| |
Main
Date: 19 Jun 2007 18:18:48
From:
Subject: High Speed Shimmy
|
I know this is a well worn topic, but, I've experienced shimmy with my
new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
same hills for 15 years with no problems (for the past 8 years on
Cannondale, which, sadly developed a cracked frame). The shop
tightened the spokes, which helped but did not solve the problem.
Anyway, the point of the post is to poll folks - is this a Lightspeed
issue?
Thanks
Matt
|
|
| |
Date: 25 Jun 2007 19:17:12
From: almost_fast@yahoo.com
Subject: Re: High Speed Shimmy
|
> Your bike's front wheel may stay pointed straight ahead during shimmy.
> Mine doesn't.
>
> --
> Dave
> dvt at psu dot edu
Interesting. What's the peak-to-peak lateral steering excursion?
|
| | |
Date: 26 Jun 2007 09:51:49
From: dvt
Subject: Re: High Speed Shimmy
|
almost_fast@yahoo.com wrote:
>> Your bike's front wheel may stay pointed straight ahead during shimmy.
>> Mine doesn't.
>>
>> --
>> Dave
>> dvt at psu dot edu
>
> Interesting. What's the peak-to-peak lateral steering excursion?
Looking at the handlebars as I shimmied along to work this morning, the
ends of the handlebars were moving back and forth an inch or two
peak-to-peak. This was minor shimmy, not enough to make me put my hands
on the handlebars. I've had a lot worse.
--
Dave
dvt at psu dot edu
Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)
|
| |
Date: 24 Jun 2007 17:43:19
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 24, 1:31 pm, jim beam <spamvor...@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mn...@speakeasy.net>,
> > jim beam <spamvor...@bad.example.net> wrote:
>
> >> Tim McNamara wrote:
> >>> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadn...@speakeasy.net>,
> >>> jim beam <spamvor...@bad.example.net> wrote:
>
> >>>> Tim McNamara wrote:
> >>>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytn...@speakeasy.net>,
> >>>>> jim beam <spamvor...@bad.example.net> wrote:
>
> >>>>>> Tim McNamara wrote:
> >>>>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudn...@speakeasy.net>,
> >>>>>>> jim beam <spamvor...@bad.example.net> wrote:
>
> >>>>>>>> Tim McNamara wrote:
> >>>>>>>>> In article <l2Jei.17444$y_7.7...@newssvr27.news.prodigy.net>,
> >>>>>>>>> "Mike Jacoubowsky" <mik...@ix.netcom.com> wrote:
>
> >>>>>>>>>>>>>> This comes up so often at my end of the business. We had
> >>>>>>>>>>>>>> one person who was terrified there was something very
> >>>>>>>>>>>>>> wrong with her bike because she could get it to
> >>>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
> >>>>>>>>>>>>>> road when there was a crosswind on a cold day. *All*
> >>>>>>>>>>>>>> those things had to exist for the shimmy to occur. And
> >>>>>>>>>>>>>> yet it was the bike at fault.
> >>>>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
> >>>>>>>>>>>>> the resonance of the frame and wheels should be
> >>>>>>>>>>>>> different, not coincident.
> >>>>>>>>>>>> A bike is not stable without a rider on it. Do you
> >>>>>>>>>>>> actually disagree with this?
> >>>>>>>>>>> in that the contact patch of the tire trails behind the
> >>>>>>>>>>> fork angle's intersection with the road, yes it is
> >>>>>>>>>>> inherently stable.
> >>>>>>>>>> So you could give the bike a push, without a rider on it,
> >>>>>>>>>> and it would go exactly how far before falling over?
>
> >>>>>>>>>> in that the
> >>>>>>>>>>> spring constants of both frame and tires give resonant
> >>>>>>>>>>> frequencies well above any frequency that can gain any
> >>>>>>>>>>> significant amplitude, yes, it is inherently stable.
>
> >>>>>>>>>>>> And, if you don't, do you understand the ramifications of
> >>>>>>>>>>>> it?
> >>>>>>>>>>> you're working with incomplete information.
> >>>>>>>>>> What information did I leave out?
> >>>>>>>>> You don't have jim's apperceptive mass. He can see subtle
> >>>>>>>>> reasons for these phenomena that are obscure to the rest of
> >>>>>>>>> us mere mortals.
> >>>>>>>> one thing's for sure: there's a helluva lot that's obscure to
> >>>>>>>> retards.
> >>>>>>> Well, obscure to you anyway.
>
> >>>>>>>>> You see, jim was a metallurgist whereas you've only been a
> >>>>>>>>> bike shop owner for the past 30 years or so.
> >>>>>>>> with all due respect to bike store owners, 30 years on the job
> >>>>>>>> doesn't automatically make them scientists expert in analysis
> >>>>>>>> of this kind of problem. just like window frame fitters
> >>>>>>>> turned psychologists aren't automatically good at the most
> >>>>>>>> basic of math concepts.
> >>>>>>> That's "glazier" to you. :-) Of course, by the same token
> >>>>>>> metallurgists aren't automatically good at mechanical
> >>>>>>> engineering- as the mechanical engineers have been pointing out
> >>>>>>> to you for years.
> >>>>>> funny. like it took a metallurgist to point out that the
> >>>>>> tensiometer math in "the book" had omitted spoke stiffness -
> >>>>>> that's supposed to be "mechanical engineering". but you'd
> >>>>>> already spotted that error hadn't you timmy - you were just
> >>>>>> waiting for the right time to say something.
> >>>>> Nope, hadn't noticed. But since the issue had already been
> >>>>> discussed by Jobst and others long before you turned up in the
> >>>>> newsgroup, I was aware of it.
> >>>> really, so after this so-called "discussion of which you were
> >>>> previously aware", you were still deceived. doesn't say much for
> >>>> your mental acuity. does it timmy.
> >>> I wrote that poorly. I hadn't noticed the spoke stiffness issue
> >>> when I read "The Bicycle Wheel" for the first time or two. Once I
> >>> started participating in the newsgroup, ca. 1993, the issue was
> >>> under discussion somewhere around that time.
> >> and unresolved.
>
> > Correct.
>
> you participated but didn't resolve? my, that was useful of you timmy.
> you should have used a gaussian model.
>
>
>
> >>> Joe Riel and Tuns Lee made it definitive later-
> >> yes, after i raised it.
>
> > It had been raised in the past, which you overlook in your usual
> > self-serving manner (you should look up "self-serving bias" too). You
> > might have regurgitated that iteration, I don't recall. But you didn't
> > actually bother to be involved in coming up with the proof, suggesting
> > once again that it was beyond you despite your grandiose claims.
>
> the bottom line, retard, is that i care that it gets resolved. i
> provoke discussion accordingly. sometime i contribute the solution,
> sometime others get there first. as long as it gets resolved, the rest
> is unimportant. you on the other hand just sit there, pick fights with
> people that dare question the status quo and call people that say things
> you don't understand, in a manner you don't like, liars. that makes you
> a retard. that's not "retard" as an epithet or insult, merely statement
> of fact. you don't get it. you're stupid, combative and incapable of
> logic. further, you're incapable of learning - you /are/ a retard.
>
> <snip remaining crap>- Hide quoted text -
>
> - Show quoted text -
if yawl want to use something try lethal dose of nocacaine
|
| |
Date: 24 Jun 2007 13:36:56
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 24, 9:09 am, "andresm...@aol.com" <andresm...@aol.com > wrote:
> On Jun 23, 9:38 pm, datakoll <datak...@yahoo.com> wrote:
>
> > > On a dark desert highway
> > > Cool wind on my face
> > > warm smell of colitas...
>
> > AND THE LIGHTS COME ON
> > SOMEBODY SHOUTS
> > EVERYBODY OUTTA DA VAN
> > DIS EEEES DA BODA PATROL
>
> but since we were riding
> we kept on going
> but the patrol screams
> scared us shitless
> and our bikes went into
> a death wobble
> exacerbated by
> the effect of pot
SPINELESS!
|
| |
Date: 24 Jun 2007 06:09:33
From: andresmuro@aol.com
Subject: Re: High Speed Shimmy
|
On Jun 23, 9:38 pm, datakoll <datak...@yahoo.com > wrote:
> > On a dark desert highway
> > Cool wind on my face
> > warm smell of colitas...
>
> AND THE LIGHTS COME ON
> SOMEBODY SHOUTS
> EVERYBODY OUTTA DA VAN
> DIS EEEES DA BODA PATROL
but since we were riding
we kept on going
but the patrol screams
scared us shitless
and our bikes went into
a death wobble
exacerbated by
the effect of pot.
|
| |
Date: 24 Jun 2007 06:03:27
From: andresmuro@aol.com
Subject: Re: High Speed Shimmy
|
On Jun 24, 6:41 am, Johnny Sunset <sunsetss0...@yahoo.com > wrote:
> On Jun 24, 12:43 am, "jim beam" wrote:
>
> > ...
> > fuck you retard. i've put out for your dumb ass countless fucking
> > times. and all i get is your dumb ass calling me a liar BECAUSE YOU'RE
> > TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you think i'm going
> > to re-write all that same old stuff just to hear that same old shit from
> > the retard? cram it up your retarded dumb ass.
>
> Amazing show of maturity here. No wonder "jim beam" does not want his/
> her real name attributed.
>
> --
> Tom Sherman - Holstein-Friesland Bovinia
> The weather is here, wish you were beautiful
Especially with the lack of originality of the insults. the other day,
my 18 year old called me a "fucktard' after I was giving him grief.
Now, that is an insult worth putting your real name behind. My wife
and had never heard it and were laughing a lot. But "fucking retard"
is is so unoriginal!
"dumbass" is good because it signifies belonging to bikes.racing. if I
have to insult someone, I'll use fucktard.
Andres
|
| |
Date: 24 Jun 2007 05:41:14
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 24, 12:43 am, "jim beam" wrote:
> ...
> fuck you retard. i've put out for your dumb ass countless fucking
> times. and all i get is your dumb ass calling me a liar BECAUSE YOU'RE
> TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you think i'm going
> to re-write all that same old stuff just to hear that same old shit from
> the retard? cram it up your retarded dumb ass.
Amazing show of maturity here. No wonder "jim beam" does not want his/
her real name attributed.
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| |
Date: 24 Jun 2007 03:38:58
From: datakoll
Subject: Re: High Speed Shimmy
|
> On a dark desert highway
> Cool wind on my face
> warm smell of colitas...
AND THE LIGHTS COME ON
SOMEBODY SHOUTS
EVERYBODY OUTTA DA VAN
DIS EEEES DA BODA PATROL
|
| |
Date: 23 Jun 2007 18:25:00
From: andresmuro@aol.com
Subject: Re: High Speed Shimmy
|
On Jun 23, 7:16 pm, datakoll <datak...@yahoo.com > wrote:
> well, it was 5 pm.
> the wind blew cold from the west on US 6
> traveling at......
>
> anomaly?
> poor road surface?
> anyway, we never crash.
On a dark desert highway
Cool wind on my face
warm smell of colitas...
|
| |
Date: 24 Jun 2007 01:16:35
From: datakoll
Subject: Re: High Speed Shimmy
|
well, it was 5 pm.
the wind blew cold from the west on US 6
traveling at......
anomaly?
poor road surface?
anyway, we never crash.
|
| |
Date: 23 Jun 2007 15:53:49
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 23, 5:39 pm, Mike Jacoubowsky wrote:
> > but that's not the point. reality is, handle has NOTHING to do with
> > accuracy. the ridiculous way things are hereabouts,
>
> I just wanted to let that viewpoint air itself out on the 'net a bit more.
> It's one of the more-puzzling things I see people write.
>
> I should add that a "handle" doesn't necessarily mean something is less
> accurate, but rather that accountability, and thus credibility, is greatly
> reduced. Not eliminated, mind you, but very much reduced. In my humble
> opinion anyway.
Especially for people like Mike, Peter, Sheldon and Andrew where
posting misinformation could affect their living.
Would you purchase bicycles, parts or service from someone who was
not, as Sheldon would write, a usually reliable source?
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | |
Date: 24 Jun 2007 18:25:27
From: A Muzi
Subject: Re: High Speed Shimmy
|
> On Jun 23, 5:39 pm, Mike Jacoubowsky wrote:
>>> but that's not the point. reality is, handle has NOTHING to do with
>>> accuracy. the ridiculous way things are hereabouts,
>> I just wanted to let that viewpoint air itself out on the 'net a bit more.
