wheel I noticed that there is an angle where the spoke enters the
nipples on some spokes but not others. I think the reason for the angle
is the 3 cross pattern on a 28H wheel. For some reason I did not have
this problem before I rebuilt the wheel. Now I am thinking I should
rebuild it again using 2 cross the lessen the spoke angle. My question
is can I rebuild on the same hub and change from 3 cross to 2 cross, or
is that a problem because of the grooves worn into the hub flanges by
the existing spokes?

Thanks - Joel

I think you laced it into the wrong holes on the rim. Look at the
outside of the rim and notice the holes are offset to one side, on the
outside, that means a hole to the right, is for the spoke to the left
side of the rim..Also use brass nipps. 2 cross is preferable due to
spoke overlap onto the hub with 28h...but I would look at the hole
positioning first.

Qui si parla Campagnolo said:

Look at the
outside of the rim and notice the holes are offset to one side, on the
outside, that means a hole to the right, is for the spoke to the left
side of the rim..

Am I reading that wrong? I think you meant to say, "The rim holes that
are offset to the right go to the right flange of the hub.

Art Harris

Art Harris said:

Qui si parla Campagnolo said:

Look at the
outside of the rim and notice the holes are offset to one side, on the
outside, that means a hole to the right, is for the spoke to the left
side of the rim..

Am I reading that wrong? I think you meant to say, "The rim holes that
are offset to the right go to the right flange of the hub.

Art Harris

By "outside" he meant the tire side of the rim. Looking at the rim that
way on most or all v-section rims, holes offset to the right on the rim
go to the left flange, and vice versa.

So if I am reading this right, the spokes from a given flange go to the
hole in the rim that is offset furthest away from that flange which
would result in a greater bracing angle. I think is contrary to what is
stated in Jobst's book.
If that is the correct way to lace this rim then I got it wrong. Could
that account for the spoke breakage?

Joel

Nate Knutson said:

Art Harris said:

Qui si parla Campagnolo said:

Look at the
outside of the rim and notice the holes are offset to one side, on the
outside, that means a hole to the right, is for the spoke to the left
side of the rim..

Am I reading that wrong? I think you meant to say, "The rim holes that
are offset to the right go to the right flange of the hub.

Art Harris

By "outside" he meant the tire side of the rim. Looking at the rim that
way on most or all v-section rims, holes offset to the right on the rim
go to the left flange, and vice versa.

The spokes from a given flange do go to the holes in the rim that are
closest to that flange, on the hub side of the rim (could be called the
inside of the rim, well side, spoke side, and some other things). For
most or all v-section rims, if you look at the rim from the other side,
those holes are on the other side of the rim by necessity. I can't
remember offhand how pronounced this is on Aerohead OC's. It sounds
like your wheel is fine in this regard.

Joel said:

So if I am reading this right, the spokes from a given flange go to the
hole in the rim that is offset furthest away from that flange which
would result in a greater bracing angle. I think is contrary to what is
stated in Jobst's book.
If that is the correct way to lace this rim then I got it wrong. Could
that account for the spoke breakage?

Joel

Nate Knutson said:

Art Harris said:

Qui si parla Campagnolo wrote:
> Look at the
> outside of the rim and notice the holes are offset to one side, on the
> outside, that means a hole to the right, is for the spoke to the left
> side of the rim..

Am I reading that wrong? I think you meant to say, "The rim holes that
are offset to the right go to the right flange of the hub.

Art Harris

By "outside" he meant the tire side of the rim. Looking at the rim that
way on most or all v-section rims, holes offset to the right on the rim
go to the left flange, and vice versa.

Art Harris said:

Qui si parla Campagnolo said:

Look at the
outside of the rim and notice the holes are offset to one side, on the
outside, that means a hole to the right, is for the spoke to the left
side of the rim..

Am I reading that wrong? I think you meant to say, "The rim holes that
are offset to the right go to the right flange of the hub.

Art Harris

NO....Holes in rims are drilled so that when you look at the holes on
THESE rims, the hole on the oitside is to the right but the hole on
INSIDE the rim is to the left...MANY mistake the holes on the outside
of the rim as proper side but the holes are drilled outide->in, Tthink
of a drill making a hole at an angle, angled right on the oitside of
the rim, that makes for a hole offset to the left on the inside of the
rim.

Qui si parla Campagnolo said:

NO....Holes in rims are drilled so that when you look at the holes on
THESE rims, the hole on the oitside is to the right but the hole on
INSIDE the rim is to the left...MANY mistake the holes on the outside
of the rim as proper side but the holes are drilled outide->in, Tthink
of a drill making a hole at an angle, angled right on the oitside of
the rim, that makes for a hole offset to the left on the inside of the
rim.

Gotcha. Thanks for clearing that up.

Art Harris