Completely Straight Spokes vs. Standard Spokes
JOSEPHA DEFILIPPIS
Pulstar) that are utilizing completely straight spokes (no bends at all) as
opposed to the standard spokes? I saw an ad for a Fuji bike with this
set-up.
Are the wheels significantly stronger? If so, why haven't other hub
and bike manufacturers incorporated this design? It seems the way the
Pulstar hubs are designed, cracked flanges will be extremely rare.
Thanks in advance.
Joey
Jobst Brandt
> Are the wheels significantly stronger? If so, why haven't other hub
> and bike manufacturers incorporated this design? It seems the way the
> Pulstar hubs are designed, cracked flanges will be extremely rare.
I see no benefit here and besides, there is a bicycle with an all
steel "Pulstar" hub built in 1900 or there abouts in the Wheelsmith
antique collection. This is old stuff and it didn't work then either.
The elbow protects the spoke head from taking the load straight on.
The head is the most poorly formed part of the spoke and is a typical
failure point as it is. Straight spokes only worsen the situation.
Jobst Brandt <jbr...@hpl.hp.com>
Kristan Roberge
>
> My only related experience is with my old Hercules seven speed motorcycle,
> which also had straight pull spokes in the rear wheel. That wheel, the
> whole bike, actually, was damn near indestructible.
>
I can only see one glaring flaw in the above statement. And that is that
the spokes on a motorcycle wheel tend to be alot shorter (and alot more
numerous) than on a bike wheel. Also Motorcycles typically use spokes in
the 13 gauge or thicker NOT 14 to 15/17 gauge like you'll see on a
mountain bike. They have enough extra material in their spokes (spreading the
load over more, shorter spokes too) that they don't have to worry about road shock
overstressing the spokes.
ron g macdonald
>I see no benefit here and besides, there is a bicycle with an all
>steel "Pulstar" hub built in 1900 or there abouts in the Wheelsmith
>antique collection. This is old stuff and it didn't work then either.
>The elbow protects the spoke head from taking the load straight on.
>The head is the most poorly formed part of the spoke and is a typical
>failure point as it is. Straight spokes only worsen the situation.
Jobst -- you're the authority here, and I wouldn't presume to argue, but
I'd like to know how can you tell that the failure occured at the head and
not at the bend. It seems to me that there is very little spatial
difference here and a fracture seemingly at the head could easily have
originated elsewhere.
My only related experience is with my old Hercules seven speed motorcycle,
which also had straight pull spokes in the rear wheel. That wheel, the
whole bike, actually, was damn near indestructible.
Does bending a spoke incur no structural penalty? Does post-failure
magnafluxing tell where the fracture originated, or does some other
evidence tell you the head is the culprit?
Ron MacDonald
r...@world.std.com
Scott McClellan
: Josepha deFilippis writes:
: Jobst Brandt <jbr...@hpl.hp.com>
Jobst,
I no longer have it, but I remember clearly that you said in response
to an earlier thread that the "...most common failure point was the elbow
or bend..." That is not a direct quote because I don't have the posting
anymore. This is confusing. Is the elbow the weak point, or is the spoke
head the problem? If both, what is the relative strength of each?
I recently purchased a CronoMetro wheel. It also uses straight pull spokes.
I like the design of the wheel it makes sense to me. One of the features
I liked was the straight pull spokes (although I acutally didn't like the
idea of all the force being applied to the head of the spoke). On the
CronoMetro wheel, the nipples are in the center of the wheel (the hub has a
large flange and the nipples are inside that flange). They claim that this
moves some of the moving mass toward the center of the wheel. This seems
to be a good idea (it may not make much difference but every little bit
helps). As a result, the spoke head is pulling against the rim (the rims
are custom drilled). The holes in the rim are 2mm and the spoke is pushed
through the hole, the nipple tightens on the other end of the spoke pulling
against the flange of the hub.
