2 Cross Wheels
Benjamin T. Wolz
for the spokes. I've been told they are a little stiffer, and of course,
a tad bit lighter. Can anybody add anything to this? I just want to
know what exactly I am doing.
Ben
--
** ** Benjamin T. Wolz
**** (512) 451-1178
** wol...@ccwf.cc.utexas.edu
** WORK: wo...@arlut.utexas.edu
WWW -> http://ccwf.cc.utexas.edu/~wolzbt/index.html
Jonathan Mote
fewer crosses you have, the higher the frequency the spokes will
break at (regardless of wether its rear/front or rim/disk
brakes).
Jonathan Mote,
London,
UK.
Jobst Brandt
> I'm no wheel guru, but there is a general consensus that the fewer
> crosses you have, the higher the frequency the spokes will break at
> (regardless of wether its rear/front or rim/disk brakes).
Even with your disclaimer you are not off the hook for repeating such
blatant lore. It may have occurred to you that such generalizations
don't hold up well, especially with the parenthesized inclusion.
Besides, where do you get this "overall general concensus of opinion"
hereafter known as a consensus?
It isn't true!
Jobst Brandt <jbr...@hpl.hp.com>
Alex Oliver
10033...@CompuServe.COM says...
True, a wheel with a two-cross lacing pattern will result in more stress on
each bend on the spoke. Also, on rear wheels, there is more "twist" at the
hub where the freewhell/cassette is with a two-cross whell.
However, there is a savings in weight with a two-cross pattern, and even
more with a radil lacing pattern. I personally would have no fears of
breaking spokes on a front wheel with 28 spokes and a two-cross pattern.
My rear wheel is radially laced on the left side and three-cross on the
right, and it's held up extremely well.
--
Catch y'all on the rebound,
--Alex
(har...@new-orleans.Neosoft.com)
Joel Gat
: However, there is a savings in weight with a two-cross pattern, and even
: breaking spokes on a front wheel with 28 spokes and a two-cross pattern.
Err weight savings? Jeez, if you have time and money to fix things, then
I guess a measly couple of grams is worth the extra effort. Personally,
I find it makes mmuch more sense to avoid saving a gram if it means
nothing will break - and hey, that IS important as unless you are Clark
Kent himself, if you break something - like a wheel - in a race, you
don't stand a chance at winning or even placing (lest you're in the front
and your break causes everyone behind you to crash and burn :)
Shortening your spokes by the little difference three to two cross makes
is not a safe weight savings. Go ahead and do it for other reasons by
all means. A good wheel builder can build a radial-spoked wheel that
will outlast just about any Made-in-Tiwan-by-machine three cross. So, if
you have the skill - or your local "pro" shop does - go ahead and build a
fewer-cross wheel for the lateral stiffness it offers if that's what you
want. If the wheel is done correctly, you will get the extra stiffness
that you want and AS A BONUS you get a weight savings. Don't use that as
a reason to go two-cross or even radial.
--
Joel Gat
jg...@ucdavis.ucdavis.edu
Jobst Brandt
> True, a wheel with a two-cross lacing pattern will result in more
> stress on each bend on the spoke. Also, on rear wheels, there is
> more "twist" at the hub where the freewhell/cassette is with a
> two-cross whell.
Would you care to explain where the "more stress" comes from and how
much more it is? What is the twist for x-3 in contrast to x-2 on a 32
spoke wheel, for instance? I'm curious where you get these "facts".
> However, there is a savings in weight with a two-cross pattern, and
> even more with a radil lacing pattern. I personally would have no
> fears of breaking spokes on a front wheel with 28 spokes and a
> two-cross pattern.
Hey! Wait a minute. First you imply it is not a good idea and then
you say it's OK. Meanwhile bike lore gets reinforced by repitition.
> My rear wheel is radially laced on the left side and three-cross on
> the right, and it's held up extremely well.
Jobst Brandt <jbr...@hpl.hp.com>
Alex Oliver
>Would you care to explain where the "more stress" comes from and how
>much more it is? What is the twist for x-3 in contrast to x-2 on a 32
>spoke wheel, for instance? I'm curious where you get these "facts".
It's fairly obvious, really. The mst stress on a single spoke is at the
bend, or j-hook, where the spoke attaches to the hub. On a radially-laced
wheel, all the stress on the spoke is at that one point. On a one-, two-,
or three-cross wheel, the stress is distributed along the spoke at points of
intersection with other spokes.
