Another useless gimic?

Ritch <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

[snip]

Quoted message said:

Anyone who wants to pursue the matter will find it easiest
to search for colnago and "high-power" with google, that
being the name Colnago uses for this funny-looking frame
with a sort of diamond-cutout spliced into the chain-stay.

Me, I ride a Schwinn.

http://www.trialtir-usa.com/2003-colnago/c40/c40-testing.html

[snip]

Quoted message said:

Carl Fogel

I'm not JB, but according to the chart on the c40 page, a 100kg rider
will have 5% less vertical flex = 0.05 * 0.06mm = 0.003mm.

Let me guess... is that worth about 0.0000001psi in the tyre?

Yeah, that's a good point. There are so many other factors involved, how
could you possibly notice such a miniscule difference?
---
DFM

What ever happened to the Colnago dual down tube - the single down
tube that split into two when it reached the bottom bracket ? This
seemed to be the "fashion" a few years back with the top end Colnago
frames.

-R

Deep Freud Moors said:

Ritch <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

[snip]

Quoted message said:

Anyone who wants to pursue the matter will find it easiest
to search for colnago and "high-power" with google, that
being the name Colnago uses for this funny-looking frame
with a sort of diamond-cutout spliced into the chain-stay.

Me, I ride a Schwinn.

http://www.trialtir-usa.com/2003-colnago/c40/c40-testing.html

[snip]

Quoted message said:

Carl Fogel

I'm not JB, but according to the chart on the c40 page, a 100kg rider
will have 5% less vertical flex = 0.05 * 0.06mm = 0.003mm.

Let me guess... is that worth about 0.0000001psi in the tyre?

Yeah, that's a good point. There are so many other factors involved,
how could you possibly notice such a miniscule difference?
---
DFM

No problem. If you have an appropriate saddle of course.

--
Perre

You have to be smarter than a robot to reply.

"David L. Johnson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

highest mass tested, 100Kg, the new frame flexed not 600 mm, but 600/10000
mm. .06mm. The old frame flexed 580/10000 mm, .058mm That .002mm
difference is what they are advertising.

Well, every little counts.

Where's my credit card?

On 13 Oct 2003 19:51:48 -0700, [email hidden] (Carl Fogel) may

have said:

I don't know whether it actually does so or if such
stiffness matters, but I was surprised by how much
apparently ignorant scoffing your post generated.
You'd think that rec.bicycles.tech posters would be
curious about a weird new frame from a respected
manufacturer.

I feel the scoffing is warranted and deserved, based on what Colnago
admits in their own posted information.

The increased vertical flexure in the frame (about which they
conveniently failt to mention the point of measurement, but I'll take
it as likely that they are referring to flex at the dropouts) was
0.002 mm. Yes, that's right, less than one thousandth of an inch.
the alleged decrease in lateral flex was similar.

I believe they could have measured similar differences between
production samples of the old frame.

Bloody useless. It's a gimmick, pure and simple. If they're trying
to remain respected, they missed the mark here.

--
My email address is antispammed;
pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.

On Tue, 14 Oct 2003 11:25:02 GMT, "Per Elmsäter"

may have said:

Deep Freud Moors said:

Ritch <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

[snip]
>
> Anyone who wants to pursue the matter will find it easiest
> to search for colnago and "high-power" with google, that
> being the name Colnago uses for this funny-looking frame
> with a sort of diamond-cutout spliced into the chain-stay.
>
> Me, I ride a Schwinn.
>
> http://www.trialtir-usa.com/2003-colnago/c40/c40-testing.html
>
[snip]
>
> Carl Fogel

I'm not JB, but according to the chart on the c40 page, a 100kg rider
will have 5% less vertical flex = 0.05 * 0.06mm = 0.003mm.

Let me guess... is that worth about 0.0000001psi in the tyre?

Yeah, that's a good point. There are so many other factors involved,
how could you possibly notice such a miniscule difference?
---
DFM

No problem. If you have an appropriate saddle of course.

Perhaps one of Sheldon Brown's special granite ones...

--
My email address is antispammed;
pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.

On 13 Oct 2003 17:15:50 -0700, [email hidden] (Chalo)

Quoted message said:

(Alan Walker) said:

Saw a very expensive frame in my local bicycle shop with large
diamond-shaped holes in the chainstays. The carbon fibre tubes split
into two, then rejoined, leaving a hole.

That's what happens when bike buyers let silly people make their bikes
out of plastic. (They could have shaped the frame like a carousel
horse instead, but that would have been interesting, so of course they
didn't.)

It's much more difficult to include such ugly and worthless
contrivances when the maker is constrained to a proper material.