Have you seen the wheel? Are you familiar with the design? I could fax
you a picture. What do you think? Anybody else have any opinions or
experience with this wheel?
ron g macdonald
>I can only see one glaring flaw in the above statement. And that is that
>the spokes on a motorcycle wheel tend to be alot shorter (and alot more
>numerous) than on a bike wheel. Also Motorcycles typically use spokes in
>the 13 gauge or thicker NOT 14 to 15/17 gauge like you'll see on a
>mountain bike. They have enough extra material in their spokes (spreading the
>load over more, shorter spokes too) that they don't have to worry about road shock
>overstressing the spokes.
Most of what you say is true.
Can't remember the spoke count, but I doubt there were more than on a
bicycle. The spokes are shorter and stronger but, of course, they are
subjected to far more stress than on a bicycle. The motorcycle itself
weighed more than me and my bicycle put together, and had just a little
more horsepower than I do. :-)
I guess this is an apples and oranges comparison, but think the concept is
similar in both cases despite the difference in the application.
Ron MacDonald
r...@world.std.com
Jobst Brandt
>> I see no benefit here and besides, there is a bicycle with an all
>> steel "Pulstar" hub built in 1900 or there abouts in the Wheelsmith
>> antique collection. This is old stuff and it didn't work then either.
>> The elbow protects the spoke head from taking the load straight on.
>> The head is the most poorly formed part of the spoke and is a typical
>> failure point as it is. Straight spokes only worsen the situation.
> I'd like to know how can you tell that the failure occurred at the
> head and not at the bend. It seems to me that there is very little
> spatial difference here and a fracture seemingly at the head could
> easily have originated elsewhere.
When a head pops off it is exactly the head and nothing more. In fact,
sometimes they fail in the cone of the head. On elbowed spokes, this
is a tension failure that is caused by a lower stress than is present
at the elbow where failures usually occur in the bend. The failure in
the bend results from residual stress of manufacture and poor spoke
alignment (failure to stress relieve). The failure at the head can be
from poor seating with the head supported on one point only or a
poorly formed head. Robergel spokes, the ones that were generally
used before DT and WS came to the rescue, all began to pop heads as
the company went broke and their tooling began to wear out.
> My only related experience is with my old Hercules seven speed motorcycle,
> which also had straight pull spokes in the rear wheel. That wheel, the
> whole bike, actually, was damn near indestructible.
I think M/C spokes are generally not nearly as close to the limit as
bicycle spokes where every gram of weight is scrutinized.
> Does bending a spoke incur no structural penalty? Does post-failure
> magnafluxing tell where the fracture originated, or does some other
> evidence tell you the head is the culprit?
Spoke steel is, from my observation, a highly specialized material
because it must have high tensile strength, high ductility, and be
stainless and good at cold working. These characteristics conflict in
several respects. High tensile strength and ductility as well as
being stainless and workable, both conflict. However, the best spokes
today have these characteristics and as the tensile tests in "the
Bicycle Wheel" show, ductility of DT swaged spokes is enormous.
These spokes can be formed, entirely cold, without much loss in
integrity. However, the forming process flows (yields) the material
substantially and leaves fairly high residual stresses that can be
removed effectively only in the completed wheel. If this is not done,
these expensive spokes of exotic material will be performing similarly
high performance wheels with half inflated tires. You are asking for
failure.
Jobst Brandt <jbr...@hpl.hp.com>
Jobst Brandt
> I no longer have it, but I remember clearly that you said in
> response to an earlier thread that the "...most common failure point
> was the elbow or bend..." [...] This is confusing. Is the elbow the
> weak point, or is the spoke head the problem? If both, what is the
> relative strength of each?
As I pointed out in a previous response, the head, depending on the
way it formed, can be the weakest point because it is mashed onto the
end of this highly longitudinally oriented steel of the wire. The
elbow is only a weak point because it is in bending rather than pure
tension. It is the wheel builder's job to stress relieve the spokes
so that they are in pure tension, or nearly so. In a well built wheel
the elbow is no longer more vulnerable than the rest of the spoke,
especially if it is a swaged spoke.
> On the CronoMetro wheel, the nipples are in the center of the wheel
> (the hub has a large flange and the nipples are inside that flange).
> They claim that this moves some of the moving mass toward the center
> of the wheel.