>> It's one of the more-puzzling things I see people write.
>>
>> I should add that a "handle" doesn't necessarily mean something is less
>> accurate, but rather that accountability, and thus credibility, is greatly
>> reduced. Not eliminated, mind you, but very much reduced. In my humble
>> opinion anyway.
Johnny Sunset wrote:
> Especially for people like Mike, Peter, Sheldon and Andrew where
> posting misinformation could affect their living.
>
> Would you purchase bicycles, parts or service from someone who was
> not, as Sheldon would write, a usually reliable source?
Or a titanium railed leather saddle maybe?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | |
Date: 23 Jun 2007 15:57:32
From: jim beam
Subject: Re: High Speed Shimmy
|
Johnny Sunset wrote:
> On Jun 23, 5:39 pm, Mike Jacoubowsky wrote:
>>> but that's not the point. reality is, handle has NOTHING to do with
>>> accuracy. the ridiculous way things are hereabouts,
>> I just wanted to let that viewpoint air itself out on the 'net a bit more.
>> It's one of the more-puzzling things I see people write.
>>
>> I should add that a "handle" doesn't necessarily mean something is less
>> accurate, but rather that accountability, and thus credibility, is greatly
>> reduced. Not eliminated, mind you, but very much reduced. In my humble
>> opinion anyway.
>
> Especially for people like Mike, Peter, Sheldon and Andrew where
> posting misinformation could affect their living.
>
> Would you purchase bicycles, parts or service from someone who was
> not, as Sheldon would write, a usually reliable source?
>
why not? jobst has managed it for years - and he's got some serious
errors in his book.
|
| | | |
Date: 23 Jun 2007 23:27:56
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
>>>> but that's not the point. reality is, handle has NOTHING to do with
>>>> accuracy. the ridiculous way things are hereabouts,
>>> I just wanted to let that viewpoint air itself out on the 'net a bit
>>> more.
>>> It's one of the more-puzzling things I see people write.
>>>
>>> I should add that a "handle" doesn't necessarily mean something is less
>>> accurate, but rather that accountability, and thus credibility, is
>>> greatly
>>> reduced. Not eliminated, mind you, but very much reduced. In my humble
>>> opinion anyway.
>>
>> Especially for people like Mike, Peter, Sheldon and Andrew where
>> posting misinformation could affect their living.
>>
>> Would you purchase bicycles, parts or service from someone who was
>> not, as Sheldon would write, a usually reliable source?
>>
>
>
> why not? jobst has managed it for years - and he's got some serious
> errors in his book.
And he's accountable because he posts with his real name.
But for me? Doesn't matter so much from a business standpoint, as we sell
nothing, zero, nada, over the 'net. So posting with my real name actually
costs me money at times, as I spend a fair amount of time answering emails
from people with whom I'll never likely do business with.
Still, I'd never consider posting behind a facade. I've always felt it best
to be as transparent as possible. I'd have a difficult time reconciling two
personalities. And it would just seem dishonest. My parents didn't give me a
"secret" name only to be used for official purposes.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| | | | |
Date: 24 Jun 2007 16:21:39
From: Patrick Lamb
Subject: Re: High Speed Shimmy
|
On Sat, 23 Jun 2007 23:27:56 GMT, "Mike Jacoubowsky"
<MikeJ@ChainReaction.com > wrote:
>>>> I should add that a "handle" doesn't necessarily mean something is less
>>>> accurate, but rather that accountability, and thus credibility, is
>>>> greatly
>>>> reduced. Not eliminated, mind you, but very much reduced. In my humble
>>>> opinion anyway.
>>>
>>> Especially for people like Mike, Peter, Sheldon and Andrew where
>>> posting misinformation could affect their living.
>>>
>>> Would you purchase bicycles, parts or service from someone who was
>>> not, as Sheldon would write, a usually reliable source?
>>
>> why not? jobst has managed it for years - and he's got some serious
>> errors in his book.
>
>And he's accountable because he posts with his real name.
>
>But for me? Doesn't matter so much from a business standpoint, as we sell
>nothing, zero, nada, over the 'net. So posting with my real name actually
>costs me money at times, as I spend a fair amount of time answering emails
>from people with whom I'll never likely do business with.
Well, not _quite_ zero. Little brudda bought a bike[1] from your shop
last year, based on my steering him your direction based on your
history of posting reliable information and his (relative) proximity.
So that non-commercial activity does some good, after all!
[1] OK, so he ended up buying a leftover from the previous year, on
sale. OTOH, he's still riding it!
Pat
Email address works as is.
|
| | | | | |
Date: 24 Jun 2007 22:06:51
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
>>But for me? Doesn't matter so much from a business standpoint, as we sell
>>nothing, zero, nada, over the 'net. So posting with my real name actually
>>costs me money at times, as I spend a fair amount of time answering emails
>>from people with whom I'll never likely do business with.
>
> Well, not _quite_ zero. Little brudda bought a bike[1] from your shop
> last year, based on my steering him your direction based on your
> history of posting reliable information and his (relative) proximity.
> So that non-commercial activity does some good, after all!
>
> [1] OK, so he ended up buying a leftover from the previous year, on
> sale. OTOH, he's still riding it!
>
> Pat
Pat: Thanks, that's true, there will be some local folk reading usenet and
hopefully not too put off by what I have to say! : >)
But it's a pretty inefficient way to go about trying to impress potential
customers. HOWEVER- what I find really useful posting here is that I learn
what sort of things my customers might want to know or have, but aren't
asking. Kind of a way to look inside the minds of a whole lot of people and
learn how to help them. Look at it this way- I get to experiment here
without the same risk that I'd have on the customers in my shop.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Patrick Lamb" <pdl678NOSPAM@comcast.net > wrote in message
news:msnt73dvrcjpt18bo3he6oe4pgdqkt5a63@4ax.com...
> On Sat, 23 Jun 2007 23:27:56 GMT, "Mike Jacoubowsky"
> <MikeJ@ChainReaction.com> wrote:
>>>>> I should add that a "handle" doesn't necessarily mean something is
>>>>> less
>>>>> accurate, but rather that accountability, and thus credibility, is
>>>>> greatly
>>>>> reduced. Not eliminated, mind you, but very much reduced. In my humble
>>>>> opinion anyway.
>>>>
>>>> Especially for people like Mike, Peter, Sheldon and Andrew where
>>>> posting misinformation could affect their living.
>>>>
>>>> Would you purchase bicycles, parts or service from someone who was
>>>> not, as Sheldon would write, a usually reliable source?
>>>
>>> why not? jobst has managed it for years - and he's got some serious
>>> errors in his book.
>>
>>And he's accountable because he posts with his real name.
>>
>>But for me? Doesn't matter so much from a business standpoint, as we sell
>>nothing, zero, nada, over the 'net. So posting with my real name actually
>>costs me money at times, as I spend a fair amount of time answering emails
>>from people with whom I'll never likely do business with.
>
> Well, not _quite_ zero. Little brudda bought a bike[1] from your shop
> last year, based on my steering him your direction based on your
> history of posting reliable information and his (relative) proximity.
> So that non-commercial activity does some good, after all!
>
> [1] OK, so he ended up buying a leftover from the previous year, on
> sale. OTOH, he's still riding it!
>
> Pat
>
> Email address works as is.
|
| | | | |
Date: 23 Jun 2007 17:21:36
From: jim beam
Subject: Re: High Speed Shimmy
|
Mike Jacoubowsky wrote:
>>>>> but that's not the point. reality is, handle has NOTHING to do with
>>>>> accuracy. the ridiculous way things are hereabouts,
>>>> I just wanted to let that viewpoint air itself out on the 'net a bit
>>>> more.
>>>> It's one of the more-puzzling things I see people write.
>>>>
>>>> I should add that a "handle" doesn't necessarily mean something is less
>>>> accurate, but rather that accountability, and thus credibility, is
>>>> greatly
>>>> reduced. Not eliminated, mind you, but very much reduced. In my humble
>>>> opinion anyway.
>>> Especially for people like Mike, Peter, Sheldon and Andrew where
>>> posting misinformation could affect their living.
>>>
>>> Would you purchase bicycles, parts or service from someone who was
>>> not, as Sheldon would write, a usually reliable source?
>>>
>>
>> why not? jobst has managed it for years - and he's got some serious
>> errors in his book.
>
> And he's accountable because he posts with his real name.
but he's not! those that are deceived accept it. [the otherwise
excellent and worthy sheldon for instance - he effectively endorses it
by hosting the jobstian faq's.] any critic gets bullied by the herd of
naysayers who are just in it for the theater, not the engineering or
science. on an allegedly "tech" news group! seriously, some of them
couldn't see an engineering barn door if they were nailed to it face
first, but they'll happily throw stones if they see conflict. accuracy?
that's no fun.
>
> But for me? Doesn't matter so much from a business standpoint, as we sell
> nothing, zero, nada, over the 'net. So posting with my real name actually
> costs me money at times,
eh? no it doesn't. unless you're trying to say you spend time here in
preference to earning activities. and and that having your business
name attached to each posting isn't free advertising.
> as I spend a fair amount of time answering emails
> from people with whom I'll never likely do business with.
>
> Still, I'd never consider posting behind a facade. I've always felt it best
> to be as transparent as possible. I'd have a difficult time reconciling two
> personalities. And it would just seem dishonest. My parents didn't give me a
> "secret" name only to be used for official purposes.
maybe you should consider it if you truthfully don't want to sell
anything. but that's not the case since you take advantage of the exposure.
|
| |
Date: 23 Jun 2007 13:00:36
From: Gary Young
Subject: Re: High Speed Shimmy
|
On Sat, 23 Jun 2007 10:51:12 -0700, jim beam wrote:
<snip >
>>>> I wonder if "jim beam" would be so ready to snipe if he/she had to
>>>> use his/her real name on the postings?
>>> sure. utter bullshit doesn't need a nom-de-net.
>>
>> Then why use one?
>
>
> because i want to!
>
>> Who or what are you afraid of?
>>
>>
> er, you?
>
> but that's not the point. reality is, handle has NOTHING to do with
> accuracy.
Sure, that's the reason scientific journals accept anonymous articles and
don't waste their time with a silly thing like peer review. After all,
what's peer review other than an extra layer of authority superimposed
over something that should be judged just by the bare text alone?
> the ridiculous way things are hereabouts,
> http://www.theflatearthsociety.org/ would be given credence on r.b.t if
> they told you they were were stanford alumni.
|
| | |
Date: 23 Jun 2007 13:17:59
From: jim beam
Subject: Re: High Speed Shimmy
|
Gary Young wrote:
> On Sat, 23 Jun 2007 10:51:12 -0700, jim beam wrote:
> <snip>
>
>>>>> I wonder if "jim beam" would be so ready to snipe if he/she had to
>>>>> use his/her real name on the postings?
>>>> sure. utter bullshit doesn't need a nom-de-net.
>>> Then why use one?
>>
>> because i want to!
>>
>>> Who or what are you afraid of?
>>>
>>>
>> er, you?
>>
>> but that's not the point. reality is, handle has NOTHING to do with
>> accuracy.
>
> Sure, that's the reason scientific journals accept anonymous articles and
> don't waste their time with a silly thing like peer review.
anonymous writing goes back centuries gary. often for contentious
issues. studied history or literature much have you?
as for "peer review", that's as much of a red herring coming from you as
it is from jobst. he claims his book "has had much peer review over the
last 20 years"
http://groups.google.com/group/rec.bicycles.tech/msg/2b111c058444742b
but it's still full of fundamental errors. so what could possibly have
gone wrong? [sic]
> After all,
> what's peer review other than an extra layer of authority superimposed
> over something that should be judged just by the bare text alone?
authority? bare text? this is the point where your wheels fall off.
again.
>
>
>> the ridiculous way things are hereabouts,
>> http://www.theflatearthsociety.org/ would be given credence on r.b.t if
>> they told you they were were stanford alumni.
|
| |
Date: 23 Jun 2007 09:59:19
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 23, 8:55 am, "jim beam" (who?) anonymously snipes:
> Johnny Sunset wrote:
> > On Jun 23, 8:23 am, "jim beam" (who?) anonymously snipes:
> >> Tim McNamara wrote:
> >>> "jim beam" (who?) anonymously snipes:
> >>>> Tim McNamara wrote:
> >>>>> Mike Jacoubowskywrote:
> >>>>>>>>>> This comes up so often at my end of the business. We had one
> >>>>>>>>>> person who was terrified there was something very wrong with
> >>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
> >>>>>>>>>> descending this one particular road when there was a crosswind
> >>>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
> >>>>>>>>>> to occur. And yet it was the bike at fault.
