Sapim CX-Ray spoke question



R

RS

Guest
Will Sapim CX-Ray spokes have more side to side deflection then
Sapim Race (14/15) spokes? I know the CX-Ray are supposedly
stronger and lighter (and substantially more expensive) but I wonder if
there is any disadvantage to them. I'm about 190lb and will have a
set of wheels built up with DA7700 hubs fr: 28/2x rear-oc: 32/3x w/
Velocit Aerohead rims.

I ask because I notice the American Classic 350 Wheels have a weight
limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
though they use a radial lace front.
 

daveornee

New Member
Sep 18, 2003
2,763
0
0
RS said:
Will Sapim CX-Ray spokes have more side to side deflection then
Sapim Race (14/15) spokes? I know the CX-Ray are supposedly
stronger and lighter (and substantially more expensive) but I wonder if
there is any disadvantage to them. I'm about 190lb and will have a
set of wheels built up with DA7700 hubs fr: 28/2x rear-oc: 32/3x w/
Velocit Aerohead rims.

I ask because I notice the American Classic 350 Wheels have a weight
limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
though they use a radial lace front.
Yes, less lateral stiffness.
CX-Ray is processed from Sapim's Laser 14/17 DB spoke.
CX-Ray has longer fatique cycle life and is about the same weight as Laser spokes.
I expect longer fatique cycle life for the entire wheel built with CX-Ray, but about 10% less lateral stiffness... all other things being equal.
David Ornee, Western Springs, IL
 
J

jim beam

Guest
RS wrote:
> Will Sapim CX-Ray spokes have more side to side deflection then
> Sapim Race (14/15) spokes? I know the CX-Ray are supposedly
> stronger and lighter (and substantially more expensive) but I wonder if
> there is any disadvantage to them. I'm about 190lb and will have a
> set of wheels built up with DA7700 hubs fr: 28/2x rear-oc: 32/3x w/
> Velocit Aerohead rims.
>
> I ask because I notice the American Classic 350 Wheels have a weight
> limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
> though they use a radial lace front.
>

as dave says, there's less metal in the cross-section so they're more
elastic. more elastic means more lateral deflection. that's not so
much of an issue for the racing-snakes, but as you get bigger, it
becomes much more of a rideability factor.
 
is weight a problem? DT alpine III at 30% heavier are touted as
touring spokes from a positive enhanced torque rod elasticity or
lateral deflection. If I understand what is meant by lateral
deflection.
a touring load with an average rider should go 210-230lbs.
does the CX-Ray's lightness at -30% exclude the spoke from a touring
wheel application or would the CX combined with a double wall touring
rim give an increased suspension characteristic for touring over the
Alpines??
 
J

jim beam

Guest
[email protected] wrote:
> is weight a problem? DT alpine III at 30% heavier are touted as
> touring spokes from a positive enhanced torque rod elasticity or
> lateral deflection. If I understand what is meant by lateral
> deflection.


1. lateral deflection is how much the rim can move from side to side -
that's a function of bracing angle, rim stiffness and spoke elasticity.
other things being equal, spoke elasticity is a function of it's cross
section area.

2. alpine 3's are triple butted with the thickest end being for the
elbow section. iirc, that's 2.3/1.8/2.0. the 1.8 section is not going
to give you any appreciably better wind-up resistance [not to be
confused with lateral deflection] than a standard 2.0/1.8/2.0 spoke.

3. unless it's changed, the elbow shank on the alpine is also much
longer than standard spokes. this means that unless you have an
exceptionally thick hub flange, these spokes are going to have
substantial over-hang and imo, are going to be fatigue challenged due to
the resultant extra bending moment.

> a touring load with an average rider should go 210-230lbs.
> does the CX-Ray's lightness at -30% exclude the spoke from a touring
> wheel application or would the CX combined with a double wall touring
> rim give an increased suspension characteristic for touring over the
> Alpines??


fatigue benefits aside, i wouldn't use x-rays on a tourer. as a bigger
guy, i know what the extra elasticity of really skinny spokes feels
like, and for things like shimmy, a factor on loaded tourers, more
elasticity is a major "avoid" item. if you want to have the best
achievable fatigue resistance, spring the dough on a thick flanged phil
wood touring hub and the alpines. or buy wheels that use straight pull
spokes.
 
