Vibration damping

[Dan Connelly]

[email protected] wrote:
>
> The ideal would be while the bike's being ridden on the road

But it should be ridden by a stationary mass. Riders will invariably apply
secondary impulses, making the isolation path ambiguous. For example, if
the rider applies vibrations to the seat, then the perfectly isolating
frame would have an infinite seat-to-hub ratio, on a perfectly smooth road.

Dan

 

[Ozark Bicycle]

[email protected] wrote:
> jim beam wrote:
> >
> >
> > ok, as far as structures like frames are concerned, stiffness is vital,
> > hence the interest in modulus.
>
> Please.
>
> If stiffness is "vital" it would be the stiffness of the structure, not
> the inherent stiffness of the material itself. As any cycling
> metallurgist must know, aluminum has an elastic modulus about one third
> that of steel - IOW, it's three times limper than steel - yet it is
> usually used to make the stiffest frames.
>
> > as far as our kind of 6/4 alloys are
> > concerned, they also happen to have a higher yield and uts than 3/2.5.
> > as you question, those are not necessarily related, but as a comparison
> > between these two alloy classes, they happen to go hand in hand. the
> > fact that our 6/4 has higher modulus and more importantly, specific
> > modulus, happens to be a huge advantage - not something that can be
> > dismissed with incorrect data about workability & weldability.
>
> The choice of material for any product won't be governed by a simple
> listing of mechanical properties. If that were the case, we'd be
> riding nothing but beryllium frames. There are advantages and
> disadvantages to all materials, and good designers make good - but
> different - decisions based on properties, manufacturing
> considerations, costs & benefits.
>
> I'd say Mark's website did an excellent job of describing all the
> above, and laying out the rationale for his design choices.
>

Agreed. If all manufacturer's sites and literature were as factual and
BS-free as Mark Hickey's, the bicycle marketplace would be a much
better and saner place. Mark claims to make alot of sales to engineers;
I can see why.



> - Frank Krygowski

 

[Ozark Bicycle]

Sandy wrote:
> Dans le message de news:[email protected],
> Jasper Janssen <[email protected]> a réfléchi, et puis a déclaré :
> > On Fri, 9 Dec 2005 11:22:08 +0100, "Sandy" <[email protected]> wrote:
> >
> >> Long ago is exactly right. Before the legislation and regulation
> >> (US Code, CFR, myriad individual state control). Your short course
> >> in business law gave you an inadequate grasp of this subject - sorry.
> >
> > But you, from the incredibly high ivory towers of Paris, know much
> > more about US law, right? Quit the snide remarks and either put your
> > money where your mouth is or leave.
> >
> > Jasper
>
> Rude, aren't you.
> US lawyer as well, admitted and practiced a long time in New York,
> Connecticticut for the most part, federal courts and admin agencies. What's
> your question about money ?
> And the signature lets you know that I'm outside Paris. Yes, I do know a
> ton more than you do about US law, not to mention a a couple dozen more
> national systems.
> Feet in mouth - tire levers won't help here.
> --


I notice you have avoided responding to this post:

http://tinyurl.com/d9ozd

Care to comment?

 

[Sandy]

Dans le message de
news:[email protected],
Ozark Bicycle <[email protected]> a réfléchi, et puis a
déclaré :
> Sandy wrote:
>> Dans le message de news:[email protected],
>> Jasper Janssen <[email protected]> a réfléchi, et puis a déclaré :
>>> On Fri, 9 Dec 2005 11:22:08 +0100, "Sandy" <[email protected]> wrote:
>>>
>>>> Long ago is exactly right. Before the legislation and regulation
>>>> (US Code, CFR, myriad individual state control). Your short course
>>>> in business law gave you an inadequate grasp of this subject -
>>>> sorry.
>>>
>>> But you, from the incredibly high ivory towers of Paris, know much
>>> more about US law, right? Quit the snide remarks and either put your
>>> money where your mouth is or leave.
>>>
>>> Jasper
>>
>> Rude, aren't you.
>> US lawyer as well, admitted and practiced a long time in New York,
>> Connecticticut for the most part, federal courts and admin agencies.
>> What's your question about money ?
>> And the signature lets you know that I'm outside Paris. Yes, I do
>> know a ton more than you do about US law, not to mention a a couple
>> dozen more national systems.
>> Feet in mouth - tire levers won't help here.
>> --
>
>
> I notice you have avoided responding to this post:
>
> http://tinyurl.com/d9ozd
>
> Care to comment?