> >>>>>>>>> it is. bike shouldn't do it under any circumstances. the
> >>>>>>>>> resonance of the frame and wheels should be different, not
> >>>>>>>>> coincident.
> >>>>>>>> A bike is not stable without a rider on it. Do you actually
> >>>>>>>> disagree with this?
> >>>>>>> in that the contact patch of the tire trails behind the fork
> >>>>>>> angle's intersection with the road, yes it is inherently stable.
> >>>>>> So you could give the bike a push, without a rider on it, and it
> >>>>>> would go exactly how far before falling over?
> >>>>>> in that the
> >>>>>>> spring constants of both frame and tires give resonant
> >>>>>>> frequencies well above any frequency that can gain any
> >>>>>>> significant amplitude, yes, it is inherently stable.
> >>>>>>>> And, if you don't, do you understand the ramifications of it?
> >>>>>>> you're working with incomplete information.
> >>>>>> What information did I leave out?
> >>>>> You don't have jim's apperceptive mass. He can see subtle reasons
> >>>>> for these phenomena that are obscure to the rest of us mere
> >>>>> mortals.
> >>>> one thing's for sure: there's a helluva lot that's obscure to
> >>>> retards.
> >>> Well, obscure to you anyway.
> >>>>> You see, jim was a metallurgist whereas you've only been a bike
> >>>>> shop owner for the past 30 years or so.
> >>>> with all due respect to bike store owners, 30 years on the job
> >>>> doesn't automatically make them scientists expert in analysis of this
> >>>> kind of problem. just like window frame fitters turned psychologists
> >>>> aren't automatically good at the most basic of math concepts.
> >>> That's "glazier" to you. :-) Of course, by the same token
> >>> metallurgists aren't automatically good at mechanical engineering- as
> >>> the mechanical engineers have been pointing out to you for years.
> >> funny. like it took a metallurgist to point out that the tensiometer
> >> math in "the book" had omitted spoke stiffness - that's supposed to be
> >> "mechanical engineering". but you'd already spotted that error hadn't
> >> you timmy - you were just waiting for the right time to say something.
>
> >>>>>>>> Are you suggesting that a shaking rider should have no effect on
> >>>>>>>> a bike's resistance to shimmy?
> >>>>>>> the rider should not be able to make the bike shimmy. with rider
> >>>>>>> load, the resonance of the frame and of the wheels should not be
> >>>>>>> coincident. period. many old fashioned steel frames /do/ shimmy
> >>>>>>> because their torsional stiffness is not very high, and in the
> >>>>>>> old days of undished wheels, it wasn't as much of a problem, but
> >>>>>>> now, with 10-speed ultra-dished wheels, it's a big deal. if we
> >>>>>>> can't have un-dished wheels, we can have torsionally stiff frames
> >>>>>>> where their designer has paid attention to this stuff. no
> >>>>>>> excuses.
> >>>>>> So you believe flimsy wheels are the culprit? I used to think so
> >>>>>> too. But after changing out wheels (lighter wheels exchanged for
> >>>>>> much-beefier, stiffer versions) for a number of people, without
> >>>>>> cure, that didn't appear to be the answer. I had much better
> >>>>>> success by changing the position of the handlebars.
> >>>>>> That's not to say that large frames aren't far more prone to
> >>>>>> shimmy than smaller ones. You're absolutely correct about that.
> >>>>>> But that wasn't the issue for the particular case I referenced. I
> >>>>>> didn't include the frame size; it was 56cm, center-to-top.
> >>>>>> Oops, I left out one other piece of information. The person whose
> >>>>>> bike shimmied that I mentioned also had to take one hand off the
> >>>>>> bars for the shimmy to occur. So you've got *5* things that had to
> >>>>>> exist for her bike to shimmy-
> >>>>>> #1: Only on this one particular road #2: Speed had to be 38mph #3:
> >>>>>> One hand off the bars #4: Crosswind #5: Cold
> >>>>>> So think about what I'm saying here. If it was warm, no shimmy.
> >>>>>> Hands on bars, no shimmy. Any other road, including descents at
> >>>>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind,
> >>>>>> no shimmy. For the sake of full disclosure, the only thing
> >>>>>> possibly unusual about this one stretch of road is that it's
> >>>>>> perfectly straight for a fairly good distance. I think that pretty
> >>>>>> much lays everything out on the table.
> >>>>>> Still think it was a problem with the bike? (And yes, we did try
> >>>>>> different wheels. She wouldn't consider changing her position on
> >>>>>> the bike, so we couldn't test for that.)
> >>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
> >>>>> Expert) and that if he says the problem is that the rear wheel is
> >>>>> too flexible, then that's the problem. If you replace the rear
> >>>>> wheel with a stiffer wheel and the bike still shimmies, jim is
> >>>>> still right- it's reality that's wrong.
> >>>> how would you know? you think i'm lying when i say that 5000 > 1600,
> >>>> so everything is bullshit to you. retard.
> >>> You're lying again, jim, just like you were back in that thread. You
> >>> keep coming up with different numbers- obviously you don't get the same
> >>> answer consistently when you add 2 + 2. I doubt your mathematics
> >>> abilities more and more. Or perhaps it's your memory.
> >> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
> >> you're an irredeemable fucking retard timmy!
>
> >> ***
>
> >> dear mrs mcnamara
>
> >> it is with regret that we must tell you to keep your son home for
> >> another week's suspension again this semester. he has been fighting
> >> with the other boys and is becoming increasingly disruptive in class.
> >> in addition, as discussed at our last meeting, his grades continue to be
> >> well below standard, and even with the remedial classes he's been
> >> attending, he has shown no ability to catch up.
>
> >> in consultation with his teachers and the school counselor therefore, it
> >> is our opinion that academic frustration and taunting from the other
> >> children are causing his behavior problems. in timmy's best interests
> >> therefore, we will will be making arrangements for him to attend happy
> >> valley retards school where his special needs can be better
> >> accommodated. you will be contacted directly by happy valley's
> >> admissions director, ms. u. gottabekiddingme, ph.d., and their learning
> >> difficulties specialist, dr. i. v. ritalin, who will be supervising his
> >> treatments.
>
> > FEEL THE LOVE!
>
> > I wonder if "jim beam" would be so ready to snipe if he/she had to use
> > his/her real name on the postings?
>
> sure. utter bullshit doesn't need a nom-de-net.
Then why use one? Who or what are you afraid of?
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | |
Date: 23 Jun 2007 10:51:12
From: jim beam
Subject: Re: High Speed Shimmy
|
Johnny Sunset wrote:
> On Jun 23, 8:55 am, "jim beam" (who?) anonymously snipes:
>> Johnny Sunset wrote:
>>> On Jun 23, 8:23 am, "jim beam" (who?) anonymously snipes:
>>>> Tim McNamara wrote:
>>>>> "jim beam" (who?) anonymously snipes:
>>>>>> Tim McNamara wrote:
>>>>>>> Mike Jacoubowskywrote:
>>>>>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>>>>>> descending this one particular road when there was a crosswind
>>>>>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
>>>>>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>>>>> coincident.
>>>>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>>>>> disagree with this?
>>>>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>>>>> angle's intersection with the road, yes it is inherently stable.
>>>>>>>> So you could give the bike a push, without a rider on it, and it
>>>>>>>> would go exactly how far before falling over?
>>>>>>>> in that the
>>>>>>>>> spring constants of both frame and tires give resonant
>>>>>>>>> frequencies well above any frequency that can gain any
>>>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>>>>>> you're working with incomplete information.
>>>>>>>> What information did I leave out?
>>>>>>> You don't have jim's apperceptive mass. He can see subtle reasons
>>>>>>> for these phenomena that are obscure to the rest of us mere
>>>>>>> mortals.
>>>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>>>> retards.
>>>>> Well, obscure to you anyway.
>>>>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>>>>> shop owner for the past 30 years or so.
>>>>>> with all due respect to bike store owners, 30 years on the job
>>>>>> doesn't automatically make them scientists expert in analysis of this
>>>>>> kind of problem. just like window frame fitters turned psychologists
>>>>>> aren't automatically good at the most basic of math concepts.
>>>>> That's "glazier" to you. :-) Of course, by the same token
>>>>> metallurgists aren't automatically good at mechanical engineering- as
>>>>> the mechanical engineers have been pointing out to you for years.
>>>> funny. like it took a metallurgist to point out that the tensiometer
>>>> math in "the book" had omitted spoke stiffness - that's supposed to be
>>>> "mechanical engineering". but you'd already spotted that error hadn't
>>>> you timmy - you were just waiting for the right time to say something.
>>>>>>>>>> Are you suggesting that a shaking rider should have no effect on
>>>>>>>>>> a bike's resistance to shimmy?
>>>>>>>>> the rider should not be able to make the bike shimmy. with rider
>>>>>>>>> load, the resonance of the frame and of the wheels should not be
>>>>>>>>> coincident. period. many old fashioned steel frames /do/ shimmy
>>>>>>>>> because their torsional stiffness is not very high, and in the
>>>>>>>>> old days of undished wheels, it wasn't as much of a problem, but
>>>>>>>>> now, with 10-speed ultra-dished wheels, it's a big deal. if we
>>>>>>>>> can't have un-dished wheels, we can have torsionally stiff frames
>>>>>>>>> where their designer has paid attention to this stuff. no
>>>>>>>>> excuses.
>>>>>>>> So you believe flimsy wheels are the culprit? I used to think so
>>>>>>>> too. But after changing out wheels (lighter wheels exchanged for
>>>>>>>> much-beefier, stiffer versions) for a number of people, without
>>>>>>>> cure, that didn't appear to be the answer. I had much better
>>>>>>>> success by changing the position of the handlebars.
>>>>>>>> That's not to say that large frames aren't far more prone to
>>>>>>>> shimmy than smaller ones. You're absolutely correct about that.
>>>>>>>> But that wasn't the issue for the particular case I referenced. I
>>>>>>>> didn't include the frame size; it was 56cm, center-to-top.
>>>>>>>> Oops, I left out one other piece of information. The person whose
>>>>>>>> bike shimmied that I mentioned also had to take one hand off the
>>>>>>>> bars for the shimmy to occur. So you've got *5* things that had to
>>>>>>>> exist for her bike to shimmy-
>>>>>>>> #1: Only on this one particular road #2: Speed had to be 38mph #3:
>>>>>>>> One hand off the bars #4: Crosswind #5: Cold
>>>>>>>> So think about what I'm saying here. If it was warm, no shimmy.
>>>>>>>> Hands on bars, no shimmy. Any other road, including descents at
>>>>>>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind,
>>>>>>>> no shimmy. For the sake of full disclosure, the only thing
>>>>>>>> possibly unusual about this one stretch of road is that it's
>>>>>>>> perfectly straight for a fairly good distance. I think that pretty
>>>>>>>> much lays everything out on the table.
>>>>>>>> Still think it was a problem with the bike? (And yes, we did try
>>>>>>>> different wheels. She wouldn't consider changing her position on
>>>>>>>> the bike, so we couldn't test for that.)
>>>>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
>>>>>>> Expert) and that if he says the problem is that the rear wheel is
>>>>>>> too flexible, then that's the problem. If you replace the rear
>>>>>>> wheel with a stiffer wheel and the bike still shimmies, jim is
>>>>>>> still right- it's reality that's wrong.
>>>>>> how would you know? you think i'm lying when i say that 5000 > 1600,
>>>>>> so everything is bullshit to you. retard.
>>>>> You're lying again, jim, just like you were back in that thread. You
>>>>> keep coming up with different numbers- obviously you don't get the same
>>>>> answer consistently when you add 2 + 2. I doubt your mathematics
>>>>> abilities more and more. Or perhaps it's your memory.
>>>> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
>>>> you're an irredeemable fucking retard timmy!
>>>> ***
>>>> dear mrs mcnamara
>>>> it is with regret that we must tell you to keep your son home for
>>>> another week's suspension again this semester. he has been fighting
>>>> with the other boys and is becoming increasingly disruptive in class.