This is not new. It was tried, as almost everything you can imagine,
at the turn of the century when the most talented and innovative people
focussed on the bicycle. This and the Pulstar hub did not survive for
the complexity and lack of redeeming merit.
> This seems to be a good idea (it may not make much difference but
> every little bit helps). As a result, the spoke head is pulling
> against the rim (the rims are custom drilled). The holes in the rim
> are 2mm and the spoke is pushed through the hole, the nipple
> tightens on the other end of the spoke pulling against the flange of
> the hub.
This amounts to so much theoretical qualitative conjecture that when
put into numbers will scare away almost any reasonable manufacturer
and wheel builder.
> Have you seen the wheel? Are you familiar with the design? I could
> FAX you a picture. What do you think?
That's OK. Although I haven't seen this one, I've seen its ancient
predecessors and I think I've seen enough. Have you seen the BMW M/C
wheel in which the spokes are straight and similarly have the nipples
in the hub? The spokes cross from the hub to the opposite rim horn
(the curled lip of the rim) so that the spoke is outside the tire.
This allows using tubeless tires, builds a strange looking wheel and
costs a pile. The lateral spoke angle is huge but then I haven't seen
many laterally collapsed M/C wheels lately.
Jobst Brandt <jbr...@hpl.hp.com>
Blake A Storey
I have a Pulstar front wheel and I have also built several sets of Pulstar
wheels for a Solar Car. They are by far the strongest wheels I have ever seen.
The Straight spokes allow a higher tension and eliminating the bend lessens the
chance of breakage at the head. Eliminating the J-bend is a tremendous
improvement and if anyone has problems with conventional wheels I suggest you
try these.
Blake A. Storey
-------------------------------------------------------------------------------
The Ohio State University Sunrayce Team
e-mail:stor...@osu.edu -Vehicle Dynamics
Blake A. Storey
>stronger or as strong as other wheels of otherwise identical parts?
>How do you know that the spokes are tighter than those of other wheels
>using similar rims? Please furnish more information on how all this
>is achieved. It sounds so much like the advertising brochure from
>Pulstar. Being a user you may be able to substantiate some of these
>Pulstar claims. I did not find any quantitative descriptions in their
>claims. Maybe you can fill us in about them.
>Jobst Brandt <jbr...@hpl.hp.com>
The wheels for the solar car in question were built essentially the same. I
built both with Sun Rhyno rims (20" BMX style) custom drilled for 32 spokes.
The spokes used were Wheelsmith of similar length and a cross 3 pattern was
used. What was varied was the hub. The first one was built with a standard
aluminum wheelchair hub and the bent spokes. The second was built with a
Pulstar wheelchair hub and straight pull spokes.
Testing was preformed on a 750lb 3-wheeled prototype vehicle travelling at
speeds of 30+mph. The wheels in question were the two front wheels. I had
several broken spokes on the standard hub while the Pulstar hub had no
breakage in the same test situation. It is for this reason that I feel the
Pulstar straight pull design to be superior.
While I don't have accurate readings of the tension on the spokes I do know
that I was able to put a lot more on the straight pull spokes. When I
attempted to put large amounts of tension on the bent spokes the bends gave
way and broke. I as well as another qualified builder I am working with have
had the same experience.
Any more questions?
Blake A. Storey
Joshua Putnam
Blake A Storey <bst...@magnus.acs.ohio-state.edu> wrote:
>Hello,
> I have a Pulstar front wheel and I have also built several sets of Pulstar
>wheels for a Solar Car. They are by far the strongest wheels I have ever seen.
>The Straight spokes allow a higher tension
Just curious how this works -- the limit of tension on a standard
spoked wheel is set by the rim strength, not the spoke, so it
seems hard to believe that any change in the spoke would allow a
higher tension in actual use.
--
Joshua Putnam
jpu...@eskimo.com
P.O. Box 13220 / Burton, WA 98013-0220
Jobst Brandt
> I have a Pulstar front wheel and I have also built several sets of
> Pulstar wheels for a Solar Car. They are by far the strongest
> wheels I have ever seen. The Straight spokes allow a higher tension
> and eliminating the bend lessens the chance of breakage at the head.