On Apr 23, 11:21 pm, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > beamer, that's exactly the opposite of contemporary thought

>
> so?


what you write is science fiction?
what the devil is lateral deflection? and with no diagram.
thin middle spokes increase the torque rod suspension characteristic
of bicycle wheels
that is engraved on a tablet at STANFORD
that's why DT makes DT ALPINE III touring spokes.
 
J

jim beam

Guest
[email protected] wrote:
> On Apr 23, 11:21 pm, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> beamer, that's exactly the opposite of contemporary thought

>> so?

>
> what you write is science fiction?


don't you mean science f_R_iction?

> what the devil is lateral deflection? and with no diagram.


http://www.sheldonbrown.com/rinard/wheel/index.htm

> thin middle spokes increase the torque rod suspension characteristic
> of bicycle wheels


no torque on a spoke outside of initial build. the rest of its life is
that of longitudinal elasticity.

> that is engraved on a tablet at STANFORD


not /at/ stanford. from some guy that tells you he /attended/ stanford.
at every possible opportunity. as if that somehow negates all his
mistakes.

what would his mistakes mean if he tried to stand on merit alone and
/didn't/ tell you he's attended stanford [at every possible opportunity]?

> that's why DT makes DT ALPINE III touring spokes.


yes, and in the right hub, they'll be fine. check into the shank length
question at dtswiss.com and decide for yourself. with a shank nearly
2mm longer than normal, they /really/ aren't for standard flange hubs.
 

daveornee

New Member
Sep 18, 2003
2,763
0
0
is weight a problem? DT alpine III at 30% heavier are touted as
touring spokes from a positive enhanced torque rod elasticity or
lateral deflection. If I understand what is meant by lateral
deflection.
a touring load with an average rider should go 210-230lbs.
does the CX-Ray's lightness at -30% exclude the spoke from a touring
wheel application or would the CX combined with a double wall touring
rim give an increased suspension characteristic for touring over the
Alpines??
Compromise in selecting wheel components seems to be very emotional for some. How stiff do you want the wheel to be?
What components are you willing to change to get that specified stiffness.
I demonstrated a 5% lateral stiffness difference in changing from 14 g to 14/15 DB spokes in an otherwise identical build. In that particular comparison the lateral deflection difference was .07 mm at a 25 pound lateral deflection load.
Since most of the length of the DT Alpine III is 1.8 mm (15 g) I would think the lateral stiffness difference between it and a 14 g (2.0 mm) spoke would be in the range of 5%. Now if you compare an Alpine III to a CX-Ray in the same wheel build, you would find the CX-Ray wheel to be another ~5% less in lateral stiffness.
You can gain lateral stiffness via a stiffer and taller flanged hub (and space the flanges as far apart as possible too).
You can also gain lateral stiffness via a stiffer rim. I have seen some double wall rims used for touring that are relatively flexible and some like the Alex Rims G6000 that are very stiff laterally (and radially).
The fatigue life of CX-Ray spokes makes them attractive to some, but the price and added flexibility make them out of the question for others.
The stiffest wheel I have built so far is with Wheelsmith DH 13/14 spokes on a high flange Phil Wood hub using 26" MTB 40H Velocity Deep V rim.
Damon Rinard measured lateral stiffness on 140 wheels and posted his findings at:
http://www.sheldonbrown.com/rinard/wheel/data.htm
I don't have the "Sleeping Beauty" sensitivity to feel the differences in lateral stiffness in the wheels I ride. I attribute any differences I feel to the tires, inflation amount, pavement, wind conditions, and what side of the bed I got up on that morning.
 
On Tue, 24 Apr 2007 14:28:03 +1000, daveornee
<[email protected]> wrote:

[snip]

>I don't have the "Sleeping Beauty" sensitivity to feel the differences
>in lateral stiffness in the wheels I ride. I attribute any differences
>I feel to the tires, inflation amount, pavement, wind conditions, and
>what side of the bed I got up on that morning.