>>>> in addition, as discussed at our last meeting, his grades continue to be
>>>> well below standard, and even with the remedial classes he's been
>>>> attending, he has shown no ability to catch up.
>>>> in consultation with his teachers and the school counselor therefore, it
>>>> is our opinion that academic frustration and taunting from the other
>>>> children are causing his behavior problems. in timmy's best interests
>>>> therefore, we will will be making arrangements for him to attend happy
>>>> valley retards school where his special needs can be better
>>>> accommodated. you will be contacted directly by happy valley's
>>>> admissions director, ms. u. gottabekiddingme, ph.d., and their learning
>>>> difficulties specialist, dr. i. v. ritalin, who will be supervising his
>>>> treatments.
>>> FEEL THE LOVE!
>>> I wonder if "jim beam" would be so ready to snipe if he/she had to use
>>> his/her real name on the postings?
>> sure. utter bullshit doesn't need a nom-de-net.
>
> Then why use one?
because i want to!
> Who or what are you afraid of?
>
er, you?
but that's not the point. reality is, handle has NOTHING to do with
accuracy. the ridiculous way things are hereabouts,
http://www.theflatearthsociety.org/ would be given credence on r.b.t if
they told you they were were stanford alumni.
|
| | | |
Date: 23 Jun 2007 15:39:16
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
> but that's not the point. reality is, handle has NOTHING to do with
> accuracy. the ridiculous way things are hereabouts,
I just wanted to let that viewpoint air itself out on the 'net a bit more.
It's one of the more-puzzling things I see people write.
I should add that a "handle" doesn't necessarily mean something is less
accurate, but rather that accountability, and thus credibility, is greatly
reduced. Not eliminated, mind you, but very much reduced. In my humble
opinion anyway.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| |
Date: 23 Jun 2007 11:35:08
From: Gary Young
Subject: Re: High Speed Shimmy
|
On Sat, 23 Jun 2007 08:12:24 -0700, jim beam wrote:
> Gary Young wrote:
>> On Sat, 23 Jun 2007 06:23:15 -0700, jim beam wrote:
>>
>>> Tim McNamara wrote:
>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>
>>>>> Tim McNamara wrote:
>>>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>>
>>>>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>>>>> descending this one particular road when there was a crosswind
>>>>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
>>>>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>>>> coincident.
>>>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>>>> disagree with this?
>>>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>>>> angle's intersection with the road, yes it is inherently stable.
>>>>>>> So you could give the bike a push, without a rider on it, and it
>>>>>>> would go exactly how far before falling over?
>>>>>>>
>>>>>>> in that the
>>>>>>>> spring constants of both frame and tires give resonant
>>>>>>>> frequencies well above any frequency that can gain any
>>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>>
>>>>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>>>>> you're working with incomplete information.
>>>>>>> What information did I leave out?
>>>>>> You don't have jim's apperceptive mass. He can see subtle reasons
>>>>>> for these phenomena that are obscure to the rest of us mere
>>>>>> mortals.
>>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>>> retards.
>>>> Well, obscure to you anyway.
>>>>
>>>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>>>> shop owner for the past 30 years or so.
>>>>> with all due respect to bike store owners, 30 years on the job
>>>>> doesn't automatically make them scientists expert in analysis of
>>>>> this kind of problem. just like window frame fitters turned
>>>>> psychologists aren't automatically good at the most basic of math
>>>>> concepts.
>>>> That's "glazier" to you. :-) Of course, by the same token
>>>> metallurgists aren't automatically good at mechanical engineering- as
>>>> the mechanical engineers have been pointing out to you for years.
>>> funny. like it took a metallurgist to point out that the tensiometer
>>> math in "the book" had omitted spoke stiffness - that's supposed to be
>>> "mechanical engineering".
>>
>> First of all, you're not a metallurgist, ex or otherwise.
>
> interesting - you can't possibly /know/ that unless you've researched my
> academic record, and how are you going to do that???
It's a reasonable conclusion based on the available evidence, e.g., your
refusal to state what your credentials are, your childish mode of
argumentation, and the many boneheaded mistakes you've made over the
years.
> just imagine for a
> moment that you're wrong - then what are you going to say???
>
>
I would have to revise my opinion and say that you are an incompetent
metallurgist.
>> Secondly, the
>> omission of spoke stiffness from Jobst's equations had been discussed
>> on rbt long before you made an appearance here.
>
> google doesn't agree with you on that.
>
>
http://yarchive.net/bike/tensiometer.html
There are a few posts archived at that site where Jobst makes it clear
that he thought spoke thickness could be ignored because it didn't produce
significant differences in results over the normal range of spoke gauges.
In the first post, for instance, he says, "bending stiffness over a 100mm
span is small enough to make the difference between 1.6 and 2.0mm diameter
spokes insignificant."
>> What was required was
>> calculations showing that the omission was significant and that was
>> supplied by Joe Rial (and perhaps Luns Tee) and not you.
>
> riel - get with the google gary.
>
> you're right that i didn't contribute calculations. but i pointed out
> the deficiency. and i see nobody in the archive that did it prior.
> prove me wrong if you have this belief.
>
>
See above. Jobst had already pointed out why he deliberately left spoke
thickness out of the picture (when using his tensiometer). He may have
been mistaken about the magnitude of changes instroduced by thickness
variations within the usual range of spoke gauges, but it can't be said
that he was unaware of the need to take into account spoke thickness as a
general matter (for instance, when variations fall outside the usual range
of gauges).
> [i'd love your commentary on exactly how this omission has stood
> unchallenged since "the book" was first published too while you're at
> it.]
>
>
>
I can only guess, but a likely explanation is that no one had bothered to
do the calculations until Joe Riel.
>> In fact, when it
>> comes time to present actual equations, you usually beg off.
>
> sure! why bother when you're just an anonymous troll with no academic
> credentials? nobody reads this stuff anyway. i simply can't imagine
> why you do.
>
>
>
Is there a point buried in there?
>
|
| |
Date: 23 Jun 2007 09:22:31
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 23, 10:12 am, "jim beam" (who?) anonymously snipes wrote:
> Gary Young wrote:
> ...
> > First of all, you're not a metallurgist, ex or otherwise....
>
> interesting - you can't possibly /know/ that unless you've researched my
> academic record, and how are you going to do that??? just imagine for a
> moment that you're wrong - then what are you going to say???...
Put your real record out there for inspection, bourbon man!
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| |
Date: 23 Jun 2007 09:38:06
From: Gary Young
Subject: Re: High Speed Shimmy
|
On Sat, 23 Jun 2007 06:23:15 -0700, jim beam wrote:
> Tim McNamara wrote:
>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>> jim beam <spamvortex@bad.example.net> wrote:
>>
>>> Tim McNamara wrote:
>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>
>>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>>> descending this one particular road when there was a crosswind
>>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
>>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>> coincident.
>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>> disagree with this?
>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>> angle's intersection with the road, yes it is inherently stable.
>>>>> So you could give the bike a push, without a rider on it, and it
>>>>> would go exactly how far before falling over?
>>>>>
>>>>> in that the
>>>>>> spring constants of both frame and tires give resonant
>>>>>> frequencies well above any frequency that can gain any
>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>
>>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>>> you're working with incomplete information.
>>>>> What information did I leave out?
>>>> You don't have jim's apperceptive mass. He can see subtle reasons
>>>> for these phenomena that are obscure to the rest of us mere
>>>> mortals.
>>> one thing's for sure: there's a helluva lot that's obscure to
>>> retards.
>>
>> Well, obscure to you anyway.
>>
>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>> shop owner for the past 30 years or so.
>>> with all due respect to bike store owners, 30 years on the job
>>> doesn't automatically make them scientists expert in analysis of this
>>> kind of problem. just like window frame fitters turned psychologists
>>> aren't automatically good at the most basic of math concepts.
>>
>> That's "glazier" to you. :-) Of course, by the same token
>> metallurgists aren't automatically good at mechanical engineering- as
>> the mechanical engineers have been pointing out to you for years.
>
> funny. like it took a metallurgist to point out that the tensiometer
> math in "the book" had omitted spoke stiffness - that's supposed to be
> "mechanical engineering".
First of all, you're not a metallurgist, ex or otherwise. Secondly, the
omission of spoke stiffness from Jobst's equations had been discussed on
rbt long before you made an appearance here. What was required was
calculations showing that the omission was significant and that was
supplied by Joe Rial (and perhaps Luns Tee) and not you. In fact, when it
comes time to present actual equations, you usually beg off.
> but you'd already spotted that error hadn't
> you timmy - you were just waiting for the right time to say something.
>
>
>>>>>>> Are you suggesting that a shaking rider should have no effect on a
>>>>>>> bike's resistance to shimmy?
>>>>>> the rider should not be able to make the bike shimmy. with rider
>>>>>> load, the resonance of the frame and of the wheels should not be
>>>>>> coincident. period. many old fashioned steel frames /do/ shimmy
>>>>>> because their torsional stiffness is not very high, and in the old
>>>>>> days of undished wheels, it wasn't as much of a problem, but now,
>>>>>> with 10-speed ultra-dished wheels, it's a big deal. if we can't
>>>>>> have un-dished wheels, we can have torsionally stiff frames where
>>>>>> their designer has paid attention to this stuff. no excuses.
>>>>> So you believe flimsy wheels are the culprit? I used to think so
>>>>> too. But after changing out wheels (lighter wheels exchanged for
>>>>> much-beefier, stiffer versions) for a number of people, without
>>>>> cure, that didn't appear to be the answer. I had much better success
>>>>> by changing the position of the handlebars.
>>>>>
>>>>> That's not to say that large frames aren't far more prone to shimmy
>>>>> than smaller ones. You're absolutely correct about that. But that
>>>>> wasn't the issue for the particular case I referenced. I didn't
>>>>> include the frame size; it was 56cm, center-to-top.
>>>>>
>>>>> Oops, I left out one other piece of information. The person whose
>>>>> bike shimmied that I mentioned also had to take one hand off the
>>>>> bars for the shimmy to occur. So you've got *5* things that had to
>>>>> exist for her bike to shimmy-
>>>>> #1: Only on this one particular road #2: Speed had to be 38mph #3:
>>>>> One hand off the bars #4: Crosswind #5: Cold
>>>>>
>>>>> So think about what I'm saying here. If it was warm, no shimmy.
>>>>> Hands on bars, no shimmy. Any other road, including descents at
>>>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind, no
>>>>> shimmy. For the sake of full disclosure, the only thing possibly
>>>>> unusual about this one stretch of road is that it's perfectly
>>>>> straight for a fairly good distance. I think that pretty much lays
>>>>> everything out on the table.
>>>>>
>>>>> Still think it was a problem with the bike? (And yes, we did try
>>>>> different wheels. She wouldn't consider changing her position on the
>>>>> bike, so we couldn't test for that.)
>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
>>>> Expert) and that if he says the problem is that the rear wheel is too
>>>> flexible, then that's the problem. If you replace the rear wheel
>>>> with a stiffer wheel and the bike still shimmies, jim is still right-
>>>> it's reality that's wrong.
>>> how would you know? you think i'm lying when i say that 5000 > 1600,
>>> so everything is bullshit to you. retard.
>>
>> You're lying again, jim, just like you were back in that thread. You
>> keep coming up with different numbers- obviously you don't get the same
>> answer consistently when you add 2 + 2. I doubt your mathematics
>> abilities more and more. Or perhaps it's your memory.
>
> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
> you're an irredeemable fucking retard timmy!
>
>
>
> ***
>
> dear mrs mcnamara
>
> it is with regret that we must tell you to keep your son home for
> another week's suspension again this semester. he has been fighting
> with the other boys and is becoming increasingly disruptive in class. in
> addition, as discussed at our last meeting, his grades continue to be
> well below standard, and even with the remedial classes he's been
> attending, he has shown no ability to catch up.
>
> in consultation with his teachers and the school counselor therefore, it
> is our opinion that academic frustration and taunting from the other
> children are causing his behavior problems. in timmy's best interests
> therefore, we will will be making arrangements for him to attend happy
> valley retards school where his special needs can be better
> accommodated. you will be contacted directly by happy valley's
> admissions director, ms. u. gottabekiddingme, ph.d., and their learning
> difficulties specialist, dr. i. v. ritalin, who will be supervising his
> treatments.
|
| | |
Date: 23 Jun 2007 08:12:24
From: jim beam
Subject: Re: High Speed Shimmy
|
Gary Young wrote:
> On Sat, 23 Jun 2007 06:23:15 -0700, jim beam wrote:
>
>> Tim McNamara wrote:
>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>
>>>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>>>> descending this one particular road when there was a crosswind
>>>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
>>>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>>> coincident.