> Eliminating the J-bend is a tremendous improvement and if anyone has
> problems with conventional wheels I suggest you try these.
That's interesting. How did you determine that these wheels are
Scott McClellan
: Scott McClellan writes:
[much deleto]
: > On the CronoMetro wheel, the nipples are in the center of the wheel
: > (the hub has a large flange and the nipples are inside that flange).
: > They claim that this moves some of the moving mass toward the center
: > of the wheel.
: This is not new. It was tried, as almost everything you can imagine,
: at the turn of the century when the most talented and innovative people
: focussed on the bicycle. This and the Pulstar hub did not survive for
: the complexity and lack of redeeming merit.
Well I guess "time will tell". Myself and two friends all have the
CronoMetro wheel and we plan to "put it to the test". One of the people
is a friend of your's Jobst (Jeff Vance) and you know he rides pretty
hard. Jeff has had his wheel for for a few months and has had only one
minor problem with a single spoke loosing tension. Maybe is was a "waste of
money" but I have wasted more money on worse things.
[ more stuff deleted ]
: > Have you seen the wheel? Are you familiar with the design? I could
: > FAX you a picture. What do you think?
: That's OK. Although I haven't seen this one, I've seen its ancient
: predecessors and I think I've seen enough. Have you seen the BMW M/C
: wheel in which the spokes are straight and similarly have the nipples
: in the hub? The spokes cross from the hub to the opposite rim horn
: (the curled lip of the rim) so that the spoke is outside the tire.
: This allows using tubeless tires, builds a strange looking wheel and
: costs a pile. The lateral spoke angle is huge but then I haven't seen
: many laterally collapsed M/C wheels lately.
I'm kind of sorry you weren't interested in taking a look at the literature
on the wheel since many of us in "netland" seem to respect your opinion.
If you change your mind let me know.
RAFAEL RABAN
>
>I see no benefit here and besides, there is a bicycle with an all
>steel "Pulstar" hub built in 1900 or there abouts in the Wheelsmith
>antique collection. This is old stuff and it didn't work then either.
>The elbow protects the spoke head from taking the load straight on.
>The head is the most poorly formed part of the spoke and is a typical
>failure point as it is. Straight spokes only worsen the situation.
From my experience, the elbow is actually the most poorly formed part of the
spoke. When they break, they almost always break at the elbow (I use DT).
Although I don't have any experience with straight spokes, I would think they
would be stronger (I don't know about the hub design though).
\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//\\//
Rafael Raban (rmr3) ,__o ,__o _____ ,__o
ph. 8-0043 _- \ <, _- \ <, ____ _- \ <,
home 691-2666 ( ) / ( ) ( ) / ( ) _____ ( ) / ( )
Lehigh University breakaway
\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\
Jobst Brandt
> From my experience, the elbow is actually the most poorly formed
> part of the spoke. When they break, they almost always break at the
> elbow (I use DT). Although I don't have any experience with
> straight spokes, I would think they would be stronger (I don't know
> about the hub design though).
You must have missed the reason for this in earlier parts of this
discussion. These failures occur because the spoke is not properly
stress relieved after the wheel is built, not because there is anything
particularly different at the elbow. It should be obvious that the
material at the elbow must have the same grain alignment and uniformity
that the rest of the spoke has because it is merely bent into a curve
and not disturbed otherwise.
In contrast the head is rammed onto the end of the wire, crumpling the
grain structure and developing a small radius transition from the wire
diameter to the conical head. The head swaging process also develops
flash on the conical part. Threads are better off but they, in
themselves, form stress concentrators by the relatively small radius
in the root of the groove.
Jobst Brandt <jbr...@hpl.hp.com>
Harry Phinney
<Some explanation deleted>
: I had
: breakage in the same test situation.
: While I don't have accurate readings of the tension on the spokes I do know
: attempted to put large amounts of tension on the bent spokes the bends gave
: way and broke. I as well as another qualified builder I am working with have
: had the same experience.
: Any more questions?