Only since you asked.
The comments do not relate to misrepresentations. They refer to opinions
expressed. I also don't usually reply to a lawyer who quotes casebooks to
argue a viewpoint. Like it or not (and most American judges hate it),
statutory and regulatory law has displaced the inventivemess of "finding"
law from natural principles. Case law, when cited, has its place, but what
I addressed is the fact that "puffery" is generally an anachronistic
application, and is, in contemporary jurisprudence, used to buttress the
interpretation of statutory law.
OK ?
(Let's not let this detract from the fact that most of the science related
in this and many threads is relevant, but not conclusive of the truths or
falsehoods that marketing efforts may tend to overwhelm.)
--
Bonne route !

Sandy
Verneuil-sur-Seine FR

 

[Ozark Bicycle]

Sandy wrote:
> Dans le message de
> news:[email protected],
> Ozark Bicycle <[email protected]> a réfléchi, etpuis a
> déclaré :
> > Sandy wrote:
> >> Dans le message de news:[email protected],
> >> Jasper Janssen <[email protected]> a réfléchi, et puis a déclaré :
> >>> On Fri, 9 Dec 2005 11:22:08 +0100, "Sandy" <[email protected]> wrote:
> >>>
> >>>> Long ago is exactly right. Before the legislation and regulation
> >>>> (US Code, CFR, myriad individual state control). Your short course
> >>>> in business law gave you an inadequate grasp of this subject -
> >>>> sorry.
> >>>
> >>> But you, from the incredibly high ivory towers of Paris, know much
> >>> more about US law, right? Quit the snide remarks and either put your
> >>> money where your mouth is or leave.
> >>>
> >>> Jasper
> >>
> >> Rude, aren't you.
> >> US lawyer as well, admitted and practiced a long time in New York,
> >> Connecticticut for the most part, federal courts and admin agencies.
> >> What's your question about money ?
> >> And the signature lets you know that I'm outside Paris. Yes, I do
> >> know a ton more than you do about US law, not to mention a a couple
> >> dozen more national systems.
> >> Feet in mouth - tire levers won't help here.
> >> --
> >
> >
> > I notice you have avoided responding to this post:
> >
> > http://tinyurl.com/d9ozd
> >
> > Care to comment?
>
> Only since you asked.
> The comments do not relate to misrepresentations. They refer to opinions
> expressed. I also don't usually reply to a lawyer who quotes casebooks to
> argue a viewpoint. Like it or not (and most American judges hate it),
> statutory and regulatory law has displaced the inventivemess of "finding"
> law from natural principles. Case law, when cited, has its place, but what
> I addressed is the fact that "puffery" is generally an anachronistic
> application, and is, in contemporary jurisprudence, used to buttress the
> interpretation of statutory law.
> OK ?
> (Let's not let this detract from the fact that most of the science related
> in this and many threads is relevant, but not conclusive of the truths or
> falsehoods that marketing efforts may tend to overwhelm.)
> --

Here is a link to the Specialized "Tech Lab" site for Zertz:

http://tinyurl.com/ct7sy

First, click on "How it works". The claims are fairly tame and related
to Specialized's "tests", which are difficult or impossible for most
people to interpret.

Now, click on "See it in action". If that ain't "puff" (aka,
hype/exaggeration), what is it? Yet, this is what most consumers will
respond to, because they can "see" it.

 

[Mark Hickey]

"Ozark Bicycle" <[email protected]> wrote:

>Here is a link to the Specialized "Tech Lab" site for Zertz:
>
>http://tinyurl.com/ct7sy
>
>First, click on "How it works". The claims are fairly tame and related
>to Specialized's "tests", which are difficult or impossible for most
>people to interpret.
>
>Now, click on "See it in action". If that ain't "puff" (aka,
>hype/exaggeration), what is it? Yet, this is what most consumers will
>respond to, because they can "see" it.