>>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>>> disagree with this?
>>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>>> angle's intersection with the road, yes it is inherently stable.
>>>>>> So you could give the bike a push, without a rider on it, and it
>>>>>> would go exactly how far before falling over?
>>>>>>
>>>>>> in that the
>>>>>>> spring constants of both frame and tires give resonant
>>>>>>> frequencies well above any frequency that can gain any
>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>
>>>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>>>> you're working with incomplete information.
>>>>>> What information did I leave out?
>>>>> You don't have jim's apperceptive mass. He can see subtle reasons
>>>>> for these phenomena that are obscure to the rest of us mere
>>>>> mortals.
>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>> retards.
>>> Well, obscure to you anyway.
>>>
>>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>>> shop owner for the past 30 years or so.
>>>> with all due respect to bike store owners, 30 years on the job
>>>> doesn't automatically make them scientists expert in analysis of this
>>>> kind of problem. just like window frame fitters turned psychologists
>>>> aren't automatically good at the most basic of math concepts.
>>> That's "glazier" to you. :-) Of course, by the same token
>>> metallurgists aren't automatically good at mechanical engineering- as
>>> the mechanical engineers have been pointing out to you for years.
>> funny. like it took a metallurgist to point out that the tensiometer
>> math in "the book" had omitted spoke stiffness - that's supposed to be
>> "mechanical engineering".
>
> First of all, you're not a metallurgist, ex or otherwise.
interesting - you can't possibly /know/ that unless you've researched my
academic record, and how are you going to do that??? just imagine for a
moment that you're wrong - then what are you going to say???
> Secondly, the
> omission of spoke stiffness from Jobst's equations had been discussed on
> rbt long before you made an appearance here.
google doesn't agree with you on that.
> What was required was
> calculations showing that the omission was significant and that was
> supplied by Joe Rial (and perhaps Luns Tee) and not you.
riel - get with the google gary.
you're right that i didn't contribute calculations. but i pointed out
the deficiency. and i see nobody in the archive that did it prior.
prove me wrong if you have this belief.
[i'd love your commentary on exactly how this omission has stood
unchallenged since "the book" was first published too while you're at it.]
> In fact, when it
> comes time to present actual equations, you usually beg off.
sure! why bother when you're just an anonymous troll with no academic
credentials? nobody reads this stuff anyway. i simply can't imagine
why you do.
<snip remaining >
|
| |
Date: 23 Jun 2007 06:52:50
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 23, 8:23 am, "jim beam" (who?) anonymously snipes:
> Tim McNamara wrote:
> > "jim beam" (who?) anonymously snipes:
>
> >> Tim McNamara wrote:
> >>> Mike Jacoubowskywrote:
>
> >>>>>>>> This comes up so often at my end of the business. We had one
> >>>>>>>> person who was terrified there was something very wrong with
> >>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
> >>>>>>>> descending this one particular road when there was a crosswind
> >>>>>>>> on a cold day. *All* those things had to exist for the shimmy
> >>>>>>>> to occur. And yet it was the bike at fault.
> >>>>>>> it is. bike shouldn't do it under any circumstances. the
> >>>>>>> resonance of the frame and wheels should be different, not
> >>>>>>> coincident.
> >>>>>> A bike is not stable without a rider on it. Do you actually
> >>>>>> disagree with this?
> >>>>> in that the contact patch of the tire trails behind the fork
> >>>>> angle's intersection with the road, yes it is inherently stable.
> >>>> So you could give the bike a push, without a rider on it, and it
> >>>> would go exactly how far before falling over?
>
> >>>> in that the
> >>>>> spring constants of both frame and tires give resonant
> >>>>> frequencies well above any frequency that can gain any
> >>>>> significant amplitude, yes, it is inherently stable.
>
> >>>>>> And, if you don't, do you understand the ramifications of it?
> >>>>> you're working with incomplete information.
> >>>> What information did I leave out?
> >>> You don't have jim's apperceptive mass. He can see subtle reasons
> >>> for these phenomena that are obscure to the rest of us mere
> >>> mortals.
> >> one thing's for sure: there's a helluva lot that's obscure to
> >> retards.
>
> > Well, obscure to you anyway.
>
> >>> You see, jim was a metallurgist whereas you've only been a bike
> >>> shop owner for the past 30 years or so.
> >> with all due respect to bike store owners, 30 years on the job
> >> doesn't automatically make them scientists expert in analysis of this
> >> kind of problem. just like window frame fitters turned psychologists
> >> aren't automatically good at the most basic of math concepts.
>
> > That's "glazier" to you. :-) Of course, by the same token
> > metallurgists aren't automatically good at mechanical engineering- as
> > the mechanical engineers have been pointing out to you for years.
>
> funny. like it took a metallurgist to point out that the tensiometer
> math in "the book" had omitted spoke stiffness - that's supposed to be
> "mechanical engineering". but you'd already spotted that error hadn't
> you timmy - you were just waiting for the right time to say something.
>
>
>
>
>
> >>>>>> Are you suggesting that a shaking rider should have no effect on
> >>>>>> a bike's resistance to shimmy?
> >>>>> the rider should not be able to make the bike shimmy. with rider
> >>>>> load, the resonance of the frame and of the wheels should not be
> >>>>> coincident. period. many old fashioned steel frames /do/ shimmy
> >>>>> because their torsional stiffness is not very high, and in the
> >>>>> old days of undished wheels, it wasn't as much of a problem, but
> >>>>> now, with 10-speed ultra-dished wheels, it's a big deal. if we
> >>>>> can't have un-dished wheels, we can have torsionally stiff frames
> >>>>> where their designer has paid attention to this stuff. no
> >>>>> excuses.
> >>>> So you believe flimsy wheels are the culprit? I used to think so
> >>>> too. But after changing out wheels (lighter wheels exchanged for
> >>>> much-beefier, stiffer versions) for a number of people, without
> >>>> cure, that didn't appear to be the answer. I had much better
> >>>> success by changing the position of the handlebars.
>
> >>>> That's not to say that large frames aren't far more prone to
> >>>> shimmy than smaller ones. You're absolutely correct about that.
> >>>> But that wasn't the issue for the particular case I referenced. I
> >>>> didn't include the frame size; it was 56cm, center-to-top.
>
> >>>> Oops, I left out one other piece of information. The person whose
> >>>> bike shimmied that I mentioned also had to take one hand off the
> >>>> bars for the shimmy to occur. So you've got *5* things that had to
> >>>> exist for her bike to shimmy-
> >>>> #1: Only on this one particular road #2: Speed had to be 38mph #3:
> >>>> One hand off the bars #4: Crosswind #5: Cold
>
> >>>> So think about what I'm saying here. If it was warm, no shimmy.
> >>>> Hands on bars, no shimmy. Any other road, including descents at
> >>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind,
> >>>> no shimmy. For the sake of full disclosure, the only thing
> >>>> possibly unusual about this one stretch of road is that it's
> >>>> perfectly straight for a fairly good distance. I think that pretty
> >>>> much lays everything out on the table.
>
> >>>> Still think it was a problem with the bike? (And yes, we did try
> >>>> different wheels. She wouldn't consider changing her position on
> >>>> the bike, so we couldn't test for that.)
> >>> Now, Mike, you know that jim is the infallible APE (All Purpose
> >>> Expert) and that if he says the problem is that the rear wheel is
> >>> too flexible, then that's the problem. If you replace the rear
> >>> wheel with a stiffer wheel and the bike still shimmies, jim is
> >>> still right- it's reality that's wrong.
> >> how would you know? you think i'm lying when i say that 5000 > 1600,
> >> so everything is bullshit to you. retard.
>
> > You're lying again, jim, just like you were back in that thread. You
> > keep coming up with different numbers- obviously you don't get the same
> > answer consistently when you add 2 + 2. I doubt your mathematics
> > abilities more and more. Or perhaps it's your memory.
>
> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
> you're an irredeemable fucking retard timmy!
>
> ***
>
> dear mrs mcnamara
>
> it is with regret that we must tell you to keep your son home for
> another week's suspension again this semester. he has been fighting
> with the other boys and is becoming increasingly disruptive in class.
> in addition, as discussed at our last meeting, his grades continue to be
> well below standard, and even with the remedial classes he's been
> attending, he has shown no ability to catch up.
>
> in consultation with his teachers and the school counselor therefore, it
> is our opinion that academic frustration and taunting from the other
> children are causing his behavior problems. in timmy's best interests
> therefore, we will will be making arrangements for him to attend happy
> valley retards school where his special needs can be better
> accommodated. you will be contacted directly by happy valley's
> admissions director, ms. u. gottabekiddingme, ph.d., and their learning
> difficulties specialist, dr. i. v. ritalin, who will be supervising his
> treatments.
FEEL THE LOVE!
I wonder if "jim beam" would be so ready to snipe if he/she had to use
his/her real name on the postings?
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | |
Date: 23 Jun 2007 06:55:26
From: jim beam
Subject: Re: High Speed Shimmy
|
Johnny Sunset wrote:
> On Jun 23, 8:23 am, "jim beam" (who?) anonymously snipes:
>> Tim McNamara wrote:
>>> "jim beam" (who?) anonymously snipes:
>>>> Tim McNamara wrote:
>>>>> Mike Jacoubowskywrote:
>>>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>>>> descending this one particular road when there was a crosswind
>>>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
>>>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>>> coincident.
>>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>>> disagree with this?
>>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>>> angle's intersection with the road, yes it is inherently stable.
>>>>>> So you could give the bike a push, without a rider on it, and it
>>>>>> would go exactly how far before falling over?
>>>>>> in that the
>>>>>>> spring constants of both frame and tires give resonant
>>>>>>> frequencies well above any frequency that can gain any
>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>>>> you're working with incomplete information.
>>>>>> What information did I leave out?
>>>>> You don't have jim's apperceptive mass. He can see subtle reasons
>>>>> for these phenomena that are obscure to the rest of us mere
>>>>> mortals.
>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>> retards.
>>> Well, obscure to you anyway.
>>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>>> shop owner for the past 30 years or so.
>>>> with all due respect to bike store owners, 30 years on the job
>>>> doesn't automatically make them scientists expert in analysis of this
>>>> kind of problem. just like window frame fitters turned psychologists
>>>> aren't automatically good at the most basic of math concepts.
>>> That's "glazier" to you. :-) Of course, by the same token
>>> metallurgists aren't automatically good at mechanical engineering- as
>>> the mechanical engineers have been pointing out to you for years.
>> funny. like it took a metallurgist to point out that the tensiometer
>> math in "the book" had omitted spoke stiffness - that's supposed to be
>> "mechanical engineering". but you'd already spotted that error hadn't
>> you timmy - you were just waiting for the right time to say something.
>>
>>
>>
>>
>>
>>>>>>>> Are you suggesting that a shaking rider should have no effect on
>>>>>>>> a bike's resistance to shimmy?
>>>>>>> the rider should not be able to make the bike shimmy. with rider
>>>>>>> load, the resonance of the frame and of the wheels should not be
>>>>>>> coincident. period. many old fashioned steel frames /do/ shimmy
>>>>>>> because their torsional stiffness is not very high, and in the
>>>>>>> old days of undished wheels, it wasn't as much of a problem, but
>>>>>>> now, with 10-speed ultra-dished wheels, it's a big deal. if we
>>>>>>> can't have un-dished wheels, we can have torsionally stiff frames
>>>>>>> where their designer has paid attention to this stuff. no
>>>>>>> excuses.
>>>>>> So you believe flimsy wheels are the culprit? I used to think so
>>>>>> too. But after changing out wheels (lighter wheels exchanged for
>>>>>> much-beefier, stiffer versions) for a number of people, without
>>>>>> cure, that didn't appear to be the answer. I had much better
>>>>>> success by changing the position of the handlebars.
>>>>>> That's not to say that large frames aren't far more prone to
>>>>>> shimmy than smaller ones. You're absolutely correct about that.
