interleaving the spokes- what good does it actually do?

[dabac]

Hi guys,

Read some loose claims on another site about how beneficial it was for
a 3X wheel to have the heads-in spoke go under the heads-out spoke at
the last crossing. It didn't sound altogether credible. but it got me
thinking - what good does the (lateral?) spoke crossing actually do?

I know from own experience that a wheel w/o this lateral cross may
generate vibrating sounds if the spoke tension isn't quite as it should,
but apart from that?

One casual analysis would give that you're preloading two flexible
elements against each other, which AFAIK rarely is seen as good
engineering.

Some further thought and you get the idea that maybe the lateral cross
does something good by sort-of compensating between the differences in
brace angle between outbound and inbound spoke. W/o the lateral cross
the outbound spoke would be anchored a full hub flange thickness further
out than the inbound. Assuming equal tension the lateral cross creates
virtual anchor points that's only a half spoke diameter away from
symmetry for both inbound and outbound spokes.

Then there's the question of torsion transfer interaction. If you have
a rear wheel laced with pulling spokes inbound then torque transfer
would reduce tension on the "pushing" spoke, causing the beneficial
offset created by the lateral cross to be reduced as well.

A rear laced pulling outbound OTOH would instead increase tension in
the "pushing" spoke during torque transfer conditions.

Ignoring the added complexites of torque transfer for awhile and simply
looking at a wheel that's merely rolling along when being subjected to a
sideways load, what happens then at the cross?
An inbound spoke passing through the load affected zone will lean
against the outbound spoke at the outermost cross, but is the local
sideways deflection of the rim sufficient for there to be any load
transfer/tension increase to the outbound spoke that cross on the
inside?
Or is it cross number dependent, with 1X, 2X offering too little
separation between loaded spoke and supporting spoke för there to be any
effect while 3X, 4X actually can offer some extra bracing?

Any thoughs?


--
dabac

[jim beam]

dabac wrote:
> Hi guys,
>
> Read some loose claims on another site about how beneficial it was for
> a 3X wheel to have the heads-in spoke go under the heads-out spoke at
> the last crossing. It didn't sound altogether credible. but it got me
> thinking - what good does the (lateral?) spoke crossing actually do?
>
> I know from own experience that a wheel w/o this lateral cross may
> generate vibrating sounds if the spoke tension isn't quite as it should,
> but apart from that?
>
> One casual analysis would give that you're preloading two flexible
> elements against each other, which AFAIK rarely is seen as good
> engineering.

indeed. but cyclists are nothing if not hidebound traditionalists, so
once a way is set, they'll stick with it. some will even fudge facts to
support preconception.


>
> Some further thought and you get the idea that maybe the lateral cross
> does something good by sort-of compensating between the differences in
> brace angle between outbound and inbound spoke. W/o the lateral cross
> the outbound spoke would be anchored a full hub flange thickness further
> out than the inbound. Assuming equal tension the lateral cross creates
> virtual anchor points that's only a half spoke diameter away from
> symmetry for both inbound and outbound spokes.
>
> Then there's the question of torsion transfer interaction. If you have
> a rear wheel laced with pulling spokes inbound then torque transfer
> would reduce tension on the "pushing" spoke, causing the beneficial
> offset created by the lateral cross to be reduced as well.
>
> A rear laced pulling outbound OTOH would instead increase tension in
> the "pushing" spoke during torque transfer conditions.
>
> Ignoring the added complexites of torque transfer for awhile and simply
> looking at a wheel that's merely rolling along when being subjected to a
> sideways load, what happens then at the cross?
> An inbound spoke passing through the load affected zone will lean
> against the outbound spoke at the outermost cross, but is the local
> sideways deflection of the rim sufficient for there to be any load
> transfer/tension increase to the outbound spoke that cross on the
> inside?
> Or is it cross number dependent, with 1X, 2X offering too little
> separation between loaded spoke and supporting spoke f�r there to be any
> effect while 3X, 4X actually can offer some extra bracing?
>
> Any thoughs?
>
>

it's probably as beneficial as tying and soldering. the explanation
jobst uses is that it "adds stability", iirc.

otoh, you can look at what modern engineering practices are among
pre-built wheel manufacturers - not many interleaved spokes there,
particularly those with research budgets like shimano, campy and mavic.

