Spoke Length: Measurement Methology And Criticality?

Michael Press

In article
<259b91e0-e5f3-47dc-a38d-13f3c0c76e10@q78g2000hsh.googlegroups.com>,
datakoll <datakoll@yahoo.com> wrote:

> well, I guess its ok to ask this now.
> JB sez the Rohloff takes a 2 cross lacing. Does that mean the Rohloff
> isnot indicated for rough over the road long distance riding?

He's saying that the Rohloff flange can handle 1x,
and that the spoke angle into the rim is much
more stressful running 3x from the Rohloff contrasted
with 1x or 2x.

Spoke crossing is inconsequential to ride
quality. Spoke crossing is designed to
reduce stress on the hub flange.

--
Michael Press

Clive George

<jobst.brandt@stanfordalumni.org> wrote in message
news:47bf95e7$0$36363$742ec2ed@news.sonic.net...
> Clive George writes:
>
>>>>> cross patten
>
>>>> Given that the pattern recommended for/(by?) Rohloff is 2x and the
>>>> Rohloff flange's diameter is only 9 mm more than the Sturmey's,
>>>> what's your take on the tradeoffs between 2x and 3x for the
>>>> Sturmey (front wheel...)?
>
>>> That's a mighty small text cite from which to guess to what you are
>>> referring. I also don't know what the SA hub you refer to is or
>>> how many spokes. This seems to be cryptology.
>
>> Apparently it's a new SA Dynohub. Flange diameter 92mm at the
>> outside of the spoke holes. 61mm across the outside of the flanges
>> (ie. the spacing). 36H. 26" rim.
>
>> So, 3x or 2X? (I'd go with 3 out of habit).
>
> If it is a steel flange hub, I would go with the lower cross pattern
> or even radial, there being no hazard of the flange failure. My old
> SA Dynohub is spoked radial on the large flange (magnet side) and
> cross three on the small flange of the other side because it has
> keyhole spoke holes so one can insert them elbow first.
>
> Is there a convenient picture of this hub that I might see?

There's Pete's photos too -

http://tinyurl.com/3a9t2z

http://tinyurl.com/3e3r8g

http://tinyurl.com/2ofbyz

It's a new hub, not the old SA one, so it's Al, not steel. So pretty
comparable to the current shimano and SON hubs.

cheers,
clive

Tom Sherman

jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> Carl Fogel writes:
>
>>>>> cross patten
>
>>>> Given that the pattern recommended for/(by?) Rohloff is 2x and the
>>>> Rohloff flange's diameter is only 9 mm more than the Sturmey's,
>>>> what's your take on the tradeoffs between 2x and 3x for the Sturmey
>>>> (front wheel...)?
>
>>> That's a mighty small text cite from which to guess to what you are
>>> referring. I also don't know what the SA hub you refer to is or how
>>> many spokes. This seems to be cryptology.
>
>>> It the flanges can withstand the load radially, then a low cross
>>> number is preferable. Small flange racing hubs occasionally fail
>>> radially from 36x3 spoking.
>
>> If you're interested, you could learn to use Google or to ask
>> politely.
>
> What is impolite in that response? You sit idly by as anonymous
> contributors call others rude names and call them liars and now you
> call this response impolite, if I understand what you wrote. Beyond
> that, you think I should do a web search to discover what the
> questioner is talking about.
>
>> Here's a freebie:
>
> http://www.rohloff.de/en/technical/...gths/index.html
>
>> Cheers,
>
> You're not being cheery today, regardless of your style of response.
> In this thread, I saw no previous reference to front wheel hubs, the
> ones in question. I don't memorize what the beginning of the thread
> contained, and it didn't, but citations of germane parts of the thread
> are included in these exchanges for the purpose of clarity and
> context. You might direct your criticism to those who clip ALL and
> ask vague questions.
>
> With a bit more information, I could make spoking suggestions beyond
> the general ones I gave.
>
The actual hub comes out several posts from the original. The hub in
question appears to be the Sturmey Archer X-FDD Dynohub:
<http://www.sturmey-archer.com/hubs_fh_XFDD.php>.