>>>>>> But that wasn't the issue for the particular case I referenced. I
>>>>>> didn't include the frame size; it was 56cm, center-to-top.
>>>>>> Oops, I left out one other piece of information. The person whose
>>>>>> bike shimmied that I mentioned also had to take one hand off the
>>>>>> bars for the shimmy to occur. So you've got *5* things that had to
>>>>>> exist for her bike to shimmy-
>>>>>> #1: Only on this one particular road #2: Speed had to be 38mph #3:
>>>>>> One hand off the bars #4: Crosswind #5: Cold
>>>>>> So think about what I'm saying here. If it was warm, no shimmy.
>>>>>> Hands on bars, no shimmy. Any other road, including descents at
>>>>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind,
>>>>>> no shimmy. For the sake of full disclosure, the only thing
>>>>>> possibly unusual about this one stretch of road is that it's
>>>>>> perfectly straight for a fairly good distance. I think that pretty
>>>>>> much lays everything out on the table.
>>>>>> Still think it was a problem with the bike? (And yes, we did try
>>>>>> different wheels. She wouldn't consider changing her position on
>>>>>> the bike, so we couldn't test for that.)
>>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
>>>>> Expert) and that if he says the problem is that the rear wheel is
>>>>> too flexible, then that's the problem. If you replace the rear
>>>>> wheel with a stiffer wheel and the bike still shimmies, jim is
>>>>> still right- it's reality that's wrong.
>>>> how would you know? you think i'm lying when i say that 5000 > 1600,
>>>> so everything is bullshit to you. retard.
>>> You're lying again, jim, just like you were back in that thread. You
>>> keep coming up with different numbers- obviously you don't get the same
>>> answer consistently when you add 2 + 2. I doubt your mathematics
>>> abilities more and more. Or perhaps it's your memory.
>> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
>> you're an irredeemable fucking retard timmy!
>>
>> ***
>>
>> dear mrs mcnamara
>>
>> it is with regret that we must tell you to keep your son home for
>> another week's suspension again this semester. he has been fighting
>> with the other boys and is becoming increasingly disruptive in class.
>> in addition, as discussed at our last meeting, his grades continue to be
>> well below standard, and even with the remedial classes he's been
>> attending, he has shown no ability to catch up.
>>
>> in consultation with his teachers and the school counselor therefore, it
>> is our opinion that academic frustration and taunting from the other
>> children are causing his behavior problems. in timmy's best interests
>> therefore, we will will be making arrangements for him to attend happy
>> valley retards school where his special needs can be better
>> accommodated. you will be contacted directly by happy valley's
>> admissions director, ms. u. gottabekiddingme, ph.d., and their learning
>> difficulties specialist, dr. i. v. ritalin, who will be supervising his
>> treatments.
>
> FEEL THE LOVE!
>
> I wonder if "jim beam" would be so ready to snipe if he/she had to use
> his/her real name on the postings?
>
>
sure. utter bullshit doesn't need a nom-de-net.
|
| |
Date: 23 Jun 2007 02:36:26
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 22, 10:24 pm, datakoll <datak...@yahoo.com > wrote:
> On Jun 22, 10:08 pm, jobst.bra...@stanfordalumni.org wrote:
>
>
>
>
>
> > Gene Daniels writes:
> > > Try adding a weight, start with say 5-8lbs, to the top tube. slide
> > > weight forward. does shimmy stop?
> > > Experiment tends to indicate a general looseness in the mechanism
> > > from contact surface to headset possibly as noted preceding back to
> > > rear hub looseness in complementary and additive hinge effects. that
> > > is, the wheel may be balanced and true yet shimmy occurs.
>
> > That isn't what I discovered in pursuing causes of shimmy. I filled
> > the front tire (entirely) with water without any effect. I tried Rolf
> > Vector Pro and Bontrager paired spoked wheels that had no effect.
>
> > Damon Rinard repeated that experiment and found the same results, only
> > that he instrumented the bicycle with an accelerometer on the head
> > tube (the part of the bicycle that actually shimmies) and found the
> > paired spoke wheels and a 36 spoke standard wheel had the same shimmy
> > frequency, proving That shimmy is developed by the frame. These were
> > all no-hands tests on a smooth descent, the same as the one I did.
>
> >http://www.sheldonbrown.com/brandt/shimmy.html
>
> > Jobst Brandt
>
> weight came into the picture thru using the top tube to carry
> distilled water in gallon jugs on a rope balanced over the top tube.
> back from the store or to work. i commuted over the causeway.
> the front wheel was used, worn hub and cones. needed tightening or
> replacement. but was in balance and true.
> so one day down the slope the shimmy devil attacked once twice then i
> thought to load the front by moving the jugs up to top tube's front
> and the shimmy stopped. off course, the top tube weight doesn't
> revolve.
> i tightened the hub/axle/cones and the shimmy stopped without weight
> but was elliptical and loosened.
> so get a grip and lean forward, move yourweight onto the front fork.
> a new bike may need-breaking in-to eliminate the out of synch
> vibrations that cause a shimmy anamoly?- Hide quoted text -
>
> - Show quoted text -
i see what your up to here? -the cause beyond curing the shimmy is not
reducing the mechanism's looseness with the weight going forward-
so i assume that as an engineer you know mathmatically that adding
weight to a loose revolving mechanism cannot force it into a more
precise and more balanced race action?
but that would run counter to the idea of adequate torque to place the
bearing/axle structure into correct design functions. or loose wheels
wobble more than correctly tightened wheels
okokok torque is not top loading but top loading does press the
bearing surfaces down into their working areas which-i assume-limits
the excess movement.
group 2
|
| |
Date: 23 Jun 2007 02:24:25
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 22, 10:08 pm, jobst.bra...@stanfordalumni.org wrote:
> Gene Daniels writes:
> > Try adding a weight, start with say 5-8lbs, to the top tube. slide
> > weight forward. does shimmy stop?
> > Experiment tends to indicate a general looseness in the mechanism
> > from contact surface to headset possibly as noted preceding back to
> > rear hub looseness in complementary and additive hinge effects. that
> > is, the wheel may be balanced and true yet shimmy occurs.
>
> That isn't what I discovered in pursuing causes of shimmy. I filled
> the front tire (entirely) with water without any effect. I tried Rolf
> Vector Pro and Bontrager paired spoked wheels that had no effect.
>
> Damon Rinard repeated that experiment and found the same results, only
> that he instrumented the bicycle with an accelerometer on the head
> tube (the part of the bicycle that actually shimmies) and found the
> paired spoke wheels and a 36 spoke standard wheel had the same shimmy
> frequency, proving That shimmy is developed by the frame. These were
> all no-hands tests on a smooth descent, the same as the one I did.
>
> http://www.sheldonbrown.com/brandt/shimmy.html
>
> Jobst Brandt
weight came into the picture thru using the top tube to carry
distilled water in gallon jugs on a rope balanced over the top tube.
back from the store or to work. i commuted over the causeway.
the front wheel was used, worn hub and cones. needed tightening or
replacement. but was in balance and true.
so one day down the slope the shimmy devil attacked once twice then i
thought to load the front by moving the jugs up to top tube's front
and the shimmy stopped. off course, the top tube weight doesn't
revolve.
i tightened the hub/axle/cones and the shimmy stopped without weight
but was elliptical and loosened.
so get a grip and lean forward, move yourweight onto the front fork.
a new bike may need-breaking in-to eliminate the out of synch
vibrations that cause a shimmy anamoly?
|
| | |
Date: 23 Jun 2007 18:48:43
From:
Subject: Re: High Speed Shimmy
|
Gene Daniels writes:
>>> Try adding a weight, start with say 5-8lbs, to the top tube. slide
>>> weight forward. does shimmy stop?
>>> Experiment tends to indicate a general looseness in the mechanism
>>> from contact surface to headset possibly as noted preceding back to
>>> rear hub looseness in complementary and additive hinge effects. that
>>> is, the wheel may be balanced and true yet shimmy occurs.
>> That isn't what I discovered in pursuing causes of shimmy. I filled
>> the front tire (entirely) with water without any effect. I tried Rolf
>> Vector Pro and Bontrager paired spoked wheels that had no effect.
>> Damon Rinard repeated that experiment and found the same results, only
>> that he instrumented the bicycle with an accelerometer on the head
>> tube (the part of the bicycle that actually shimmies) and found the
>> paired spoke wheels and a 36 spoke standard wheel had the same shimmy
>> frequency, proving That shimmy is developed by the frame. These were
>> all no-hands tests on a smooth descent, the same as the one I did.
http://www.sheldonbrown.com/brandt/shimmy.html
> Weight came into the picture thru using the top tube to carry
> distilled water in gallon jugs on a rope balanced over the top tube.
> back from the store or to work. I commuted over the causeway. the
> front wheel was used, worn hub and cones. needed tightening or
> replacement. but was in balance and true.
You have too many variables to discern what causes shimmy.
> So one day down the slope the shimmy devil attacked once twice then
> I thought to load the front by moving the jugs up to top tube's
> front and the shimmy stopped. Of course, the top tube weight
> doesn't revolve.
Don't overlook that jugs of water are dampers, the fluid being movable
and sensitive to angular motion even if there is no air in the
container that would allow it to slosh.
> I tightened the hub/axle/cones and the shimmy stopped without weight
> but was elliptical and loosened.
I have found no correlation between bearing adjustment and shimmy.
This is an elastic-dynamic response that would require large bearing
clearance to abate by itself. Lack of clearance only enhances shimmy.
Damping is the solution and that can be offered by hands on the bars.
> So get a grip and lean forward, move your weight onto the front fork.
> A new bike may need-breaking in-to eliminate the out of synch
> vibrations that cause a shimmy anamoly?
Ooh! Explain what that means. Are you suggesting that steel frames
get soft with use and age, for instance?
Jobst Brandt
|
| |
Date: 23 Jun 2007 02:14:11
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 22, 12:02 pm, "Tom Nakashima" <t...@slac.stanford.edu > wrote:
> "Tim McNamara" <tim...@bitstream.net> wrote in message
>
> news:timmcn-13AF48.10392722062007@news.iphouse.com...
>
> > In article <f5gnqe$j6...@news.Stanford.EDU>,
> > "Tom Nakashima" <t...@slac.stanford.edu> wrote:
>
> >> Animation of shimmy
>
> >> Animation of death wobble
>
> > Ummm. Huh?
>
> Links:
> Animation of shimmy:http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.avi
>
> Animation of death wobble:http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/weave_0_65.avi
>
> Not sure why they called it a death wobble.
> -tom
Not sure why they called it a death wobble
ahha! you will when it happens. you loose control. if you're really
moving, the vehicle feels like it leaves the ground!
|
| | |
Date: 23 Jun 2007 18:39:24
From:
Subject: Re: High Speed Shimmy
|
Gene Daniels writes:
>>>> Animation of shimmy
>>>> Animation of death wobble
>>> Ummm. Huh?
>> Links:
>> Animation of shimmy:
http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.avi
>> Animation of death wobble:
http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/weave_0_65.avi
>> Not sure why they called it a death wobble.
The shimmy animation (wobble) is incorrect for bicycles. The front
wheel runs with nearly imperceptible deviation from a straight line,
(not leaving a wavy line on dry pavement if the tire were wet).
However, the headtube moves from side to side, the top- and downtube
twisting against the mass of the rider on the saddle. Shimmy stops if
solid contact with the saddle ceases (slightly unloading the saddle).
Damping lateral motion of the head tube, by hands on the bars or leg
laid against the top tube, also stops shimmy.
It is causes in some instances by "the death grip" of a rider
anticipating shimmy because muscular response is about the same as
bicycle shimmy. Holding the bars loosely avoids that, especially if
the rider is tired and cold at the brink of shivering.
> Not sure why they called it a death wobble
> Aha! You will when it happens. You loose control. If you're
> really moving, the vehicle feels like it leaves the ground!
You say that as if you have crashed with this effect. Maybe you can
clarify the circumstances and what changed before the incident and
what has occurred since, to not have it recur.
Jobst Brandt
|
| | | |
Date: 25 Jun 2007 12:10:29
From: dvt
Subject: Re: High Speed Shimmy
|
jobst.brandt@stanfordalumni.org wrote:
>>> Animation of shimmy:
>>> <http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.avi>
> The shimmy animation (wobble) is incorrect for bicycles. The front
> wheel runs with nearly imperceptible deviation from a straight line,
> (not leaving a wavy line on dry pavement if the tire were wet).