WOW. Personally I'd be scared to death of any bike that puts 1" of
travel into the bottom 3" of their rigid fork (not to mention into the
rear/bottom few inches of their stays).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the apparently very solid $795 ti frame

 

[Mark Hickey]

jim beam <[email protected]> wrote:

>Mark Hickey wrote:
>> jim beam <[email protected]> wrote:
>>>dvt wrote:
>>>>jim beam wrote:
>>>>
>>>>>for instance, 6/4 [Ti] is superior to 3/2.5 because it has a higher
>>>>>modulus. that also means higher strength to weight ratio.
>>>>
>>>>I don't understand the cause/effect relationship between higher modulus
>>>>and higher strength/weight. Can you elaborate?
>>>
>>>yes, could be phrased better. will get back to you tonight - off to work.
>>
>> Happy googling. Jose did a fine job of answering for me (thanks,
>> Jose), so I won't waste the electrons.
>
>you were the kid in the schoolyard that would call names but wouldn't
>fight. and not smart enough to know when to keep quiet.

Hey, you were the one who had to run away and try to backpedal on the
bogus claims you made - I just stayed right here and am enjoying the
show. It looks like others have taken you to task down-thread, so
I'll continue to enjoy, apparently.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

 

[Mark Hickey]

jim beam <[email protected]> wrote:

<snip>

>yeah, like espousing straight gauge tube - which is inferior in fatigue,
>and eschewing 6/4 ti, a much superior material. a pig with lipstick is
>still a pig.

Heh. Boys and girls, see what happens when you believe all the glossy
ads you read in your Buycycling magazine?

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti with lipstick frame

 

[Mark Hickey]

jim beam <[email protected]> wrote:

>Jose Rizal wrote:

>> Your half-baked technical
>> posturing and consistent name-calling of those who shoot down your
>> falsities exposes you for what you have always been: a poser. Is the
>> pay-off you get really worth it?
>
>what's my payoff jose? am i selling you anything? get with the
>killfile if you don't like it - it's /real/ simple!

Translation: "Dang, I can't refute a word you said, so please go away
so I can maintain the illusion that I have a clue... at least to
myself."

Won't help, jim. You just keep digging your hole deeper.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

 

[Sandy]

Dans le message de news:[email protected],
Mark Hickey <[email protected]> a réfléchi, et puis a déclaré :
> "Ozark Bicycle" <[email protected]> wrote:
>
>> Here is a link to the Specialized "Tech Lab" site for Zertz:
>>
>> http://tinyurl.com/ct7sy
>>
>> First, click on "How it works". The claims are fairly tame and
>> related to Specialized's "tests", which are difficult or impossible
>> for most people to interpret.
>>
>> Now, click on "See it in action". If that ain't "puff" (aka,
>> hype/exaggeration), what is it? Yet, this is what most consumers will
>> respond to, because they can "see" it.
>
> WOW. Personally I'd be scared to death of any bike that puts 1" of
> travel into the bottom 3" of their rigid fork (not to mention into the
> rear/bottom few inches of their stays).
>
At the Paris salon, in October, I think it was LOOK that demonstrated their
equipment abuse testing machines. The fork pivot was held in a clamp, and
(some?) large force was applied to the dropouts which were connected by an
"axle". Closer to two inches of movement of the dropouts, and it was being
counted at over 100 000 cycles at that point. But that was only something
real that I (and a few hundred thousand others) saw - not a napkin
calculation. Maybe it won't fit into this forum.
--
Les faits relatés ici ne sont que pure fiction, et ne sauraient être
utilisés ou rapprochés d'une situation réelle existant ou ayant
existée

 

[Ozark Bicycle]