From the SA webpage:

X-FDD

Description

• Front Dynamo Hub with 70mm Drum Brake
• Available with either Sealed Cartridge Bearings or Open Ball Cage Bearings
• Available in 2.4W or 3.0W

Specs for Open Ball Cage 2.4W

• Model # HDS20TBSSAA0
• Voltage - 6V
• Output - 2.4W
• Hub Shell Material - 6061 Aluminum
• Bearing Type - Open Ball Cage
• Axle Diameter - 9mm
• Axle Length - 140.0mm
• Over Locknut Dimension - 100.0mm
• Spoke Holes - 36
• Pitch Circle Diameter - 89.8mm
• Flange Width - 56.5mm
• Offset - 0
• Spoke Compatibility - 13g or 14g

Specs for Open Ball Cage 3.0W

• Model # HDS30TBSSAA0
• Voltage - 6V
• Output - 3.0W
• Hub Shell Material - 6061 Aluminum
• Bearing Type - Open Ball Cage
• Axle Diameter - 9mm
• Axle Length - 140.0mm
• Over Locknut Dimension - 100.0mm
• Spoke Holes - 36
• Pitch Circle Diameter - 89.8mm
• Flange Width - 56.5mm
• Offset - 0
• Spoke Compatibility - 13g or 14g

Specs for Sealed Cartridge 2.4W

• Model # HDS21TBSSAA0
• Voltage - 6V
• Output - 2.4W
• Hub Shell Material - 6061 Aluminum
• Bearing Type - Sealed Cartridge
• Axle Diameter - 9mm
• Axle Length - 140.0mm
• Over Locknut Dimension - 100.0mm
• Spoke Holes - 36
• Pitch Circle Diameter - 89.8mm
• Flange Width - 56.5mm
• Offset - 0
• Spoke Compatibility - 13g or 14g

Specs for Sealed Cartridge 2.4W

• Model # HDS31TBSSAA0
• Voltage - 6V
• Output - 3.0W
• Hub Shell Material - 6061 Aluminum
• Bearing Type - Sealed Cartridge
• Axle Diameter - 9mm
• Axle Length - 140.0mm
• Over Locknut Dimension - 100.0mm
• Spoke Holes - 36
• Pitch Circle Diameter - 89.8mm
• Flange Width - 56.5mm
• Offset - 0
• Spoke Compatibility - 13g or 14g

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

(PeteCresswell)

Per Clive George:
>I'm guessing 268 for 4x. Personally I'd use 3x, so 254mm. Spocalc with your
>numbers doesn't give 244 or 246 either.

Major case of RCI on my part.

Having totally missed the SpoCalc instruction page, I was trying
to operate it using somebody else's measurement conventions.

Now I've done it the right way.

Your 254 seems tb right on the money.

SpoCalc gives me 252.7 and 252.9 (there's 1.5mm of dish in the
hub)

Pete Gray's SpokuLator gives 253.4.
http://www.houseof3d.com/pete/apple...l/appwheel.html


For 2x, 239.6/239.8 and 240.4 from Pete Gray.

Coincidentally, the few replacement spokes I have laying around
for my Rohloff wheels are 238's.

In the interest of compatibility/spare spokes, I'm tempted to get
238's and lace it 2x. Jobst said something about 2x being
preferable if the hub can take it - not that "preferable" is a
factor in a bike used as this one is...

I'm guessing the "small flange racing hubs" that he refers to as
occasionally failing are in a whole different (lower) class of
strength from the Sturmey DynoHub.
--
PeteCresswell

Ben C

On 2008-02-22, datakoll <datakoll@yahoo.com> wrote:
> well, I guess its ok to ask this now.
> JB sez the Rohloff takes a 2 cross lacing. Does that mean the Rohloff
> isnot indicated for rough over the road long distance riding?

I should think it's 2 cross because the hub flange diameter is much
bigger than usual.

jobst.brandt@stanfordalumni.org

Pete Cresswell writes:

>> I'm guessing 268 for 4x. Personally I'd use 3x, so 254mm. Spocalc
>> with your numbers doesn't give 244 or 246 either.