Dear Dave,

I tend to agree with you that the tiny differences in actual lateral
rim movement are likely to be swamped by tires, inflation, pavement,
and wind.

I'd add the flexing of the fork, frame, and handlebar.

But I know that you know the right fairy tale. You know that you know
it. Everyone else knows that you know it.

Sleeping Beauty was so notoriously dead to the world and insensitive
that she didn't even wake up in one version of the story when the
prince crept into her bedroom and--

http://en.wikipedia.org/wiki/Sleeping_Beauty

Er, she didn't wake up when the prince crept into her bedroom and
kissed her, as Disney put it in the G-rated version.

You were thinking of Anderson's Princess and the pea under her
mattress, the epitome of sensitivity:

http://en.wikipedia.org/wiki/The_Princess_and_the_Pea

I love the Italian version, where the woman who is in pain from riding
a 172.5 mm crank with a winter-thickness sock--

Er, where the woman who is in pain from sleeping on a wrinkled sheet
loses to the woman whose foot is injured by a falling flower petal.

What the devil the prince thought that he would do for fun after he
married such an easily bruised woman is almost as much a mystery as
what such sensitive riders--

Er, never mind.

Cheers,

Carl Fogel
 
Q

Qui si parla Campagnolo

Guest
On Apr 23, 1:33 pm, RS <[email protected]> wrote:
> Will Sapim CX-Ray spokes have more side to side deflection then
> Sapim Race (14/15) spokes? I know the CX-Ray are supposedly
> stronger and lighter (and substantially more expensive) but I wonder if
> there is any disadvantage to them. I'm about 190lb and will have a
> set of wheels built up with DA7700 hubs fr: 28/2x rear-oc: 32/3x w/
> Velocit Aerohead rims.
>
> I ask because I notice the American Classic 350 Wheels have a weight
> limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
> though they use a radial lace front.


A suggestion. Use the 14/15 on the rear..much more long term
duability. You save a teeny biy of weight with CX-rays but the wheel
will not be as strong.
 
R

Ron Ruff

Guest
On Apr 23, 1:33 pm, RS <[email protected]> wrote:
> I ask because I notice the American Classic 350 Wheels have a weight
> limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
> though they use a radial lace front.


AC wheels are "flex challenged", because their rear flange spacing is
quite narrow. Some large riders have issues with this, and the lighter
CX-Rays will flex more. If you use a hub with wider flanges, it is
less of an issue.
 
R

Ron Ruff

Guest
On Apr 23, 10:28 pm, daveornee <[email protected]
mx.forums.cyclingforums.com> wrote:
> I demonstrated a 5% lateral stiffness difference in changing from 14 g
> to 14/15 DB spokes in an otherwise identical build. In that particular
> comparison the lateral deflection difference was .07 mm at a 25 pound
> lateral deflection load.


I'm curious about your test setup. Have you tested many wheels? I've
been trying to test a few, but my "rig" is not very stiff. On the
other hand I'm getting bigger differences than that. It seems to me
from calculations and experiments that most of the lateral stiffness
is provided by the spokes, and there is ~23% difference in stiffness
between those spokes (2.0 vs 1.8mm). Between 1.8mm and 1.5mm there is
~44% difference.
 
R

Ron Ruff

Guest
On Apr 23, 1:33 pm, RS <[email protected]> wrote:
> I ask because I notice the American Classic 350 Wheels have a weight
> limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
> though they use a radial lace front.


The AC hubs have a narrow flange spacing so they have less lateral
stability. Flange width is an important factor for determining lateral
stiffness. The DA 7700 hubs are much better in this respect.
 

daveornee

New Member
Sep 18, 2003
2,763
0
0
Ron Ruff said:
On Apr 23, 10:28 pm, daveornee <[email protected]
mx.forums.cyclingforums.com> wrote:
> I demonstrated a 5% lateral stiffness difference in changing from 14 g
> to 14/15 DB spokes in an otherwise identical build. In that particular
> comparison the lateral deflection difference was .07 mm at a 25 pound
> lateral deflection load.