>Hey! Wait a minute. First you imply it is not a good idea and then
>you say it's OK. Meanwhile bike lore gets reinforced by repitition.
Wrong, I never implied it was a bad idea, I said it is not as strong as a
three-cross pattern due to increase in POSSIBLE failure of the spokes at the
bend. While this is a slight gamble, it's not one I'd be afraid to make. I
experiment with lacing patterns on my wheels all the time, and am quite
comfortable going against the standard 14 gauge, 32 spoke, three-cross
wheels you see on most bikes.
The only thing I haven't yet tried is a wheel with twisted spokes. Anyone
ever build one?
Jobst Brandt
> It's fairly obvious, really. The most stress on a single spoke is
> at the bend, or j-hook, where the spoke attaches to the hub. On a
> radially-laced wheel, all the stress on the spoke is at that one
> point. On a one-, two-, or three-cross wheel, the stress is
> distributed along the spoke at points of intersection with other
> spokes.
This may be fairly obvious to you but I don't see where you get this.
A properly stress relieved wheel has the greatest stress in the root
of the threads and in the slender part of a swaged spoke. But that
aside, a wheel that has not been stress relieved often has higher
stress in the elbow but how that stress is reduced by crossing other
spokes is not apparent. Maybe you can explain that.
>> Hey! Wait a minute. First you imply it is not a good idea and
>> then you say it's OK. Meanwhile bike lore gets reinforced by
>> repetition.
> Wrong, I never implied it was a bad idea, I said it is not as strong
> as a three-cross pattern due to increase in POSSIBLE failure of the
> spokes at the bend.
There you just said it again. "it is not as strong" What else do you
mean by this other than this is a weaker assembly and that average
intelligence can deduce that it is not a good idea to give up strength
on bicycle parts that are all designed near the light weight (low
strength) limit anyway.
> While this is a slight gamble, it's not one I'd be afraid to make.
> I experiment with lacing patterns on my wheels all the time, and am
> quite comfortable going against the standard 14 gauge, 32 spoke,
> three-cross wheels you see on most bikes.
Well, when are you going to discover the one that works? You must
have come up with some results, I assume.
> The only thing I haven't yet tried is a wheel with twisted spokes.
> Anyone ever build one?
Must you? That is something you should be able to analyze without
trying it. There are many things in life that you can forego if you
look at them critically. Not everything must be tried to prove it
dangerous or ineffectual.
Jobst Brandt <jbr...@hpl.hp.com>
Alex Oliver
>
>Alex Oliver writes:
>
Man, you certainly do enjoy these little banters, don't you? :)
>This may be fairly obvious to you but I don't see where you get this.
>A properly stress relieved wheel has the greatest stress in the root
>of the threads and in the slender part of a swaged spoke. But that
>aside, a wheel that has not been stress relieved often has higher
>stress in the elbow but how that stress is reduced by crossing other
>spokes is not apparent. Maybe you can explain that.
Look at a wheel laced in a cross pattern (any number will do) with
interlaced spokes. That is, there is one point where the two crossing
spokes change "position" -- one spoke will be under the other until a point
where it crosses above. Now, think of the lateral stress on a spoke and how
that changes when one spoke crosses another. The stress which would rest
completly on the hook of the spoke at the hub is now spread further
throughout the spoke, particularly at the interlaced cross.
As far as the most stress being at the threads and at the slender part of a
swaged spoke (which I completely disagree with), all I can say is this: Go
to your local bike shop, and ask a mechanic what the most common point on a
spoke where failure occurs is. I assure you they will say it is at the
bend.
>There you just said it again. "it is not as strong" What else do you
>mean by this other than this is a weaker assembly and that average
>intelligence can deduce that it is not a good idea to give up strength
>on bicycle parts that are all designed near the light weight (low
>strength) limit anyway.
What I'm suggesting is that the "light weight limit" defined by many bicycle
builders is, in fact, not the limit at all. Three cross, 32-spoke, 14g
spoked wheels are a safe bet for bicycle manufacturers, especially since so
many of the wheels on their bikes are made by barley-skilled laborers. I
guarantee if I build a two-cross wheel with 28 14/15g double-butted spokes,
it will be stronger than most stock wheels that come on bikes right out of
factories.
>> While this is a slight gamble, it's not one I'd be afraid to make.
>> I experiment with lacing patterns on my wheels all the time, and am
>> quite comfortable going against the standard 14 gauge, 32 spoke,
>> three-cross wheels you see on most bikes.