Yes, I have an additional question, and a few comments. What brand of
"bent" spokes were you using? I have built hundreds if not thousands of
wheels, and cannot recall ever breaking a spoke by over-tensioning it in
a wheel. I will also say that in my experience spoke breakage is
generally due to either poor quality spokes, mismatched hubs and spokes
(i.e. spoke holes far too large for the spokes) or poorly built wheels.
Harry Phinney ha...@cv.hp.com
Blake A Storey
I have had several people mail me and attack my claims. For anyone out
there, PLEASE explain to me why having conventional spokes is such an extreme
advantage over the straight pull spokes?
-Blake
Joshua Putnam
In my experience, far and away the greatest advantage of
traditional spokes is availability/compatibility. They may not
be swaged DT or Wheelsmith, but I can get standard spokes in
just about any small town in the U.S., or even in rural India.
Almost all high quality rims and hubs are designed around
standard spokes, as are most wheel building and truing tools.
There's also the greater flexibility in wheel design, since
traditional hub flanges will work with almost any spoke angle
from radial lacing to four- or five-cross.
Finally, the design of a traditional hub flange is much simpler,
resulting in more affordable hubs for a given level of quality.
Chamberlain
: jbr...@hpl.hp.com (Jobst Brandt) writes:
: >I see no benefit here and besides, there is a bicycle with an all
: >steel "Pulstar" hub built in 1900 or there abouts in the Wheelsmith
: >antique collection. This is old stuff and it didn't work then either.
: >The elbow protects the spoke head from taking the load straight on.
: >The head is the most poorly formed part of the spoke and is a typical
: >failure point as it is. Straight spokes only worsen the situation.
I ÿûÿwill argue. You mean to tell us Jobst that you were alive in
1900 and tested those old hubs?ÿ ÿûHow do you know they don't
work. ÿûI would like to see more of your coþòmments based on
fact and experience, instead of thøñÿeoretical and hypoth%ethical
presumptiÿûonsÿû.ÿû
: Jobst -- you're the authority here, and I wouldn't presume to argue, but
: I'd like to know how can you tell that the failure occured at the head and
: not at the bend. It seems to me that there is very little spatial
: difference here and a fracture seemingly at the head could easily have
: originated elsewhere.
: My only related experience is with my old Hercules seven speed motorcycle,
: which also had straight pull spokes in the rear wheel. That wheel, the
:ÿû whole bike, actually, was damn near indestructible.
: Does bending a spoke incur no structural penalty? Does post-failure
: magnafluxing tell where the fracture originated, or does some other
: evidence tell you the head is the culprit?
Bendÿûing ÿûa ÿûspoke inÿûcurs more stress than cold forging a head.
ÿûWhen straÿûight pull spokes were introoduced toÿû theÿû SuperCross
world a few ÿûyears ago, they quÿûickly became more ÿûcommon
than standard spokes. It is becasue they are strongerÿû.
More people don't ÿûdo it becase Pulstar has a patent on the
applicationÿû for bicycles.ÿûÿû
Chamberlain
Jobst's hypothetical and theoretical mumbo-jumbo confuse
you. Just becasue something was tried in 1900, doesn't
mean it couldn't work today. I seriously
doubt Jobst was alive and old enough to test a product
that old. Let's hear some fact and experience based
comments.
When straight-pull spokes were introduced to the SuperCross
motorcycle world a few years ago, they almost completely
replaced straight pull. Perhaps someone actually in
that feild could support this for us.
Spokes almost always break at the bend. The bend is not
as strong as the head. However, if the hub doesn't
form a good and even seat for the spoke head, I can see
either point breaking. The seat for a straight pull
spoke is hard to mess up. It's not being tensioned
at an angle, so its evenly loaded. I've yet
to see a broken pullstar spoke (DT or WS that is).
There may have been failures in the earlier ones
made by Union, but I haven't seen one of those either.
I thought Jobst was a Road Rider, anyway. Have you
ever rode significantly on both types of Wheels?
I will presume no, since you are not even willing
to look at a CronoMetro wheel befor passing judgement.