Bicycle makers should be "constrained" to "proper materials"
about as much as cyclists should be mandated to wear helmets.

The market will support or kill materials, gimmicks, and designs
on it's own, without any artificial constraint.

Quoted message said:

Chalo Colina

--
Rick Onanian

Simon Brooke said:

Quoted message said:

600/10000 mm. .06mm. The old frame flexed 580/10000 mm, .058mm That
.002mm difference is what they are advertising.

It's a very small amount.

I am amazed that that University lab would permit their name to be used.
Such a miniscule difference is probably well under the expected variation
between two frames of the same type. I do like the purposely misleading
scales on the charts, though. That's one for the books. Do you wonder
why they had it arranged to be in mm x 10e4 (the measurement in mm
was multiplied by 10000)? That gave numbers in the
hundreds. Would not mm x 10e2 be just as informative, giving numbers in
the single digits? No, since numbers in the hundreds look more
significant.

Yes, a small difference may be significant. But this is very, very small,
especially for a distance, chainstay length, of hundreds of mm. Probably
beyond the measurement accuracy of their instruments. The 100kg masses
used to produce this deflection are themselves not that accurately
determined. Noise factors such as deflection of the vice holding the
frame would easily be as large as this supposed measurement.

--

David L. Johnson

__o | the people can always be brought to the bidding of the leaders.
_`\(,_ | That is easy. All you have to do is tell them they are being
(_)/ (_) | attacked, and denounce the peacemakers for lack of patriotism
and exposing the country to danger. It works the same in any
<country. -- Hermann Goering

Quoted message said:

Quoted message said:

It's much more difficult to include such ugly and worthless
contrivances when the maker is constrained to a proper material.

Bicycle makers should be "constrained" to "proper materials"
about as much as cyclists should be mandated to wear helmets.

The market will support or kill materials, gimmicks, and designs
on it's own, without any artificial constraint.

Quoted message said:

Chalo Colina

--
Rick Onanian

Hey Rick, take a chill pill. Nobody was advocating artificially constraining
bicycle makers. Chalo was simply pointing out that if one were constrained
to working with the "proper" materials, one would find it difficult to
contrive what Colnago has. This isn't a debate about the free market, just
about silly gimmicks.

Rob Strickland

Werehatrack said:

On 13 Oct 2003 19:51:48 -0700, [email hidden] (Carl Fogel) may

have said:

I don't know whether it actually does so or if such
stiffness matters, but I was surprised by how much
apparently ignorant scoffing your post generated.
You'd think that rec.bicycles.tech posters would be
curious about a weird new frame from a respected
manufacturer.

I feel the scoffing is warranted and deserved, based on what Colnago
admits in their own posted information.

Colnago is the champion of silly designs, quite frankly. They've made
a reputation on good lugged steel frames back in the day and on the
C40. Most of their "innovations" are on par with the Hetchins "curly"
chain stay or the Bates "Diadrant" fork: cosmetics but of no real
value or significance.

Rick Onanian said:

Bicycle makers should be "constrained" to "proper materials"
about as much as cyclists should be mandated to wear helmets.

The market will support or kill materials, gimmicks, and designs
on it's own, without any artificial constraint.

To an extent, anyway. The trick in the bicycle industry is to
serialize such gimmickry so that people keep buying new bikes with the
latest (useless) gimmick. Since Colnago is at the center of this
discussion, let's point to them. They have had a series of gimmicks
over the years that last a year or two and then are quietly shelved in
favor of the next gimmick. Ernesto is no fool when it comes to
marketing: style over substance sells more bikes.

[email hidden] (Carl Fogel) wrote in message news:<[email hidden]>...

[snip]

A follow-up:

What I've seen is more like it!

It sounds as if the engineering crowd is
unimpressed with the minuscule increases
in horizontal stiffness claimed by Colnago
for their weird new chain-stay design.

But what if we look at it as a 5% (or whatever)
reduction in side-to-side thrashing power-loss?

That is, a rider puts out X amount of effort,
most of which (I hope) goes into overcoming
wind drag, rolling-resistance, inertia, and
broken glass.

But some effort is wasted in all sorts of
nooks and crannies, one of which is any
side-to-side flexing of the hideously stiff
something-or-other-hedron formed by the
seat-tube, chain-stays, seat-stays, and axle
(I read somewhere in another post that there's
a name for the geometry and that the little
cross-bar for the brake doesn't count.)

Everyone seems to agree that this side-to-side
motion is minute. My question is how much
effort is needed to create that tiny wiggle
in such a stiff arrangement of tubing? How much
would it help to reduce this particular loss by
5%?