>
>Well, when are you going to discover the one that works? You must
>have come up with some results, I assume.
I have come up with many, as a matter of fact. On one front wheel, I use
Fiber Flight carbon fiber bladed spokes (32 hole, 3-cross). On another, I
use 32 14/15g double-butted spokes, laced radially. On another, I use 28
15g spokes laced 2-cross.
As I've mentioned before, my rear wheel is 32 hole with 14/15g double-butted
spokes. The left side is laced radially, and the right side is laced
3-cross.
I use alloy Wheelsmith nipples on all my wheels.
The only spoke failure I've had on any of these wheels is two broken carbon
fiber blades. However, this occurred after my bike flew through the air and
landed spokes first on a small tree stump. I suspect if I'd had steel
spokes in that incident, my wheel would have fared much worse than it did.
>> The only thing I haven't yet tried is a wheel with twisted spokes.
>> Anyone ever build one?
>
>Must you? That is something you should be able to analyze without
>trying it. There are many things in life that you can forego if you
>look at them critically. Not everything must be tried to prove it
>dangerous or ineffectual.
"Must I"? Of course not. Would I like to? Absolutely. I don't want to
look at one and analyze it, I've done that. I want to build one and see
what the advantages are in construction, then ride it and see what
advantages there are in performance.
And what if it is a tremendous advantage, and not "dangerous or
ineffectual"? I think we have an inherent difference in opinion of bicycle
technology. If you want to stick with what's been done for the past 40
years, feel free, but don't chastise others for wanting to experiment with
things that they find better than the present industry standards.
Jobst Brandt
> Man, you certainly do enjoy these little banters, don't you? :)
I suppose this is an inside joke to which I am not privy.
> Look at a wheel laced in a cross pattern (any number will do) with
> interlaced spokes. That is, there is one point where the two
> crossing spokes change "position" -- one spoke will be under the
> other until a point where it crosses above. Now, think of the
> lateral stress on a spoke and how that changes when one spoke
> crosses another. The stress which would rest completely on the hook
> of the spoke at the hub is now spread further throughout the spoke,
> particularly at the interlaced cross.
You may not be aware of this, but I have analyzed and measured these
forces and found interleaving spokes does not strengthen wheels. I
published this report a while ago and no contrary reports have
appeared. There is no evidence in what your statement to support the
contention that it it so, only that you state it is so. Have you
measured any these effects?
> As far as the most stress being at the threads and at the slender
> part of a swaged spoke (which I completely disagree with), all I can
> say is this: Go to your local bike shop, and ask a mechanic what the
> most common point on a spoke where failure occurs is. I assure you
> they will say it is at the bend.
If you consider that spokes are stressed in tension and that the cross
section is a minimum at the two point I mentioned, then these are by
definition the points of highest stress. That spokes break at the
elbow only proves that there are residual stresses from manufacture
and spoke insertion that were not adequately relieved by the wheel
builder.
>> There you just said it again. "it is not as strong" What else do you
>> mean by this other than this is a weaker assembly and that average
>> intelligence can deduce that it is not a good idea to give up strength
>> on bicycle parts that are all designed near the light weight (low
>> strength) limit anyway.
> What I'm suggesting is that the "light weight limit" defined by many
> bicycle builders is, in fact, not the limit at all. Three cross,
> 32-spoke, 14g spoked wheels are a safe bet for bicycle
> manufacturers, especially since so many of the wheels on their bikes
> are made by barley-skilled laborers. I guarantee if I build a
> two-cross wheel with 28 14/15g double-butted spokes, it will be
> stronger than most stock wheels that come on bikes right out of
> factories.
You're dodging and weaving. First you said it builds a weaker wheel and
then you said it doesn't affect the performance. You can't have it both
ways. That there is a safety margin in wheels is a constant for any
statistical group but cutting down on it is not a good idea.
>>> While this is a slight gamble, it's not one I'd be afraid to make.
>>> I experiment with lacing patterns on my wheels all the time, and am
>>> quite comfortable going against the standard 14 gauge, 32 spoke,
>>> three-cross wheels you see on most bikes.
>>
>> Well, when are you going to discover the one that works? You must
>> have come up with some results, I assume.
> I have come up with many, as a matter of fact. On one front wheel,
> I use Fiber Flight carbon fiber bladed spokes (32 hole, 3-cross).
> On another, I use 32 14/15g double-butted spokes, laced radially.
> On another, I use 28 15g spokes laced 2-cross.