I don't think that's true for all bikes.
My commuter bike, laden with fenders, a mudflap, and a headlight mounted
to the front fork, shimmies like crazy when ridden no-hands, even at
fairly slow speed (<20 mph). I can see the front wheel wobble back and
forth. Different mudflaps affect the shimmy. Going from drop bars to
flat bars made the shimmy worse.
Your bike's front wheel may stay pointed straight ahead during shimmy.
Mine doesn't.
--
Dave
dvt at psu dot edu
|
| | | | |
Date: 25 Jun 2007 21:59:41
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <f5opdl$1gcu$1@f04n12.cac.psu.edu >, dvt <dvt+usenet@psu.edu>
wrote:
> jobst.brandt@stanfordalumni.org wrote:
> >>> Animation of shimmy:
> >>> <http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.av
> >>> i>
>
> > The shimmy animation (wobble) is incorrect for bicycles. The front
> > wheel runs with nearly imperceptible deviation from a straight
> > line, (not leaving a wavy line on dry pavement if the tire were
> > wet).
>
> I don't think that's true for all bikes.
>
> My commuter bike, laden with fenders, a mudflap, and a headlight
> mounted to the front fork, shimmies like crazy when ridden no-hands,
> even at fairly slow speed (<20 mph). I can see the front wheel wobble
> back and forth. Different mudflaps affect the shimmy. Going from drop
> bars to flat bars made the shimmy worse.
>
> Your bike's front wheel may stay pointed straight ahead during
> shimmy. Mine doesn't.
Is the front wheel's track on the ground straight or serpentine when it
shimmies? When my bikes shimmy, I don't go weaving down the road- I
continue on in a straight line. Maybe your bike shimmies differently?
|
| | | | | |
Date: 26 Jun 2007 09:58:59
From: dvt
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <f5opdl$1gcu$1@f04n12.cac.psu.edu>, dvt <dvt+usenet@psu.edu>
> wrote:
>> Your bike's front wheel may stay pointed straight ahead during
>> shimmy. Mine doesn't.
> Is the front wheel's track on the ground straight or serpentine when it
> shimmies? When my bikes shimmy, I don't go weaving down the road- I
> continue on in a straight line. Maybe your bike shimmies differently?
I haven't ridden through a puddle and then allowed shimmy. I'll do that
sometime when it rains.
As you may have seen elsewhere in this thread, my handlebars wobble
quite noticeably. The wheel must be oscillating about the headset in
order to force that movement. I still go down the road in the same
general direction, albeit wobbly.
--
Dave
dvt at psu dot edu
Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)
|
| | | | | | |
Date: 26 Jun 2007 17:44:18
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <f5r633$1bim$1@f04n12.cac.psu.edu >, dvt <dvt+usenet@psu.edu>
wrote:
> Tim McNamara wrote:
> > In article <f5opdl$1gcu$1@f04n12.cac.psu.edu>, dvt
> > <dvt+usenet@psu.edu> wrote:
> >> Your bike's front wheel may stay pointed straight ahead during
> >> shimmy. Mine doesn't.
>
> > Is the front wheel's track on the ground straight or serpentine
> > when it shimmies? When my bikes shimmy, I don't go weaving down
> > the road- I continue on in a straight line. Maybe your bike
> > shimmies differently?
>
> I haven't ridden through a puddle and then allowed shimmy. I'll do
> that sometime when it rains.
>
> As you may have seen elsewhere in this thread, my handlebars wobble
> quite noticeably. The wheel must be oscillating about the headset in
> order to force that movement. I still go down the road in the same
> general direction, albeit wobbly.
Yes, there's going to be some rotation of the headset as the frame whips
back and forth. However, the magnitude of rotation might be actually
quite small even though it's visually dramatic- not enough to alter the
track of the tire on the ground. There may even be some visual
illusion, too.
|
| |
Date: 22 Jun 2007 15:42:08
From: andresmuro@aol.com
Subject: Re: High Speed Shimmy
|
On Jun 21, 10:27 pm, jim beam <spamvor...@bad.example.net > wrote:
> andresm...@aol.com wrote:
> > On Jun 20, 8:53 am, jobst.bra...@stanfordalumni.org wrote:
> >> someone writes:
> >>>>> I know this is a well worn topic, but, I've experienced shimmy
> >>>>> with my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have
> >>>>> been riding the same hills for 15 years with no problems (for the
> >>>>> past 8 years on Cannondale, which, sadly developed a cracked
> >>>>> frame). The shop tightened the spokes, which helped but did not
> >>>>> solve the problem. Anyway, the point of the post is to poll folks
> >>>>> - is this a Lightspeed issue?
> >>>> You didn't say whether the shimmy occurs riding no-hands or whether
> >>>> you experience it with hands on the bars.
> >>> Troll-o-meter says: 3.2
> >>> In what universe to you live in? One in which riding no-hands at
> >>> 35-40mph is common enough that you'd think it's valid that this
> >>> point should be clarified?
> >> I guess you don't ride bike or you would know that max speeds on fast
> >> descents are achieved with hands on the bar stem in a tight crouch.
> >> Even in that position the soft mass of the hands on the stem suppress
> >> shimmy for most bicycles.
>
> >> Just the same coasting at 40mph riding no-hands in common among the
> >> people with whom I ride. Typically coasting down CAL HWY84 to La
> >> Honda is a 40mph descent that rolls well sitting up with hands behind
> >> ones back.
>
> >> I've noticed that riders sneer incredibly when I ask whether their
> >> bicycle rides straight when ridden no-hands, because I note that the
> >> wheels are skewed to one another. The response often is "I don't ride
> >> no-hands!" in a tone as if I had asked whether they ride without a
> >> helmet.
>
> >> Where have all the young folks of bicycling gone?
>
> >>http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> >> Jobst Brandt
>
> > man, you ride a huge bike. Just curious, what size is it? what is your
> > inseam? where do you buy pants?
>
> > Andres
>
> if he bothered to extend his seat post, he could have a smaller,
> lighter, more stable frame. but that would be too analytical.
There may be some reasons why he chooses a bigger frame. First, his
seatpost shows a good chunk. Second, a smaller frame would require
that he rises his handlebars more. he might like a long top tube to
stretch out.
there is a picture in which he is sitting and with his stretched leg
he can touch the ground. Meaning that even with that big frame and a
good chunk of seatpost showing, his legs touch the ground ok. That
means that he has room between his crotch and toptube when he stradles
the frame
Possibly, with a smaller frame, he would need a longer seatpost and
stem and and he would need to rise his stem a bit. So, he might prefer
a shorter seatpost, the stem not showing too much and the bars leveled
with the saddle.
While a smaller frame may be lighter, it will not necessarily be more
stable considering what I mentioned above. Regarding stability, I
think that he is probably pretty stable considering that the pictures
show him riding off road with skinny tires, climbing endless mountains
and leaning on the now famous avocet tire publicity. Also, he calims
to be able to ride no hand comfortably at 40 plus mph. I have no
reason to disbelieve him so, his stability is probably just fine.
Of course, mine are speculations based on common sense about biking.
May be he can tell us why he prefers a frame on the larger end.
Regadless of the size of frame, he still has an unusually long
inseam.
Andres
|
| |
Date: 22 Jun 2007 18:21:00
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 21, 7:11 am, Johan Bornman <coldb...@telkomsa.net > wrote:
> On Jun 20, 4:53 pm, jobst.bra...@stanfordalumni.org wrote:
>
> > I've noticed that riders sneer incredibly when I ask whether their
> > bicycle rides straight when ridden no-hands, because I note that the
> > wheels are skewed to one another. The response often is "I don't ride
> > no-hands!" in a tone as if I had asked whether they ride without a
> > helmet.
>
> Jobst, I agree with this comment. People find it incredulous when I
> ask them if they can induce shimmy by riding no-hands, gently
> accelerating down a hill until they reach shimmy speed. The thought of
> induced shimmy doesn't seem as outrageous to them as the thought of
> riding no-hands.
>
> Riding no-hands gives you a nice relief for crouched riding, it allows
> you to sit up completely straigt, stretch a little, practice your
> balance a little and generally puts you in touch with your bike again.
> I especially like to prove (to myself) that riding no-hands over minor
> bumps does not induce self-steering.
>
> But then again, you lament the absense of youthfull biking - I see it
> in many other ways, the stunts kids do on their bikes nowadays really
> astonish me. Perhaps we've gone from riding no-hands to riding railway
> tracks, 2km wheelies, jumping onto tables and getting seriously
> airborne.
>
> Johan Bornman
stunts? glamorous and pays well, paves well into the future escape.
hollywood is more fun than 11/10ths tarzan
|
| |
Date: 22 Jun 2007 18:06:23
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 22, 12:24 pm, "David L. Johnson" <david.john...@lehigh.edu >
wrote:
> Michael Warner wrote:
> > On Fri, 22 Jun 2007 05:24:33 GMT, Mike Jacoubowsky wrote:
>
> >> Still think it was a problem with the bike? (And yes, we did try different
> >> wheels. She wouldn't consider changing her position on the bike, so we
> >> couldn't test for that.)
>
> > I'm curious - would you (or other bike shop owners here) ever give a refund
> > to someone with shimmy problems on one of your bikes, assuming the
> > bike wasn't faulty in any way?
>
> > I ask because a friend of mine tried two different (carbon) bikes from a
> > local shop after paying for the first, shimmied on both, asked for a refund
> > and was refused. He ended up taking the first bike and adapting to the
> > different geometry and feel, and AFAIK rarely has that problem now.
>
> It's a bit disappointing to still see so little understanding of shimmy.
> Shimmy is not caused by a single thing, but by the chance combination
> of the various pieces that go into the system, and this includes,
> significantly, the rider. No bike design (at least for a bike under 40
> pounds) could eliminate the possibility of shimmy for all riders under
> all circumstances. And, if you do experience shimmy, and make any
> change (position, tires, wheels, frame, etc.), you will change the
> system, and that may be enough to stop the shimmy.
>
> I regularly experienced shimmy with my first road bike. I have seen
> others have really bad shimmy; one quite recently. For all the
> scariness, it's curious that very few riders actually fall from a shimmy.
>
> What I finally learned, and what I tell people to do, is to simply get
> the weight off the saddle if you start to shimmy. Whatever combination
> of components managed to arrive at that resonance that produces the
> shimmy, the resulting motion is rotating about the seat tube (that's why
> the front of the bike wobbles back and forth, it is oscillating around
> the axis of the seat tube). Removing one's butt from the saddle removes
> the anchor for that rotation, and it stops. Of course, some guy with a
> death grip on the bars shimmying downhill at 40+mph is not going to
> listen to that, but it works. I also find that I descend better with my
> weight on the pedals rather than on the saddle.
>
> --
>
> David L. Johnson
>
> As far as the laws of mathematics refer to reality, they are not
> certain, and as far as they are certain, they do not refer to reality.
> -- Albert Einstein- Hide quoted text -
>
> - Show quoted text -
really? I lean forward to dirt bike weight the front wheel, as with
the add weight but sit on the seat experiment, butbutbut off course
when I lean forward weight comes of the saddle and effectively with
the add weight idea, as well. more Godel?
|
| |
Date: 22 Jun 2007 18:01:24
From: datakoll
Subject: Re: High Speed Shimmy
|
yep. the causeway is a drawwwwbridge, 3' lane, broekn cocktail grass,
imported green ale glass, assorted boat-trailer hardware AND THE
TRAFFIC IS STONED 2 DAYS 4 NIGHTS, 90 IQ models driving loaned pimp
mobiles...
http://maps.google.com/maps?um=1&tab=wl&ie=UTF-8&oe=UTF-8&rls=com.microsoft%3A*%3AIE-SearchBox&rlz=1I7GGLJ&q=punta%20rassa%2C%20fl
there occured the death wobble during RUSHYAAAHHAAAAAAA hour(s) at 30
mph with a triax right behind me followed bya ford station wagon. holy
excrement!
the mex triax destroeyed the bridge doing thankyoumam's on the brakes.
wobble can be fearsome.
the weights idea loads bearings and what have you, removing excess
clearanmces and out of syhchnnn ellipsoids that I assume occur on new
equipment as well as more frequently old junk.
|
| |
Date: 22 Jun 2007 10:16:51
From: Camilo
Subject: Re: High Speed Shimmy
|
On Jun 21, 3:11 am, Johan Bornman <coldb...@telkomsa.net > wrote:
> On Jun 20, 4:53 pm, jobst.bra...@stanfordalumni.org wrote:
>
> But then again, you lament the absense of youthfull biking - I see it
> in many other ways, the stunts kids do on their bikes nowadays really
> astonish me. Perhaps we've gone from riding no-hands to riding railway
> tracks, 2km wheelies, jumping onto tables and getting seriously
> airborne.