If half of the overall X effort goes into
twisting my rear frame, then it's a 2.5% overall
improvement and worthwhile.

If only 1% of the overall X effort goes into
distorting my rear frame, then the potential
improvement is only 0.05% and getting hard to
justify.

And is any gain, regardless how large or small,
offset by the loss in the claimed greater vertical
flexing that's supposed to make the bike more
comfortable?

These are all figures too tricky for me to even
guess at, but at least now I know what the question
is--does that bizarre diamond-hole in the chain-stay
work to reduce horizontal deflection and increase
vertical deflection, and if so, are the effects large
enough to matter?

It may be pure marketing, it may be pure wishful
engineering, but I can't say that the ugliness
worries me--where would most of us be if homeliness
were grounds for rejection? Even Jobst Brandt admits
that there was a time when he was younger and more
beautiful.

Carl Fogel

[email hidden] (Chalo) wrote in message news:<[email hidden]>...

Quoted message said:

(Alan Walker) said:

Saw a very expensive frame in my local bicycle shop with large
diamond-shaped holes in the chainstays. The carbon fibre tubes split
into two, then rejoined, leaving a hole.

That's what happens when bike buyers let silly people make their bikes
out of plastic. (They could have shaped the frame like a carousel
horse instead, but that would have been interesting, so of course they
didn't.)

It's much more difficult to include such ugly and worthless
contrivances when the maker is constrained to a proper material.

Chalo Colina

Dear Chalo,

As I remember, you're a machinist and have forgotten more
about materials than I'll ever know, so please gear down
for a moment and speak to a layman.

Why is it harder to make these odd frame tubes with their
diamond holes out of metal (I assume this is your proper
material) than carbon fiber?

Remember, I'm so ignorant that I don't know whether my
ear holes are punched or bored.

(Hope you don't punch me. Doubt I'll be bored.)

Carl Fogel

On 14 Oct 2003 14:56:31 -0700, [email hidden] (Carl Fogel)

Quoted message said:

Dear Chalo,

<snip>

Quoted message said:

Remember, I'm so ignorant that I don't know whether my
ear holes are punched or bored.

(Hope you don't punch me. Doubt I'll be bored.)

At his weight, if he's any good at punching, you'd be screwed.

Quoted message said:

Carl Fogel

--
Rick Onanian

"David L. Johnson" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Carl Fogel said:

Below is a page that explains what advantages the Colnago engineers
believe their odd-looking frame provides, specifically less lateral and
vertical flexing.

I don't know whether it actually does so or if such stiffness matters, but
I was surprised by how much apparently ignorant scoffing your post
generated. You'd think that rec.bicycles.tech posters would be curious
about a weird new frame from a respected manufacturer.

Well, Colnago has also marketed frames with creased main tubes.

As far as this goes, according to the website you mention:

Quoted message said:

http://www.trialtir-usa.com/2003-colnago/c40/c40-testing.html

Indeed has a chart purporting to list the 5% increase in vertical flex.
But the scale is revealing, it gives flex in millimeters X 10e4. At the
highest mass tested, 100Kg, the new frame flexed not 600 mm, but 600/10000
mm. .06mm.

No, according to the chart the new frame flexed 6,000,000 mm. 6
kilometers under a 100 kg load. (The improvement between old and new
frames is left as an exercise...) Now, I realize that your
interpretation is probably closer to what they *meant* to say. But are
you going to take seriously the engineering acumen of a company that
can't even get the *sign* of the exponent right in materials sent out
for public consumption? Not to mention that the "load" is measured in
units of mass (kg) instead of force (N).

Carl Fogel said:

But what if we look at it as a 5% (or whatever)
reduction in side-to-side thrashing power-loss?

"Stiffness" is a subject that generates a lot of misconceptions, and
plain B.S. I reccomend Sheldon Browns article:

http://www.sheldonbrown.com/frame-materials.html

To summarise:
- vertical flex on a bike _frame_ is insignificant, next to tyre
and seat flex. Though frame geometry does affect comfort, frame flex doesnt.
- horizontal flex is greater, but its very elastic, so you
dont actually loose significant energy from it.

Quoted message said:

But some effort is wasted in all sorts of
nooks and crannies, one of which is any
side-to-side flexing of the hideously stiff

No, not if the flexing is elastic. Then you get the energy back.
Just like a diver or gymnast does from a springboard.

If you want to see how elastic steel is, try dropping a ball-bearing
onto a hard floor. Bounces quite well, doesnt it?
Elasticity is the key here.