Mark Hickey wrote:
> "Ozark Bicycle" <[email protected]> wrote:
>
> >Here is a link to the Specialized "Tech Lab" site for Zertz:
> >
> >http://tinyurl.com/ct7sy
> >
> >First, click on "How it works". The claims are fairly tame and related
> >to Specialized's "tests", which are difficult or impossible for most
> >people to interpret.
> >
> >Now, click on "See it in action". If that ain't "puff" (aka,
> >hype/exaggeration), what is it? Yet, this is what most consumers will
> >respond to, because they can "see" it.
>
> WOW. Personally I'd be scared to death of any bike that puts 1" of
> travel into the bottom 3" of their rigid fork (not to mention into the
> rear/bottom few inches of their stays).
>


If you have a BS Meter, stuff like this Specialized hype is sure to
"pin" it. OTOH, if you don't have one......


> Mark Hickey
> Habanero Cycles
> http://www.habcycles.com
> Home of the apparently very solid $795 ti frame

 

[[email protected]]

Dan Connelly wrote:
> [email protected] wrote:
> >
> > The ideal would be while the bike's being ridden on the road
>
> But it should be ridden by a stationary mass.

Why? In real life, the bike's ridden by a human rider.

> Riders will invariably apply
> secondary impulses, making the isolation path ambiguous. For example, if
> the rider applies vibrations to the seat, then the perfectly isolating
> frame would have an infinite seat-to-hub ratio, on a perfectly smooth road.

First, I don't see how riders are going to apply any significant
impulses with frequencies higher than the pedaling rate. And if they
somehow did, those would be expected to be essentially identical on the
two frames.

In general, if you want to examine the effect of one variable, it's
best to hold everything else constant. Instrumenting an unloaded bike
isn't as good as a bike with a rider.

Neither is, I'd think, instrumenting a bike with a rigid weight on the
saddle - but it's better.

Really, the best choice would be to take a Zertz-equpped bike and
instrument the saddle with and without the Zertz, with a rider on the
road. That would get to the heart of the matter.

- Frank Krygowski

 

[[email protected]]

jim beam wrote:
> [email protected] wrote:
> >
> >
> > If stiffness is "vital" it would be the stiffness of the structure, not
> > the inherent stiffness of the material itself. As any cycling
> > metallurgist must know, aluminum has an elastic modulus about one third
> > that of steel - IOW, it's three times limper than steel - yet it is
> > usually used to make the stiffest frames.
>
> you are the choicest bullshitter i've ever encountered.

Oh? You mean it's not true that the modulus of elasticity of aluminum
is one third that of steel? And it's not true that aluminum is used to
make very stiff frames? Or are you saying it's the stiffness of the
material that matters, even if it makes a noodle of a bike frame? (Are
you espousing frames made of beryllium wire?)

> there are 3 components krygowski:
> modulus, density & yield.

You're not explaining yourself very well. Sure, those are three very
nice mechanical properties. But are you pretending those are _all_ a
designer needs to look at in order to design a frame?

I'm saying the opposite - that a designer needs to consider other
engineering properties, some of which are not so precisely defined.
Fatigue resistance would matter. And ductility, at least for metals.
And weldability, or adaptability to other fastening techniques. And
perhaps corrosion resistance. And others, no doubt. And the designer
makes design choices based on the expected use, the material
properties, the manufacturing techniques and economics, among other
things.

It sounds like my world is less simple than yours.

> > I'd say Mark's website did an excellent job of describing all the
> > above, and laying out the rationale for his design choices.
>
> yeah, like espousing straight gauge tube - which is inferior in fatigue,
> and eschewing 6/4 ti, a much superior material.

All you've got to do is come up with a pile of Habanero frames
that failed in fatigue, and you've made one small point.

Obviously, I doubt very much you can do that. Consequently, I assume
even ruder insults will follow.

- Frank Krygowski

 

[Scott]

[email protected] wrote:
>
> First, I don't see how riders are going to apply any significant
> impulses with frequencies higher than the pedaling rate. And if they
> somehow did, those would be expected to be essentially identical on the
> two frames.
>
>
> - Frank Krygowski

The vibrations coming through the frame will resonate in buttisimo
region of the rider, creating a jiggling effect. Said jiggling often
magnifies the vibration, and if the rider is not careful, the result is
a harmonic resonance that causes the frame to vibrate itself apart.