By the way, IMHO, the cronometo wheel, which I have
seen, doen't provide enou˙gh benefits to outweight
the drawbacks. Limited Rim selection and
more difficulty truing the heel being the main
ones. How much weight do they claim to
rremove from the outside of the whhel> 11 grams
of alloy nipples hardly seems worth the added
complexity.
Jason Chamberlain
Gregg Mack
>When straight-pull spokes were introduced to the SuperCross
>motorcycle world a few years ago, they almost completely
>replaced straight pull.
I'm sorry, Jason, but I don't think you typed-in exactly what you
were thinking! If you did, then you lost me here..... ;-)
--
Gregg Mack -------- __o
gm...@paceline.sps.mot.com ------- _`\<,_
Motorola RISC - Austin, TX ------- (*)/ (*)
Jobst Brandt
>> Jobst Brandt writes:
>> I see no benefit here and besides, there is a bicycle with an all
>> steel "Pulstar" hub built in 1900 or there abouts in the Wheelsmith
>> antique collection. This is old stuff and it didn't work then either.
>> The elbow protects the spoke head from taking the load straight on.
>> The head is the most poorly formed part of the spoke and is a typical
>> failure point as it is. Straight spokes only worsen the situation.
> I will argue. You mean to tell us Jobst that you were alive in 1900
> and tested those old hubs? How do you know they don't work.
Ho Ho! You needn't play dumb...
I also thought of the idea and even saw some examples of straight
spokes, so I showed a picture of such a hub in "the Bicycle Wheel"
that has been in print for a while. It was apparent to me that this
type of spoke is weaker than the elbow spoke, and that such a hub was
good for one specific spoke pattern. As time went on, I found older
and older examples of "inventors" who thought this was a great idea.
Most of them had to try it to discover that it doesn't work as well as
the elbowed spoke, which after all was developed after the straight
spoke.
> I would like to see more of your comments based on fact and
> experience, instead of theoretical and hypothetical presumptions.
Nice try! You might use that concept on yourself first. It was your
contention that straight spokes are superior.
> Bending a spoke incurs more stress than cold forging a head. When
> straight pull spokes were introduced to the SuperCross world a few
> years ago, they quickly became more common than standard spokes. It
> is because they are stronger.
The "cold forged" jargon does not enhance this discussion. The whole
spoke is cold formed, and axially ramming a head onto a wire that has
longitudinal grain structure definitely makes a scramble of the
structure, both developing discontinuities in the grain and a sharp
transition in cross section at the juncture of the conical head and
cylindrical wire. Even if the grain orientation were not a problem,
just hanging the entire tension on the head would presents a
substantial durability problem at the transition from wire to the
head, the main problem in wire spokes.
> More people don't do it because Pulstar has a patent on the
> application for bicycles.
Wishful thinking. That patent isn't worth much due to "prior art" and
at best protects the specific shape of the protruding 'ears'. Maybe
if they defend their patent strongly enough, we'll be lucky and the
concept retreat to the museums sooner.
Jobst Brandt <jbr...@hpl.hp.com>
Scott McClellan
[lot's of staight put arguing and mud slinging deleted]
: I will presume no, since you are not even willing
: to look at a CronoMetro wheel befor passing judgement.
Maybe Jobst is just busy...
: By the way, IMHO, the cronometo wheel, which I have
: seen, doen't provide enou˙gh benefits to outweight
: the drawbacks. Limited Rim selection and
: more difficulty truing the heel being the main
: ones. How much weight do they claim to
: rremove from the outside of the whhel> 11 grams
: of alloy nipples hardly seems worth the added
: complexity.
I didn't buy the CronoMetro wheel because of weight savings.
I like the idea of saving some weight and I like the idea of moving
some weight toward the center of the wheel, but I liked other things
as well. The hub design itself is very nice. It is very easy to believe
that the hub is very rigid (a benefit if using front suspension).
Most importantly, I new somebody that rode on one for a couple of months
(and rode very hard). He specifically noticed improved handling and
like the rigidity of the wheel. He also caused a spoke to loosen, but
found it very easy to tighten up and did not even have to true the
wheel. I had mixed feelings about that experience. Why did the spoke
loosen in the first place? But at least it spoke well of the wheel that
it stayed true with only 23 spokes under tension.