Quoted message said:

My question is how much
effort is needed to create that tiny wiggle
in such a stiff arrangement of tubing?

Not much, and you get it back on the upstroke.

Quoted message said:

How much would it help to reduce this particular loss by
5%?

No help. Would be easy to do though, by using a larger seat-tube, if it
helped.

Quoted message said:

And is any gain, regardless how large or small,
offset by the loss in the claimed greater vertical
flexing that's supposed to make the bike more
comfortable?

Whoa! Way off. Anyone who claims that might read Sheldon etc. See above.

And BTW, steel vs Al makes no difference to frame flex, as they just
adjust the tube size to compensate for material stiffness & strength.

"David L. Johnson" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Simon Brooke said:

Quoted message said:

600/10000 mm. .06mm. The old frame flexed 580/10000 mm, .058mm That
.002mm difference is what they are advertising.

It's a very small amount.

I am amazed that that University lab would permit their name to be used.
Such a miniscule difference is probably well under the expected variation
between two frames of the same type. I do like the purposely misleading
scales on the charts, though. That's one for the books. Do you wonder
why they had it arranged to be in mm x 10e4 (the measurement in mm
was multiplied by 10000)? That gave numbers in the
hundreds. Would not mm x 10e2 be just as informative, giving numbers in
the single digits? No, since numbers in the hundreds look more
significant.

Yes, a small difference may be significant. But this is very, very small,
especially for a distance, chainstay length, of hundreds of mm. Probably
beyond the measurement accuracy of their instruments. The 100kg masses
used to produce this deflection are themselves not that accurately
determined. Noise factors such as deflection of the vice holding the
frame would easily be as large as this supposed measurement.

David L. Johnson

Dear David,

This is the kind of comment that I was hoping for--thanks.
If I follow your points, any effects claimed are likely to
be more random variation than the result of the weird frame,
all exaggerated for marketing purposes.

Even a clod like me gets a little suspicious of those graphs,
which don't seem to show much difference.

I do have one timid question.

I have no idea how such tests are performed, but wouldn't it
be sensible to duplicate the 100 kg mass by using the same
physical weight on each frame? That is, load the same 100 kg
plate from a barbell onto each frame to guarantee no variation
in that parameter, regardless of what the exact mass happens
to be? Or is there an engineering reason for using two weights
marked 100 kg that I'm missing?

Carl Fogel

"David L. Johnson" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Alan Walker said:

Saw a very expensive frame in my local bicycle shop with large
diamond-shaped holes in the chainstays. The carbon fibre tubes split into
two, then rejoined, leaving a hole.

I saw one advertised with an "elastomer insert" stuffed into such a hole.
Is this the same bike? The "elastomer" was kind of transparent.

i havent seen a chainstay elastomer insert, but i think ive seen a few
Specialized road bikes with carbon forks which have holes and what
look like big silicone inserts in 'em. i just sighed to myself,
pondered the power of marketing, and patted my surly to let her know i
still loved her.

ant said:

Quoted message said:

I saw one advertised with an "elastomer insert" stuffed into such a
hole. Is this the same bike? The "elastomer" was kind of transparent.

i havent seen a chainstay elastomer insert, but i think ive seen a few
Specialized road bikes with carbon forks which have holes and what look
like big silicone inserts in 'em.

That's the one. Not what the original thread was about, but what I had
seen.

Quoted message said:

i just sighed to myself, pondered the
power of marketing, and patted my surly to let her know i still loved her.

--

David L. Johnson

__o | Become MicroSoft-free forever. Ask me how.
_`\(,_ |
(_)/ (_) |

Carl Fogel said:

I have no idea how such tests are performed, but wouldn't it be sensible
to duplicate the 100 kg mass by using the same physical weight on each
frame? That is, load the same 100 kg plate from a barbell onto each frame
to guarantee no variation in that parameter, regardless of what the exact
mass happens to be? Or is there an engineering reason for using two
weights marked 100 kg that I'm missing?

It would be sensible to do that, yes. On the other hand, a "difference"
that is within the statistical variation of the design is meaningless. A
cynic would wonder how many new/old frame combinations they had to test
before they got even that much difference. But the test equipment, which
is usually cobbled together from what is available in the lab, certainly
had enough variability in it itself to nullify any significance of that
result. Every time you attach/detach a frame from the test bed, errors of
that size -- we are talking 10^(-7) meters here -- are inevitable.

--

David L. Johnson

__o | Some people used to claim that, if enough monkeys sat in front
_`\(,_ | of enough typewriters and typed long enough, eventually one of
(_)/ (_) | them would reproduce the collected works of Shakespeare. The
internet has proven this not to be the case.