 

[Java Man]

In article <[email protected]>,
[email protected] says...
>
> [email protected] wrote:
> >
> > First, I don't see how riders are going to apply any significant
> > impulses with frequencies higher than the pedaling rate. And if they
> > somehow did, those would be expected to be essentially identical on the
> > two frames.
> >
> >
> > - Frank Krygowski
>
> The vibrations coming through the frame will resonate in buttisimo
> region of the rider, creating a jiggling effect. Said jiggling often
> magnifies the vibration, and if the rider is not careful, the result is
> a harmonic resonance that causes the frame to vibrate itself apart.
>
. . but only if one does not conscientiously control the mass of the
ass . . .

Rick

 

[dvt]

RonSonic wrote:
> They are not attempting a
> suspension as your example describes...

Go to

http://www.specialized.com/bc/techlab_zertz.jsp?minisite=10080&a=b

Click on "see it in action."

They are advertising a suspension.

--
Dave
dvt at psu dot edu

 

[dvt]

jim beam wrote:
> ok, as far as structures like frames are concerned, stiffness is vital,
> hence the interest in modulus. as far as our kind of 6/4 alloys are
> concerned, they also happen to have a higher yield and uts than 3/2.5.
> as you question, those are not necessarily related, but as a comparison
> between these two alloy classes, they happen to go hand in hand.


I did a little searching on matweb.com and found that most 6/4 alloys
are stiffer and stronger than most 3/2.5 alloys.

> the
> fact that our 6/4 has higher modulus and more importantly, specific
> modulus, happens to be a huge advantage - not something that can be
> dismissed with incorrect data about workability & weldability.

I assume you direct your "incorrect data" comment at Habanero. Looking
at http://habcycles.com/techstuf.html#tubes, I don't see any mention of
workability and weldability. Are you referring to something else?

> for a potted summary, check:
>
> http://www.reynoldscycles.co.uk/compproperties.html

Their Ti data seems in line with the stuff I found at matweb.com.

--
Dave
dvt at psu dot edu

 

[dvt]

RonSonic wrote:
> On 12 Dec 2005 18:15:45 -0800, [email protected] wrote:
>>If you want to cushion things, you want the force to pass through the
>>rubber, not alongside it. Series, not parallel.

> Just like Jobst's handlebars wrapped with tape, the added material will reduce
> resonances and vibration. No it won't isolate, but it will damp.

It will isolate. Any vibrations in the handlebar must pass through the
tape in order to reach the rider.

--
Dave
dvt at psu dot edu

 

[dvt]

Dan Connelly wrote:
> dvt wrote:
>
>> jim beam wrote:
>>> what makes you say that? the c.f. frame shows order of magnitude
>>> differences below about 30 Hz, the ti frame almost zero. above that,
>>> frequency, the differences get even more interesting and
>>> substantially larger in places.

>> Jim, are you sure you're looking at the right graphs? The titles are
>> above the charts, not below.

> For part of the spectrum, the CF may do better -- he's correct. at higher
> freq, the Ti may do better.

A narrow part of the spectrum, yes. But "order of magnitude differences
below 30 Hz?" I don't see that.

--
Dave
dvt at psu dot edu

 

[Simon Cooper]

<[email protected]> wrote in message
news:[email protected]...
> But there was one startling exception. Tapping the top tube of
> the 531 tandem caused a beautiful, clear ring that persisted for at
> least four seconds! For kicks, I got my eletronic tuner out. It's a
> high E flat. It really was musical, and fairly loud.
>
> Incidentally, that resonant tandem frame has never given me any feeling
> of harshness. Not a fair comparison, I suppose, because a tandem
> really is a different machine. But again, I can't imagine that tubing
> vibrations in the musical range have any effect on ride comfort at all.
>

What you really need is a stoker with a xylophone hammer, and you can try
seeing what effect terrain and cadence have on the tone producted by the top
tube. See if EMI want the recording?