I have only been able to get in a few rides on the wheel. I noticed
a difference immediately. Steering was more presice on a technical single
track I like to ride. I believe the wheel should get the credit since
the only other thing I changed was new brakes and bake levers. Maybe
I was having a good day (I don't think so). Maybe I just want to believe
that the wheel was worth the $239 it cost. Regardless I am happy so far.
Another note. The CronoMetro wheel is built with brass nipples which I
like. I weigh about 190 lbs. Few wheel builder recommend alloy nipple for
anybody but the light weight guys (and racers who get new wheels all the
time).
I agree with you comment about rim choice. I would like to have a Mavic
217 rim. This rim is not available from CronoMetro (or any other Mavic
rim for that matter). I like the Bontrager rim I got. It has a tall braking
surface and is pretty strong (based mostly on reputation - again time will
tell).
Tim Bradshaw
> When straight-pull spokes were introduced to the SuperCross
> motorcycle world a few years ago, they almost completely
> replaced straight pull. Perhaps someone actually in
> that feild could support this for us.
But motorbikes are quite different than bikes (I would guess that the
torques are much higher for instance), and the differing components of
the wheel may be nearer or further from their respective breaking
points on a motorbike.
--tim
Scott McClellan
: Scott McClellan writes:
: > I didn't buy the CronoMetro wheel because of weight savings. I like
: > the idea of saving some weight and I like the idea of moving some
: > weight toward the center of the wheel, but I liked other things as
: > well. The hub design itself is very nice. It is very easy to believe
: > that the hub is very rigid (a benefit if using front suspension).
: OK, lets get a little quantitative. How much weight is saved and how
: much lighter is the rim than a conventional rim and nipples? You'll
: notice the same riders who argue this case will ride Shamal and the
: like wheels that are substantially heavier than others.
I really don't understand why you are razzing me about the weight savings
issue. I said, and I quote, "I didn't buy the CronoMetro wheel because
of weight savings.". Having said that, the wheel is pretty light. Since
I am not a "roadie" I didn't even know what a Shamal wheel was. My friend
has informed me that they are areo-dynamic road wheels. If this is
true, it seems rather irrelevant. Why did you bring it up?
The facts are:
(1) The CronoMetro wheel is light (725 grams for the complete wheel -
not including the skewer).
(2) Some of the weight has been moved closed to the center (all the nipples
are in the center of the wheel not near the rim).
(3) I did not claim that this alone was a good reason to buy the wheel.
: > Most importantly, I new somebody that rode on one for a couple of
: > months (and rode very hard). He specifically noticed improved
: > handling and like the rigidity of the wheel. He also caused a spoke
: > to loosen, but found it very easy to tighten up and did not even
: > have to true the wheel. I had mixed feelings about that experience.
: > Why did the spoke loosen in the first place? But at least it spoke
: > well of the wheel that it stayed true with only 23 spokes under
: > tension.
: When this "new" guy felt rigidity, was this radial or lateral? This
: is the most outlandish claim I have yet heard for wheels. The tire
: weight and its inflation so overwhelm any structural characteristics
: that it would even be impossible to detect the difference between 24
: and 48 spokes in a front wheel. To what, specifically do you
: attribute this change in rigidity?
Since somebody else was claiming it was "rigid" I really don't know
what he meant. I have also ridden a few times on the wheel. I feel
that the bike handles better with that wheel. The "feeling" is the
steering is more precise. Maybe all three of us a suffering from a mass
delusion that this is the case but three different people have ridden
the wheel, and all three people (which rarely agree on anything) agree
that the wheel feels different and that the "new" feeling is better.
We all seem content to use the word "rigid". If this offends you in
some "theoretical sense" then we can try to find a better word.
How about "precise"?
In addition, I think the two biggest factors that contribute to the
feeling are as follows (not necessarily in order): (1) the hub has
an oversized axle and supposedly a very stiff body and (2) the spoke
pattern is radial. I have never ridden on any other wheel that has
either of these features. The "stiff" hub is supposed to improve steering
for people using front suspension. The theory is that the hub/axle assemlby
flexes somewhat allow that fork legs to move (slightly) independently.