> Major case of RCI on my part.

> Having totally missed the SpoCalc instruction page, I was trying to
> operate it using somebody else's measurement conventions.

> Now I've done it the right way.

> Your 254 seems to be right on the money.

> SpoCalc gives me 252.7 and 252.9 (there's 1.5mm of dish in the hub)

> Pete Gray's SpokuLator gives 253.4.

http://www.houseof3d.com/pete/apple...l/appwheel.html

> For 2x, 239.6/239.8 and 240.4 from Pete Gray.

> Coincidentally, the few replacement spokes I have laying around for
> my Rohloff wheels are 238's.

Were they laying eggs?

> In the interest of compatibility/spare spokes, I'm tempted to get
> 238's and lace it 2x. Jobst said something about 2x being
> preferable if the hub can take it - not that "preferable" is a
> factor in a bike used as this one is...

With such widely spaced spoke holes and 36 spokes, tension of radial
spokes will not damage the flanges. However, braking forces require
x1 or x2. Torque on a hub with radial spoking will cause a
significant increase in spoke tension while braking. That will not
occur with cross laced spoking, even x1.

> I'm guessing the "small flange racing hubs" that he refers to as
> occasionally failing are in a whole different (lower) class of
> strength from the Sturmey DynoHub.

Campagnolo record hubs do that. I have examples.

Jobst Brandt

A Muzi

(PeteCresswell) wrote:
> Major case of RCI on my part.

-snip-
Radio Canada International?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

carlfogel@comcast.net

On Sat, 23 Feb 2008 13:18:43 -0600, A Muzi <am@yellowjersey.org>
wrote:

>(PeteCresswell) wrote:
>> Major case of RCI on my part.
>
>-snip-
>Radio Canada International?

Dear Andrew,

Rectal Cranial Inversion.

(Yes, it's really an acronym.

Cheers,

Carl Fogel

(PeteCresswell)

Per jobst.brandt@stanfordalumni.org:
>Torque on a hub with radial spoking will cause a
>significant increase in spoke tension while braking. That will not
>occur with cross laced spoking, even x1.
>
>> I'm guessing the "small flange racing hubs" that he refers to as
>> occasionally failing are in a whole different (lower) class of
>> strength from the Sturmey DynoHub.
>
>Campagnolo record hubs do that. I have examples.

So... bottom line.... You wouldn't have any second thoughts about
lacing 2x on a Dynohub wheel?

It's not a religious issue or anything... just seems that if I'm
going to have 30+ spokes left over from a box of 75 it will be
more aesthetic for them to fit three of my wheels instead of one.
Also, I wonder if there is some hub-diameter-related engineering
reason why Rohloff recommends 2x.
--
PeteCresswell

(PeteCresswell)

Per A Muzi:
>(PeteCresswell) wrote:
>> Major case of RCI on my part.
>
>-snip-
>Radio Canada International?
>--

Recto-Cranial Inversion
--
PeteCresswell

A Muzi

> Per jobst.brandt@stanfordalumni.org:
>> Torque on a hub with radial spoking will cause a
>> significant increase in spoke tension while braking. That will not
>> occur with cross laced spoking, even x1.
>>
>>> I'm guessing the "small flange racing hubs" that he refers to as
>>> occasionally failing are in a whole different (lower) class of
>>> strength from the Sturmey DynoHub.
>> Campagnolo record hubs do that. I have examples.

(PeteCresswell) wrote:
> So... bottom line.... You wouldn't have any second thoughts about
> lacing 2x on a Dynohub wheel?
> It's not a religious issue or anything... just seems that if I'm
> going to have 30+ spokes left over from a box of 75 it will be
> more aesthetic for them to fit three of my wheels instead of one.
> Also, I wonder if there is some hub-diameter-related engineering
> reason why Rohloff recommends 2x.