[datakoll]

http://www.jstor.org/pss/279210

[dabac]

datakoll Wrote:
> http://www.jstor.org/pss/279210
"Pattern Mathematics and Archaeology" and then a fuzzy pic of a
basket...

If this is meant to be funny in any way it's way too obscure for me.


--
dabac

[still just me]

On Thu, 24 Apr 2008 03:15:34 +1000, dabac
<dabac.38bytb@no-mx.forums.cyclingforums.com> wrote:

>datakoll Wrote:
>> http://www.jstor.org/pss/279210
>"Pattern Mathematics and Archaeology" and then a fuzzy pic of a
>basket...
>
>If this is meant to be funny in any way it's way too obscure for me.

You haven't hung around here long enough then...

[datakoll]

> You haven't hung around here long enough then...

some people call it maize

[datakoll]

Jobst Brandt tells us no advantage gained thru tieing spokes together.
This isnot building construction math. But JB stands by that.

Build your wheels without weaving and compare.

Think textiles, warp and woof, iron girder bridges, diagnol siding...

?

[dabac]

datakoll Wrote:
> Jobst Brandt tells us no advantage gained thru tieing spokes together.
I've read a post or two about tied and soldered, consider that subject
done and over with. What I'm asking about now is just the basic
outbound-under-inbound at the last cross.

datakoll Wrote:
> Build your wheels without weaving and compare.

I have, they were a bit noisy until I got the spoke tension sorted. Oh,
and wheel reflectors didn't stay put as well as they do otherwise.
I probably don't ride hard enough to generate any sharp insights, my
experiences seems to sum up rather nicely as: "well, that worked too"

Besides, wouldn't whatever I could see simply be considered
"anecdotal"?


--
dabac

[datakoll]

no itsnot anecdotal. It's your assembly. Itsnot like ura qualifying
for a journal or getting tenure (or not becasue of "it")

Even on a sports tourer with Conti TT, I find non-woven lacing mushy
compared to woven lacing: less sharpness at turn in over bumps,
slowness in changing direction ? Sinusodial rim wobbling?

[jim beam]

datakoll wrote:
>
> no itsnot anecdotal. It's your assembly. Itsnot like ura qualifying
> for a journal or getting tenure (or not becasue of "it")
>
> Even on a sports tourer with Conti TT, I find non-woven lacing mushy
> compared to woven lacing: less sharpness at turn in over bumps,
> slowness in changing direction ? Sinusodial rim wobbling?

so if that's the case, and it's only really friction between the two
spokes that could be having this effect, why would not locking the two
spokes with tying & soldering not have /more/ effect?

[datakoll]

On Apr 24, 11:56*pm, jim beam <spamvor...@bad.example.net> wrote:
> datakoll wrote:
>
> > no itsnot anecdotal. It's your assembly. Itsnot like ura qualifying
> > for a journal or getting tenure (or not becasue of "it")
>
> > Even on a sports tourer with Conti TT, I find non-woven lacing mushy
> > compared to woven lacing: less sharpness at turn in over bumps,
> > slowness in changing direction ? Sinusodial rim wobbling?
>
> so if that's the case, and it's only really friction between the two
> spokes that could be having this effect, why would not locking the two
> spokes with tying & soldering not have /more/ effect?

damned if I know. Althugh of the same class - fabricated structures
meant to support weight on planet Earth - obviously a bridge truss
and a framed wall are not a bicycle wheel. This insight plus the
odious nature of tieing spokes leads me to give Jobst the nod on this
one.

[datakoll]

On Apr 24, 11:56*pm, jim beam <spamvor...@bad.example.net> wrote:
> datakoll wrote:
>
> > no itsnot anecdotal. It's your assembly. Itsnot like ura qualifying
> > for a journal or getting tenure (or not becasue of "it")
>
> > Even on a sports tourer with Conti TT, I find non-woven lacing mushy
> > compared to woven lacing: less sharpness at turn in over bumps,
> > slowness in changing direction ? Sinusodial rim wobbling?
>
> so if that's the case, and it's only really friction between the two
> spokes that could be having this effect, why would not locking the two
> spokes with tying & soldering not have /more/ effect?

weaving the last crossing is more aerodynamic, less likely to trap
squirrels.
while the shorter spoke question is open but buried, comparison to
building engineering is unequal with curve bracing from the rim.
but 4x spokes are braced by the mate. Is "braced" an acceptable
engineering term ?
?