Now you're getting down to the substance. I guess you didn't read
about all the failures that were reported here and by bike shops for
FiberFlight spokes that are as good as gone anyway. I also suppose
the list you present is not the whole story and that your
experimenting with unproven materials is continuing. Judging from the
"many", I guess you still haven't found what is good. I see this as
experimental work and not the sort of thing on which you should give
advice to others.
> As I've mentioned before, my rear wheel is 32 hole with 14/15g
> double-butted spokes. The left side is laced radially, and the
> right side is laced 3-cross.
You might wonder why, in the last 100 years, there have been few as
perceptive as you who switched to this spoke arrangement. You seem to
suggest that there are many technically backward people in the
business. I am not convinced, but if you are right, I see great
possibilities for a book that you could write on the subject in which
you could set the record straight.
> I use alloy Wheelsmith nipples on all my wheels.
You probably have no idea why brass remains the mainstay of spoke
nipples in the industry. There is a bit more margin with brass.
> The only spoke failure I've had on any of these wheels is two broken
> carbon fiber blades. However, this occurred after my bike flew
> through the air and landed spokes first on a small tree stump. I
> suspect if I'd had steel spokes in that incident, my wheel would
> have fared much worse than it did.
As long as you leave your technical evaluation to such speculation,
your credibility won't rise much. Others have had different experience
with carbon spokes and came to different conclusions.
>>> The only thing I haven't yet tried is a wheel with twisted spokes.
>>> Anyone ever build one?
>>
>> Must you? That is something you should be able to analyze without
>> trying it. There are many things in life that you can forego if you
>> look at them critically. Not everything must be tried to prove it
>> dangerous or ineffectual.
> "Must I"? Of course not. Would I like to? Absolutely. I don't
> want to look at one and analyze it, I've done that. I want to build
> one and see what the advantages are in construction, then ride it
> and see what advantages there are in performance.
Well I guess you must because your analytical abilities are wanting.
The weakness of that arrangement should be glaringly apparent from
cursory inspection as well as all the comments it has received here on
the net that should inspire you to consider these faults.
> And what if it is a tremendous advantage, and not "dangerous or
> ineffectual"? I think we have an inherent difference in opinion of
> bicycle technology. If you want to stick with what's been done for
> the past 40 years, feel free, but don't chastise others for wanting
> to experiment with things that they find better than the present
> industry standards.
That's a nice but unrealistic thought. You needn't be a sucker for
everything that comes along in order to prove that you are unbiased
and open minded. Taken further, that approach can ultimately prove
you to be empty minded. Snowflake spoking is not so complicated as to
defy thorough analysis by inspection. If you don't believe this, I
don't think a career in engineering is in your future although by your
posting I get the impression you believe so.
Jobst Brandt <jbr...@hpl.hp.com>
Paul B. Anders
wheel is much like Alex's, 32 spoke 2-cross drive side, radial non-drive.
But I have no problem admitting that I built it this way mainly for looks.
It works fine, but so would a 3-cross design on both sides. The weight savings
are miniscule, aero improvments very minimal or non-existant, and if I
break a spoke on the radial side, I have no crossings to retain the spoke
from flopping around and possibly jamming up the works. When this wheel
is replaced, I'm going back to a 3-cross design on both sides.
I've related this story before, but it bears repeating here. In the '93
Tour Cyclist Feminin (women's TdF), a friend of mine who is a very good US
cyclist was in the race. She was riding on a radial 28 spoke front, and a
fairly exotic 28 spoke rear wheel. She had an opportunity to examine the
eventual winner's bike (that of Leontine van Moorsel). At the time, Leontine
weighed about 110 lbs (down from 160 lbs a few years earlier!!). Her bike,
however, had not undergone such a weight reduction. She was riding a steel
Batavus, with 36-spoke, 14 ga, non-aero. Her bike weight about 25 lbs. And
it might be noted that Leontine dominated the race.
My point? Microscopic differences in performance between standard wheel
designs make almost no difference in competition, where physical and mental
differences dominate. For mass start races, whether you are on 3 cross, or
2-cross/radial, or whatever, don't expect that your wheel design will determine
your finish position. It won't.
BTW, when the Euro riders were questioned as to why they rode such heavy
wheels, they said that wheel strength was more important to them than a
tiny improvement in performance. A light wheel in a stage race provides
only a tiny advantage, but a wheel failure in a stage race might mean a loss
of several minutes. Not worth the risk in their eyes.