I'm curious about your test setup. Have you tested many wheels? I've
been trying to test a few, but my "rig" is not very stiff. On the
other hand I'm getting bigger differences than that. It seems to me
from calculations and experiments that most of the lateral stiffness
is provided by the spokes, and there is ~23% difference in stiffness
between those spokes (2.0 vs 1.8mm). Between 1.8mm and 1.5mm there is
~44% difference.
When my uncle owned a machine shop I used his milling machine base + a couple of fixtures he milled for me to insure that the locknuts would not move when the wheel was laterally loaded. The setup was almost identical to Damon Rinard's setup when he had access to the machine shop at University of California - San Diego.
My fixtures were made from CrMo steel and I used a vinyl coated 1/8" steel cable looped over the rim to hold the 25 pound weight. I intended to test a bunch of wheels, but my time and shop time became obstacles.
Yes, the spokes themselves have a contribution to the lateral stiffness, but the rim, hub, and how the spokes are laced also contribute to how the wheel responds to lateral loading. I also had plans to see how various wheel configurations respond in radial loading.... and then in combination of radial and lateral loading. Again, my time and my uncle's patience/machine shop avaialbility became obstacles I could not overcome.
Check out what Damon says and measures on his site:
"7. How does spoke gauge affect stiffness?
Thicker spokes make a wheel stiffer, if all else is equal. A typical 32 spoke wheel built with 2.0mm spokes is about 11% stiffer than a similar wheel built with 2.0-1.45mm swaged spokes.

Compare the deflection of two wheels: numbers 39 and 47. Wheel 39 is built with 2.0-1.45mm swaged spokes, but wheel 47 is built with 2.0mm straight gauge spokes. Hub dimensions are effectively identical, spoke count is the same and the rims are the same make and model, so the only structural difference is the spoke gauge.
Result? The wheel with thinner spokes deflected 0.051" (1.30mm) in font and 0.067"1.70mm) in the rear, but the wheel with thicker spokes deflected less: only 0.046" (1.17mm) and 0.055" (1.40mm) for front and rear, respectively. That's an 11% increase in stiffness for the thicker spoked wheels.
Interestingly, wheel stiffness depends on more than just spoke thickness; the rim and other factors also contribute, so only part of the increase in raw spoke stiffness shows up in measured wheel stiffness. The thicker spoke by itself is nearly twice as stiff axially as the thinner spoke!"
From:
http://www.sheldonbrown.com/rinard/wheel/index.htm
Item #7
and data table at:
http://www.sheldonbrown.com/rinard/wheel/data.htm
I did a few tests by only changing one variable, such as spoke guage, to get the details of what goes on there. I varied hubs, such as changing from Shimano Ultegra to Phil Wood.... but I also had to use slightly shorter spokes with the PW hubs. My tests are old and my uncle has since sold his shop and retired to play golf.
David Ornee, Western Springs, IL
 
R

Ron Ruff

Guest
On Apr 23, 10:28 pm, daveornee <[email protected]
mx.forums.cyclingforums.com> wrote:
> I demonstrated a 5% lateral stiffness difference in changing from 14 g
> to 14/15 DB spokes in an otherwise identical build. In that particular
> comparison the lateral deflection difference was .07 mm at a 25 pound
> lateral deflection load.


I'm interested in more details about this. I've tested a few wheels,
but not with spoke gauge as the only variable. Also, my rig isn't very
stiff... but it seems like the spokes should have a greater effect
than that. In the FE model I made, spoke stiffness mattered more than
the rim stiffness.
 

daveornee

New Member
Sep 18, 2003
2,763
0
0
Ron Ruff said:
On Apr 23, 1:33 pm, RS <[email protected]> wrote:
> I ask because I notice the American Classic 350 Wheels have a weight
> limit of 220lb. with 14/15 spokes but only 180lb with Sapim CX-Ray,
> though they use a radial lace front.