Right. As the drill count goes up and/or the flange size goes down, one
is left with not much material between spoke holes. Big flanges don't
exhibit flange cracking like 36h small flange do. A classic bad example
is an original tiny flange Hi-E 36h front radial. They commit suicide
without encouragement.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

jobst.brandt@stanfordalumni.org

Pete Cresswell writes:

>> Torque on a hub with radial spoking will cause a significant
>> increase in spoke tension while braking. That will not occur with
>> cross laced spoking, even x1.

>>> I'm guessing the "small flange racing hubs" that he refers to as
>>> occasionally failing are in a whole different (lower) class of
>>> strength from the Sturmey DynoHub.

>> Campagnolo record hubs do that. I have examples.

> So... bottom line... You wouldn't have any second thoughts about
> lacing 2x on a Dynohub wheel?

No problem.

> It's not a religious issue or anything... just seems that if I'm
> going to have 30+ spokes left over from a box of 75 it will be
> more aesthetic for them to fit three of my wheels instead of one.
> Also, I wonder if there is some hub-diameter-related engineering
> reason why Rohloff recommends 2x.

That's a good reason for selecting a spoke pattern, so long as it
doesn't adversely affect spoke durability, which this probably
doesn't. Just keep an eye on the spoke line into spoke nipples and,
if necessary, improve that spoke line manually.

Jobst Brandt

jim beam

jobst.brandt@stanfordalumni.org wrote:
> Pete Cresswell writes:
>
>>> Torque on a hub with radial spoking will cause a significant
>>> increase in spoke tension while braking. That will not occur with
>>> cross laced spoking, even x1.
>
>>>> I'm guessing the "small flange racing hubs" that he refers to as
>>>> occasionally failing are in a whole different (lower) class of
>>>> strength from the Sturmey DynoHub.
>
>>> Campagnolo record hubs do that. I have examples.
>
>> So... bottom line... You wouldn't have any second thoughts about
>> lacing 2x on a Dynohub wheel?
>
> No problem.
>
>> It's not a religious issue or anything... just seems that if I'm
>> going to have 30+ spokes left over from a box of 75 it will be
>> more aesthetic for them to fit three of my wheels instead of one.
>> Also, I wonder if there is some hub-diameter-related engineering
>> reason why Rohloff recommends 2x.
>
> That's a good reason for selecting a spoke pattern, so long as it
> doesn't adversely affect spoke durability, which this probably
> doesn't. Just keep an eye on the spoke line into spoke nipples and,
> if necessary, improve that spoke line manually.
>

how are you going to do that without introducing residual stress?

Michael Press

In article <F9idnf4l-uXpPl3anZ2dnUVZ_vzinZ2d@speakeasy.net>,
jim beam <spamvortex@bad.example.net> wrote:

> jobst.brandt@stanfordalumni.org wrote:
> > Pete Cresswell writes:
> >
> >>> Torque on a hub with radial spoking will cause a significant
> >>> increase in spoke tension while braking. That will not occur with
> >>> cross laced spoking, even x1.
> >
> >>>> I'm guessing the "small flange racing hubs" that he refers to as
> >>>> occasionally failing are in a whole different (lower) class of
> >>>> strength from the Sturmey DynoHub.
> >
> >>> Campagnolo record hubs do that. I have examples.
> >
> >> So... bottom line... You wouldn't have any second thoughts about
> >> lacing 2x on a Dynohub wheel?
> >
> > No problem.
> >
> >> It's not a religious issue or anything... just seems that if I'm
> >> going to have 30+ spokes left over from a box of 75 it will be
> >> more aesthetic for them to fit three of my wheels instead of one.
> >> Also, I wonder if there is some hub-diameter-related engineering
> >> reason why Rohloff recommends 2x.
> >
> > That's a good reason for selecting a spoke pattern, so long as it
> > doesn't adversely affect spoke durability, which this probably
> > doesn't. Just keep an eye on the spoke line into spoke nipples and,
> > if necessary, improve that spoke line manually.
> >
>
> how are you going to do that without introducing residual stress?

Apparently jb does not understand this as well as he has
professed. The answer is that the final manual stress relief
will insure that the residual stress plus cyclic stress
will not bring the spoke near yield.

--
Michael Press