--
*******************************
* Brad Anders / Sunnyvale, CA *
* ban...@netcom.com *
*******************************
Robinson Kelly
cross. With no torsional stresses to deal with, well fewer, you can actually
build a pure radial lace front wheel. I have a Mavic 231 on an ultegra hub
on one of my mountain bikes with straight guage radial lace spokes (alloy
nipples) and have crashed hard enough to pull the tire off the rim, and the
rim stayed true. And this is as light as my soft as warm butter, 2 cross
double butted Mavic 230 front wheel which goes out of true when buffeted a
mild cross wind! (Both built by the same attention-to-detail wheel-building
pal of mine)
Enjoy.
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Eric Soroos
Anders) wrote:
> For mass start races, whether you are on 3 cross, or
>2-cross/radial, or whatever, don't expect that your wheel design will determine
>your finish position. It won't.
Unless it breaks. I have a friend who races and runs the best bike shop
in the area. His take on components: It's not fast if it breaks. Makes
sense to me.
>BTW, when the Euro riders were questioned as to why they rode such heavy
>wheels, they said that wheel strength was more important to them than a
>tiny improvement in performance. A light wheel in a stage race provides
>only a tiny advantage, but a wheel failure in a stage race might mean a loss
>of several minutes. Not worth the risk in their eyes.
eric
Adam M Bell
: Food for though on 2 cross. Try a radial lace pattern up front ie, zero
: cross. With no torsional stresses to deal with, well fewer, you can actually
: build a pure radial lace front wheel. I have a Mavic 231 on an ultegra hub
: on one of my mountain bikes with straight guage radial lace spokes (alloy
: nipples) and have crashed hard enough to pull the tire off the rim, and the
: rim stayed true. And this is as light as my soft as warm butter, 2 cross
: double butted Mavic 230 front wheel which goes out of true when buffeted a
: mild cross wind! (Both built by the same attention-to-detail wheel-building
: pal of mine)
Radial lacing my front wheel(s) has worked well for me too. I ran a 18 spoked
radial laced wheel for six months on my Mt Bike. Never had to true it.(Except
a few minor tweaks when I built it). I did however notice some flex in the wheel, during tight singletrack, but I tensioned it a bit more to correct the
problem. I recomend everyone to try a radial laced wheel at least once-
-Adam
Jobst Brandt
> Radial lacing my front wheel(s) has worked well for me too. I ran a
> 18 spoked radial laced wheel for six months on my Mt Bike. Never
> had to true it.(Except a few minor tweaks when I built it). I did
> however notice some flex in the wheel, during tight singletrack, but
> I tensioned it a bit more to correct the problem. I recomend
> everyone to try a radial laced wheel at least once.
You shouldn't present fiction as fact here, it's not healthy for your
credibility. If your spokes weren't so loose that they rattled, there
is no change in elasticity of wheel regardless of tension. For your
story to be true, the steel of the spokes would have to change its
elasticity with tension. This does not occur but is an old saw passed
on by bicycle magazine journalists. They write that low tension makes
a wheel more comfortable and shock absorbing. There is no truth to
this claim whatsoever and repeating it here in any form doen't cut it.
Jobst Brandt <jbr...@hpl.hp.com>
Wallace Wormley
: Adam Bell writes:
This: Jobst Brandt <jbr...@hpl.hp.com>
You are totally correct Jobst. Thats for setting the record straight.
Mike Fabian
> If your spokes weren't so loose that they rattled, there
> is no change in elasticity of wheel regardless of tension. For your
> story to be true, the steel of the spokes would have to change its
> elasticity with tension. This does not occur but is an old saw passed
> on by bicycle magazine journalists. They write that low tension makes
> a wheel more comfortable and shock absorbing. There is no truth to
> this claim whatsoever and repeating it here in any form doen't cut it.
I just saw these lies repeated one more time in an advertising
text for the Campagnolo Shamal wheels
(In the 1995 Bruegelmann mail order catalogue.)
The text claimed that the Shamal wheels (only 16 spokes)
have to times as much lateral stiffness when compared with
conventional wheels, because of the higher spoke tension.
The text also claimed that Shamal wheels are considerably lighter
than conventinal wheels, which is probably another lie.
(They did not dare to print the weight of a Shamal wheel in
the catalogue.).
Mike
--
Mike Fabian fab...@apollo.ph1.uni-koeln.de
Universitaet zu Koeln, I. Physikalisches Institut
Zuelpicher Str. 77, 50937 Koeln, Germany