AC wheels are "flex challenged", because their rear flange spacing is
quite narrow. Some large riders have issues with this, and the lighter
CX-Rays will flex more. If you use a hub with wider flanges, it is
less of an issue.
Low number of flexible spokes on closely spaced hub flanges is not a good combination. Once a spoke goes slack it isn't doing the job intended.
It is interesting to see the approaches of different manufacturers. Cane Creek used to make (and maybe still does make the Cane Creek Crono) a front wheel with 18 each 2.0 mm diameter spokes on a very widely spaced hub. That wheel had significant lateral stiffness, decent aero characteristics, reasonable bearing seal drag, and relatively low radial stiffness.
You can see other characteristics of 7 different wheels that François Grignon tested at:
http://www.sheldonbrown.com/rinard/wheel/grignon.htm
Where he shows the 18 spoke wheel having a little more lateral stiffness than a 32 spoke wheel (yes, I know it has 2.0/1.8 butted spokes), but only 2.2% less lateral stiffness than a 36 spoke wheel with 2.0 straight gague spokes.
David Ornee, Western Springs, IL
 

daveornee

New Member
Sep 18, 2003
2,763
0
0
Ron Ruff said:
On Apr 23, 10:28 pm, daveornee <[email protected]
mx.forums.cyclingforums.com> wrote:
> I demonstrated a 5% lateral stiffness difference in changing from 14 g
> to 14/15 DB spokes in an otherwise identical build. In that particular
> comparison the lateral deflection difference was .07 mm at a 25 pound
> lateral deflection load.


I'm interested in more details about this. I've tested a few wheels,
but not with spoke gauge as the only variable. Also, my rig isn't very
stiff... but it seems like the spokes should have a greater effect
than that. In the FE model I made, spoke stiffness mattered more than
the rim stiffness.
I built two identical wheels; one Sun CRT16-II 36 spoke front built 3-cross using DT 2.0 mm spokes and brass nipples on a 1993 Campagnolo Chorus hub... and the other Sun CRT16-II 36 spoke front built 3-cross using DT Competition 2.0/1.8 mm spokes and brass nipples on a 1993 Campagnolo Chorus hub.
I measured 1.45 mm lateral deflection at the 25 pound load with the straight 2.0 mm spoked wheel.
I measured 1.52 mm lateral deflection at the 25 pound load with the 2.0/1.8 mm spoked wheel.
I wonder how you come up with the data on rim stiffness to enter into your FE program.
David Ornee, Western Springs, IL
 
On 24 Apr 2007 12:47:48 -0700, Ron Ruff <[email protected]> wrote:

>On Apr 23, 10:28 pm, daveornee <[email protected]
>mx.forums.cyclingforums.com> wrote:
>> I demonstrated a 5% lateral stiffness difference in changing from 14 g
>> to 14/15 DB spokes in an otherwise identical build. In that particular
>> comparison the lateral deflection difference was .07 mm at a 25 pound
>> lateral deflection load.

>
>I'm interested in more details about this. I've tested a few wheels,
>but not with spoke gauge as the only variable. Also, my rig isn't very
>stiff... but it seems like the spokes should have a greater effect
>than that. In the FE model I made, spoke stiffness mattered more than
>the rim stiffness.


Dear Ron,

Dave may be getting the kind of precision needed to measure 0.07 mm
differences in lateral rim deflection with his 25-lb rig.

But the top of Damon Rinard's table mentions that his values are
"average lateral deflection +/- 0.05mm" for what sounds like the same
~25 lb weight hanging from a rim:

http://www.sheldonbrown.com/rinard/wheel/data.htm

Similarly, Damon Rinard's table for deflection in inches (not mm) for
1/4 turns looser shows deflection changing ~0.004 inches (~0.10 mm)
for the first few 1/4 turns looser:

http://www.sheldonbrown.com/rinard/wheel/index.htm

(Page down to Questions 1. Does stiffness vary with spoke tension?)

That suggests that very small tension changes can affect the very
small deflection.

Weirdly, Rinard's deflection _decreased_ according to the measurements
for the first eight 1/4 turns that the nipples were loosened.

Cheers,

Carl Fogel