Pulling/trailing spokes run along inside or outside of flange?



Hello,

When building wheels I've use the lacing method which runs the
pulling/trailing spokes along the inside of the hub flange. A few of
the much more experienced mechanics at the shop I have told me that
this is the wrong, but I am unsatisfied with their explainations.

I double-checked The Bicycle Wheel and Sheldon Brown's site and found
that both lacing instructions result in a wheel with pulling spokes
running along the inside of the flange. Sheldon Brown cites a few
reasons for this orientation--
http://www.sheldonbrown.com/wheelbuild.html#side

The only explaination provided by my co-workers that resembled sense
was that when the pulling spokes run along the outside of the flange
the flange spacing is effectively wider, making the pulling spokes
stronger. It is my understanding that a wider flange spacing makes a
wheel laterally and radially stronger, but that it doesn't increase
torque transmission to the rim. In fact, it seems to me that it would
decrease (however slightly) the pulling spokes ability to "pull".

Can anyone explain what, if any, effect on torque would be produced by
running the pulling spokes along the inside vs. outside of the flange?
The people telling me to run them along the outside have about a decade
more wrench experience than I, so I need to properly explain why they
should be run along the inside of the flange if I am going to continue
to do so at the shop.

Thanks, and Merry Christmas,
Anthony King
 
Anthony King writes:

> When building wheels I've use the lacing method which runs the
> pulling/trailing spokes along the inside of the hub flange. A few
> of the much more experienced mechanics at the shop I have told me
> that this is the wrong, but I am unsatisfied with their
> explanations.


> I double-checked The Bicycle Wheel and Sheldon Brown's site and
> found that both lacing instructions result in a wheel with pulling
> spokes running along the inside of the flange. Sheldon Brown cites
> a few reasons for this orientation--


http://www.sheldonbrown.com/wheelbuild.html#side

> The only explanation provided by my co-workers that resembled sense
> was that when the pulling spokes run along the outside of the flange
> the flange spacing is effectively wider, making the pulling spokes
> stronger. It is my understanding that a wider flange spacing makes
> a wheel laterally and radially stronger, but that it doesn't
> increase torque transmission to the rim. In fact, it seems to me
> that it would decrease (however slightly) the pulling spokes ability
> to "pull".


Well that doesn't hold water if you interleave spokes, because when
interlaced, they take an average approach angle that bisects the flange
width. Besides, how much do these folks believe the angular difference
is?

> Can anyone explain what, if any, effect on torque would be produced
> by running the pulling spokes along the inside vs. outside of the
> flange? The people telling me to run them along the outside have
> about a decade more wrench experience than I, so I need to properly
> explain why they should be run along the inside of the flange if I
> am going to continue to do so at the shop.


You seem to have "the Bicycle Wheel" at hand and it shows how small
torque loads on spokes are. Remember that all external loads shown
are the same, so the torque load is the same as the vertical load on
the wheel for easy comparison.

Jobst Brandt
 
M

Mark Janeba

Guest
[email protected] wrote:
> Hello,
>
> When building wheels I've use the lacing method which runs the
> pulling/trailing spokes along the inside of the hub flange. A few of
> the much more experienced mechanics at the shop I have told me that
> this is the wrong, but I am unsatisfied with their explainations.
>
> I double-checked The Bicycle Wheel and Sheldon Brown's site and found
> that both lacing instructions result in a wheel with pulling spokes
> running along the inside of the flange. Sheldon Brown cites a few
> reasons for this orientation--
> http://www.sheldonbrown.com/wheelbuild.html#side


Sheldon's reason #2 makes a LOT of sense, and it's the only reason I
need when building wheels. ("If the chain should overshoot the inner
sprocket due to the derailer being mis-adjusted or bent, it is likely to
get more seriously jammed between the spokes and the freewheel if the
spokes slant so as to wedge the chain inward under load.")