This is only a theory, and one that you will probably find a reason to
disagree with. How much direct experience do you have with mountain
bike suspension? Either having a stiffer hub actually does help (with
front suspension) or there are dozens of hub manufacturers taking
advantage of the "mass hysteria" that currently plagues the mountain bike
buying public. Either way I buy into it (to a point), and I think
my new wheel works better than my old whel (so far).
As far as the radial spoke pattern goes, I don't know if or why it
would make the wheel feel different, but it or something else does!
I have been told by other people (that did not ride with bare rims
on hard wood floors) that they could feel the difference in radially
laced wheels.
: > I have only been able to get in a few rides on the wheel. I noticed
: > a difference immediately. Steering was more precise on a technical
: > single track I like to ride. I believe the wheel should get the
: > credit since the only other thing I changed was new brakes and bake
: > levers. Maybe I was having a good day (I don't think so). Maybe I
: > just want to believe that the wheel was worth the $239 it cost.
: > Regardless I am happy so far.
: This entire thread reminds me of "The Princess and the Pea". What and
: how do you feel these things? Was there a tire on the wheel, or was
: this a rim on the wooden floor test? I hope you realize that the
: rigidity of a conventional wheel is about 100x greater than that of
: its tire under normal inflation.
I have never read "The Princess and the Pea". Is it required reading
at HP labs? In the money making divisions within HP we rarely have time
to read such theoretical works.
Yes there was a tire on the wheel. We did not test it on the living
room floor. I really hadn't thought about it prior to your berating me,
but the tire is definitely alot less rigid than the wheel (or any decent
wheel for that matter). I guess that means that we probably could not
feel increased rigidity (at least radial rigidity - I'm not sure I buy
the argument for lateral rigidity).
: > Another note. The CronoMetro wheel is built with brass nipples which
: > I like. I weigh about 190 lbs. Few wheel builder recommend alloy
: > nipple for anybody but the light weight guys (and racers who get new
: > wheels all the time).
: I am surprised that you don't say that you can feel this difference as
: well, it being in the realm of things you have felt.
First of all I found out that I was wrong. The CronoMetro wheel uses
alloy nipples so ignore what I said. However, if they were brass I'm
sure I could feel the difference, couldn't anybody?
: > I agree with you comment about rim choice. I would like to have a
: > Mavic 217 rim. This rim is not available from CronoMetro (or any
: > other Mavic rim for that matter). I like the Bontrager rim I got. It
: > has a tall braking surface and is pretty strong (based mostly on
: > reputation - again time will tell).
: I think you should have begun with this last statement because for the
: time that you have tested these, even the whackiest hub, spoke, and
: rim combination would stand up. Of course, we never hear the
: follow-up report on these rave inventions anyway. We just have to
: assume that things "didn't work out" when the product vanishes from
: the novelty showcase at the bike shop, never to be seen again. Of
: course these disappearances occur through the Campagnolo-Mavic-Shimano
: axis conspiracy.
I have not made any actual claims (yet) as to the durability of the wheel.
In fact I have called under question in all of my posts the fact that one
of the spokes loosened on my friends wheel. This makes me suspicious.
I will let you guys know if my wheel breaks. I promise. Even you Jobst
who claims to not care.
On the "Campagnolo-Mavic-Shimano axis" conspiracy: Of course it is a
conspiracy! Everybody knows that! If you deny it, you must be working
for one (or more) of "THEM"! I don't know much about Campagnolo or Mavic
(again I am not a "roadie"), but Shimano does seem to do some strange
things. Like coming up with "compact drive" (which is not better in anyway
I can determine and is worse in some ways). This smells like "planned
obsolescence" to me. I don't think "conspiracy" is the BEST word for
it, but it works OK for me. Would you prefer that there were only three
manufactures of bike parts (Campagnolo, Mavic, and Shimano)? What's wrong
with a little "friendly" competition?
: Jobst Brandt <jbr...@hpl.hp.com>