I suspect all *other* advantages of one side over the other are
negligible for most of us most of the time.

I assume most of us will drop the chain between the cogs and spokes
rarely if ever, but doing it just once will persuade you. It can be a
bear pulling the chain out of there when the spokes are angled to wedge
it in; what's worse, I think the spokes get "chewed" more in this situation.

Mark "Been there, done that" Janeba

(and a happy holiday to all)
 
A

A Muzi

Guest
[email protected] wrote:
> Hello,
>
> When building wheels I've use the lacing method which runs the
> pulling/trailing spokes along the inside of the hub flange. A few of
> the much more experienced mechanics at the shop I have told me that
> this is the wrong, but I am unsatisfied with their explainations.
>
> I double-checked The Bicycle Wheel and Sheldon Brown's site and found
> that both lacing instructions result in a wheel with pulling spokes
> running along the inside of the flange. Sheldon Brown cites a few
> reasons for this orientation--
> http://www.sheldonbrown.com/wheelbuild.html#side
>
> The only explaination provided by my co-workers that resembled sense
> was that when the pulling spokes run along the outside of the flange
> the flange spacing is effectively wider, making the pulling spokes
> stronger. It is my understanding that a wider flange spacing makes a
> wheel laterally and radially stronger, but that it doesn't increase
> torque transmission to the rim. In fact, it seems to me that it would
> decrease (however slightly) the pulling spokes ability to "pull".
>
> Can anyone explain what, if any, effect on torque would be produced by
> running the pulling spokes along the inside vs. outside of the flange?
> The people telling me to run them along the outside have about a decade
> more wrench experience than I, so I need to properly explain why they
> should be run along the inside of the flange if I am going to continue
> to do so at the shop.


Even people who are picky about nits ( me) admit this can be
argued either way.

With 'pulling' spokes on the inside there is less lash under
extreme side loads - the spoke can't straighten much if it
is already straight. OTOH, building in the inverse means an
errant rear changer will be less likely to mate with a
spoke. Neither scenario is common and the effect in each
case is minimal, so it doesn't matter.

I build 'pulling' spokes inside but I don't believe the
other way is wrong.

Now if you want to split hairs, I build fronts such that
left side innies go clockwise and right side innies go
counterclockwise. You'll get an argument from other
builders that a front ought to be built like a rear instead.
( all innies going the same way)

It truly doesn't make any difference I can see. The
discussion is only a shade past rim label/hub label
position and all that drivel.


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

Werehatrack

Guest
On 25 Dec 2005 12:43:54 -0800, "[email protected]"
<[email protected]> wrote:

>Hello,
>
>When building wheels I've use the lacing method which runs the
>pulling/trailing spokes along the inside of the hub flange. A few of
>the much more experienced mechanics at the shop I have told me that
>this is the wrong, but I am unsatisfied with their explainations.


Properly, IMO.

>I double-checked The Bicycle Wheel and Sheldon Brown's site and found
>that both lacing instructions result in a wheel with pulling spokes
>running along the inside of the flange. Sheldon Brown cites a few
>reasons for this orientation--
>http://www.sheldonbrown.com/wheelbuild.html#side
>
>The only explaination provided by my co-workers that resembled sense
>was that when the pulling spokes run along the outside of the flange
>the flange spacing is effectively wider, making the pulling spokes
>stronger. It is my understanding that a wider flange spacing makes a
>wheel laterally and radially stronger, but that it doesn't increase
>torque transmission to the rim. In fact, it seems to me that it would
>decrease (however slightly) the pulling spokes ability to "pull".


If this angle mattered at all, which I can't say whether it does, the
cross pattern would have more to do with it than the lateral angle,
since the degree to which the spoke is approaching the hub flange
tangentially would seem to be the important consideration.

Still, there's nothing to support any contention that the trailing
spokes should be head-in as far as I can see. Running the trailing
spokes head-out (as you do, and as is recommended elsewhere as you
discovered) puts slightly less lateral stress on the flange under
acceleration, however, so that's the way I would arrange them...and
from what I just saw on the bikes in the stable, somebody must agree
with that policy even if they have different reasons for doing so.

>Can anyone explain what, if any, effect on torque would be produced by
>running the pulling spokes along the inside vs. outside of the flange?
>The people telling me to run them along the outside have about a decade
>more wrench experience than I, so I need to properly explain why they
>should be run along the inside of the flange if I am going to continue
>to do so at the shop.


My advice in this circumstance: Lace *your* wheels the way *you*
prefer, and lace the *shop's* wheels the way that the shop management
is paying you to, if they have a policy about it, unless explicitly
instructed to do otherwise by a wheel's owner.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
W

Werehatrack

Guest
On 25 Dec 2005 12:43:54 -0800, "[email protected]"
<[email protected]> wrote:

>Hello,
>
>When building wheels I've use the lacing method which runs the
>pulling/trailing spokes along the inside of the hub flange. A few of
>the much more experienced mechanics at the shop I have told me that
>this is the wrong, but I am unsatisfied with their explainations.


Properly, IMO.

>I double-checked The Bicycle Wheel and Sheldon Brown's site and found
>that both lacing instructions result in a wheel with pulling spokes
>running along the inside of the flange. Sheldon Brown cites a few
>reasons for this orientation--
>http://www.sheldonbrown.com/wheelbuild.html#side
>
>The only explaination provided by my co-workers that resembled sense
>was that when the pulling spokes run along the outside of the flange
>the flange spacing is effectively wider, making the pulling spokes
>stronger. It is my understanding that a wider flange spacing makes a
>wheel laterally and radially stronger, but that it doesn't increase
>torque transmission to the rim. In fact, it seems to me that it would
>decrease (however slightly) the pulling spokes ability to "pull".


If this angle matters at all, the cross pattern has far more to do
with it than the lateral angle, since the degree to which the spoke is
approaching the hub flange tangentially is the important
consideration. The only difference head-in vs head-out appears to
make in that area is in the angle that the load is applied to the
flange in the lateral direction, and that's not at the same level of
importance as the tangentiality. Radial lacing places the load across
the smallest cross-section of the flange, cross lacing angles it so
that there's more flange material bearing the load. Head-in vs
head-out won't make a difference in that, so the loading argument
doesn't apply in the same manner in the in/out discussion. Looking at
the real difference, the lateral angular change between head-in and
head-out is so slight, and the acceleration vectors are so small in
that regard that the lateral force generated by the very slight
angular difference between head-in and head-out isn't enough to be
critical.

The observations elswhere about the potential for chain jam
escalation, which is a real-world issue that is easy to see, look like
the real trumps in this discussion.

In total, there's nothing persuasive to support any contention that
the trailing spokes should be head-in as far as I can see. Running
the trailing spokes head-out (as you and I do, and as is recommended
elsewhere as you discovered) may put very slightly less lateral stress
on the flange under acceleration, but even that's not an important
consideration by comparison to others...though it still supports
head-out for the trailing spokes, not head-in, in my opinion.

Whatever the rationale that is driving it, from a quick survey of the
bikes in the stable, it appears that the majority opinion favors the
trailing-head-out approach, as not one of the wheels here is built
with the trailing spokes head-in on the rear.

>Can anyone explain what, if any, effect on torque would be produced by
>running the pulling spokes along the inside vs. outside of the flange?


There isn't any difference in torque transmission from the hub to the
rim. The microscopic difference in lateral loading of the hub flange
(if measurable) will have no effect.

>The people telling me to run them along the outside have about a decade
>more wrench experience than I, so I need to properly explain why they
>should be run along the inside of the flange if I am going to continue
>to do so at the shop.


My advice in this circumstance: Lace *your* wheels the way *you*
prefer, and lace the *shop's* wheels the way that the shop management
is paying you to, if they have a policy about it, unless explicitly
instructed to do otherwise by a wheel's owner.

Much of the real world operates on superstition rather than knowledge;
where it matters, when you can differentiate the two, it's worth
standing up for the knowledge-driven viewpoint in my opinion. Where
it doesn't matter, and in particular where it's somebody else's
reputation that will suffer for the choice, the decision about whether
to remain silent or to try to educate the misinformed is one that must
be made by the person on the spot. I believe that your dilemma falls
into this category. Do as you feel the situation merits.


--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
Q

Qui si parla Campagnolo

Guest
[email protected] wrote:
> Hello,
>
> When building wheels I've use the lacing method which runs the
> pulling/trailing spokes along the inside of the hub flange. A few of
> the much more experienced mechanics at the shop I have told me that
> this is the wrong, but I am unsatisfied with their explainations.


Not 'wrong', in practice, it just doesn't matter.
>
> I double-checked The Bicycle Wheel and Sheldon Brown's site and found
> that both lacing instructions result in a wheel with pulling spokes
> running along the inside of the flange. Sheldon Brown cites a few
> reasons for this orientation--
> http://www.sheldonbrown.com/wheelbuild.html#side
>
> The only explaination provided by my co-workers that resembled sense
> was that when the pulling spokes run along the outside of the flange
> the flange spacing is effectively wider, making the pulling spokes
> stronger. It is my understanding that a wider flange spacing makes a
> wheel laterally and radially stronger, but that it doesn't increase
> torque transmission to the rim. In fact, it seems to me that it would
> decrease (however slightly) the pulling spokes ability to "pull".
>
> Can anyone explain what, if any, effect on torque would be produced by
> running the pulling spokes along the inside vs. outside of the flange?
> The people telling me to run them along the outside have about a decade
> more wrench experience than I, so I need to properly explain why they
> should be run along the inside of the flange if I am going to continue
> to do so at the shop.
>
> Thanks, and Merry Christmas,
> Anthony King
 
M

Mike Yankee

Guest
>Sheldon's reason #2 makes a LOT of sense, and it's the only reason I need when building wheels. ("If the chain should overshoot the inner sprocket...

Couldn't agree more, and I always lace my wheels that way. Here's a
"true" story about wrong-way wheels, though: Two years ago I removed
the original, shop-built rear wheel of my Merckx, which had remained
absolutely true for 25,000+ miles without ever having to be touched, to
put it on a "new" beater/rainbike I was building built up. Only then
did I notice -- you guessed it -- the super-true rear had been laced
the "wrong" way! Even now, with almost 28,000 miles on it, it's still
as true as the day it was built, far and away the truest wheel I've
ever owned.
 
W

Werehatrack

Guest
On 26 Dec 2005 06:46:51 -0800, "Mike Yankee" <[email protected]>
wrote:

>>Sheldon's reason #2 makes a LOT of sense, and it's the only reason I need when building wheels. ("If the chain should overshoot the inner sprocket...

>
>Couldn't agree more, and I always lace my wheels that way. Here's a
>"true" story about wrong-way wheels, though: Two years ago I removed
>the original, shop-built rear wheel of my Merckx, which had remained
>absolutely true for 25,000+ miles without ever having to be touched, to
>put it on a "new" beater/rainbike I was building built up. Only then
>did I notice -- you guessed it -- the super-true rear had been laced
>the "wrong" way! Even now, with almost 28,000 miles on it, it's still
>as true as the day it was built, far and away the truest wheel I've
>ever owned.


But I'd bet that lacing it the other way would have been just as
effective in producing that result.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
 
R

Ron Ruff

Guest
Mike Yankee wrote:
> Even now, with almost 28,000 miles on it, it's still
> as true as the day it was built, far and away the truest wheel I've
> ever owned.


Any particulars about your nice wheel... spokes, #, rim?