>
> Johan Bornman
Word.
Kids these days - at least as far as I can see locally - are riding
bikes a lot, both casually around the neighborhood, and on
whateveryacallem bikes hopping curbs and doing tricks. They're not on
racing bikes (although there seems to be a revival in that as well).
No helmets, or far fewer, which in spite of my personal helmet use,
make me feel that bicycling is getting back to what it was when I was
a kid, hopping on the bike and goofing off without looking at it as
some mysterious, dangerous sport.
|
| | |
Date: 22 Jun 2007 13:14:39
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <1182532611.679932.152740@g37g2000prf.googlegroups.com >,
Camilo <campascual@yahoo.com > wrote:
> On Jun 21, 3:11 am, Johan Bornman <coldb...@telkomsa.net> wrote:
> > On Jun 20, 4:53 pm, jobst.bra...@stanfordalumni.org wrote:
>
> >
> > But then again, you lament the absense of youthfull biking - I see
> > it in many other ways, the stunts kids do on their bikes nowadays
> > really astonish me. Perhaps we've gone from riding no-hands to
> > riding railway tracks, 2km wheelies, jumping onto tables and
> > getting seriously airborne.
> >
> > Johan Bornman
>
> Word.
>
> Kids these days - at least as far as I can see locally - are riding
> bikes a lot, both casually around the neighborhood, and on
> whateveryacallem bikes hopping curbs and doing tricks. They're not on
> racing bikes (although there seems to be a revival in that as well).
> No helmets, or far fewer, which in spite of my personal helmet use,
> make me feel that bicycling is getting back to what it was when I was
> a kid, hopping on the bike and goofing off without looking at it as
> some mysterious, dangerous sport.
It may vary by where you live. Around here I see some kids on various
types of bikes JRA and some kids on BMX bikes doing tricks and the like.
But I see more kids on skateboards doing tricks than bikes. And for
every kid I see riding a bike I see 20 adults riding bikes- the reverse
of the situation when I was a kid. On the upside, I see about 10 times
as many adult cyclists than I saw 15 years ago. I might see 50-100
cyclists some days.
|
| |
Date: 22 Jun 2007 07:54:06
From: Tom Nakashima
Subject: Re: High Speed Shimmy
|
Animation of shimmy
Animation of death wobble
-tom
|
| | |
Date: 22 Jun 2007 10:39:27
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <f5gnqe$j6k$1@news.Stanford.EDU >,
"Tom Nakashima" <tom@slac.stanford.edu > wrote:
> Animation of shimmy
>
> Animation of death wobble
Ummm. Huh?
|
| | | |
Date: 22 Jun 2007 09:02:50
From: Tom Nakashima
Subject: Re: High Speed Shimmy
|
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-13AF48.10392722062007@news.iphouse.com...
> In article <f5gnqe$j6k$1@news.Stanford.EDU>,
> "Tom Nakashima" <tom@slac.stanford.edu> wrote:
>
>> Animation of shimmy
>>
>> Animation of death wobble
>
> Ummm. Huh?
Links:
Animation of shimmy:
http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.avi
Animation of death wobble:
http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/weave_0_65.avi
Not sure why they called it a death wobble.
-tom
|
| | | | |
Date: 22 Jun 2007 14:11:58
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <f5grra$ml4$1@news.Stanford.EDU >,
"Tom Nakashima" <tom@slac.stanford.edu > wrote:
> "Tim McNamara" <timmcn@bitstream.net> wrote in message
> news:timmcn-13AF48.10392722062007@news.iphouse.com...
> > In article <f5gnqe$j6k$1@news.Stanford.EDU>,
> > "Tom Nakashima" <tom@slac.stanford.edu> wrote:
> >
> >> Animation of shimmy
> >>
> >> Animation of death wobble
> >
> > Ummm. Huh?
>
> Links:
> Animation of shimmy:
> http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.avi
>
> Animation of death wobble:
> http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/weave_0_65.avi
>
> Not sure why they called it a death wobble.
Ah. Thanks! I think it's called a "death wobble" because it feel like
you're going to crash and die.
|
| | | | | |
Date: 22 Jun 2007 12:45:16
From: Tom Nakashima
Subject: Re: High Speed Shimmy
|
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-165FD1.14115822062007@news.iphouse.com...
> In article <f5grra$ml4$1@news.Stanford.EDU>,
> "Tom Nakashima" <tom@slac.stanford.edu> wrote:
>
>> "Tim McNamara" <timmcn@bitstream.net> wrote in message
>> news:timmcn-13AF48.10392722062007@news.iphouse.com...
>> > In article <f5gnqe$j6k$1@news.Stanford.EDU>,
>> > "Tom Nakashima" <tom@slac.stanford.edu> wrote:
>> >
>> >> Animation of shimmy
>> >>
>> >> Animation of death wobble
>> >
>> > Ummm. Huh?
>>
>> Links:
>> Animation of shimmy:
>> http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/wobble_0_65.avi
>>
>> Animation of death wobble:
>> http://www2.ee.ic.ac.uk/cap/cappp/projects/2/files/weave_0_65.avi
>>
>> Not sure why they called it a death wobble.
>
> Ah. Thanks! I think it's called a "death wobble" because it feel like
> you're going to crash and die.
I'm not sure if a death wobble can occur on a bicycle, unless you
apply a hard front brake on loose gravel or slippery road without
touching the rear brakes.
I never felt the "death wobble" on a bicycle, but I did feel it on my
motorcycle in a panic braking situation while downshifting (using the
engine's compression) at the same time.
-tom
|
| | | |
Date: 22 Jun 2007 08:57:28
From: Tom Nakashima
Subject: Re: High Speed Shimmy
|
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-13AF48.10392722062007@news.iphouse.com...
> In article <f5gnqe$j6k$1@news.Stanford.EDU>,
> "Tom Nakashima" <tom@slac.stanford.edu> wrote:
>
>> Animation of shimmy
>>
>> Animation of death wobble
>
> Ummm. Huh?
They were suppose to be links, but it didn't go though.
I'll see if I could find the URL.
-tom
|
| |
Date: 22 Jun 2007 14:06:10
From: datakoll
Subject: Re: High Speed Shimmy
|
try adding a weight, start with say 5-8lbs, to the top tube. slide
weight forwadr. does shimmy stop?
experiment tends to indicate a general looseness in the mechanism from
contact surface to headset possibley as noted preceeding back to rear
hub looseness in complementary and additive hinge effects. that is,
the wheel may be balanced and true yet shimmy occurs.
|
| | |
Date: 23 Jun 2007 02:08:51
From:
Subject: Re: High Speed Shimmy
|
Gene Daniels writes:
> Try adding a weight, start with say 5-8lbs, to the top tube. slide
> weight forward. does shimmy stop?
> Experiment tends to indicate a general looseness in the mechanism
> from contact surface to headset possibly as noted preceding back to
> rear hub looseness in complementary and additive hinge effects. that
> is, the wheel may be balanced and true yet shimmy occurs.
That isn't what I discovered in pursuing causes of shimmy. I filled
the front tire (entirely) with water without any effect. I tried Rolf
Vector Pro and Bontrager paired spoked wheels that had no effect.
Damon Rinard repeated that experiment and found the same results, only
that he instrumented the bicycle with an accelerometer on the head
tube (the part of the bicycle that actually shimmies) and found the
paired spoke wheels and a 36 spoke standard wheel had the same shimmy
frequency, proving That shimmy is developed by the frame. These were
all no-hands tests on a smooth descent, the same as the one I did.
http://www.sheldonbrown.com/brandt/shimmy.html
Jobst Brandt
|
| | | |
Date: 22 Jun 2007 19:25:42
From: jim beam
Subject: Re: High Speed Shimmy
|
jobst.brandt@stanfordalumni.org wrote:
> Gene Daniels writes:
>
>> Try adding a weight, start with say 5-8lbs, to the top tube. slide
>> weight forward. does shimmy stop?
>
>> Experiment tends to indicate a general looseness in the mechanism
>> from contact surface to headset possibly as noted preceding back to
>> rear hub looseness in complementary and additive hinge effects. that
>> is, the wheel may be balanced and true yet shimmy occurs.
>
> That isn't what I discovered in pursuing causes of shimmy. I filled
> the front tire (entirely) with water without any effect.
what effect exactly did you /intent/ it should have? water doesn't
weigh that much. it's not affecting elasticity. and it doesn't affect
the frame.
> I tried Rolf
> Vector Pro and Bontrager paired spoked wheels that had no effect.
>
> Damon Rinard repeated that experiment and found the same results, only
> that he instrumented the bicycle with an accelerometer on the head
> tube (the part of the bicycle that actually shimmies) and found the
> paired spoke wheels and a 36 spoke standard wheel had the same shimmy
> frequency, proving That shimmy is developed by the frame.
the frame is primarily responsible, but the wheels affect it. both have
elasticity, and when given a mass load, will have a resonant frequency.
if the frequencies of frame and wheel coincide, you have a problem.
and paired spoke wheels, as you should know, have no effect on
elasticity. what /does/ make a difference is using spokes with greater
stiffness, i.e. unbutted 2.0mm spokes vs usual 1.8mm butted or less.
> These were
> all no-hands tests on a smooth descent, the same as the one I did.
>
> http://www.sheldonbrown.com/brandt/shimmy.html
>
there's lots in your faq's that needs revision. "It is driven by
gyroscopic forces of the front wheel" for example. lack of mention of
using large diameter frame tube to mitigate torsion is somewhat apparent
also.
if you want to claim credit for identifying a problem jobst, you need to
propose a solution. blaming the rider for bike shimmy is like blaming
the driver for suicide doors on old cars when they open unintentionally.
|
| | | | |
Date: 23 Jun 2007 19:04:05
From:
Subject: Re: High Speed Shimmy
|
http://www.jimbeam.com/beam/default.aspx? writes:
>>> Try adding a weight, start with say 5-8lbs, to the top tube. slide
>>> weight forward. does shimmy stop?
>>> Experiment tends to indicate a general looseness in the mechanism
>>> from contact surface to headset possibly as noted preceding back
>>> to rear hub looseness in complementary and additive hinge
>>> effects. that is, the wheel may be balanced and true yet shimmy
>>> occurs.
>> That isn't what I discovered in pursuing causes of shimmy. I
>> filled the front tire (entirely) with water without any effect.
> what effect exactly did you /intent/ it should have? water doesn't
> weigh that much. it's not affecting elasticity. and it doesn't
> affect the frame.
>> I tried Rolf Vector Pro and Bontrager paired spoked wheels that had
>> no effect.
>> Damon Rinard repeated that experiment and found the same results,
>> only that he instrumented the bicycle with an accelerometer on the
>> head tube (the part of the bicycle that actually shimmies) and
>> found the paired spoke wheels and a 36 spoke standard wheel had the
>> same shimmy frequency, proving That shimmy is developed by the
>> frame.
> the frame is primarily responsible, but the wheels affect it. both
> have elasticity, and when given a mass load, will have a resonant
> frequency. if the frequencies of frame and wheel coincide, you have
> a problem.
> and paired spoke wheels, as you should know, have no effect on
> elasticity. what /does/ make a difference is using spokes with
> greater stiffness, i.e. unbutted 2.0mm spokes vs usual 1.8mm butted
> or less.
These tests were done involving a patent infringement case involving
paired spoke wheels and low spoke count. Therefore, it was germane to
the case to show that neither number of spokes, weight of wheel, nor
36-spoke conventional spoking and low count paired spoking had any
perceptible effect on shimmy.
>> These were all no-hands tests on a smooth descent, the same as the
>> one I did.
http://www.sheldonbrown.com/brandt/shimmy.html
> there's lots in your faq's that needs revision. "It is driven by
> gyroscopic forces of the front wheel" for example. lack of mention
> of using large diameter frame tube to mitigate torsion is somewhat
> apparent also.
> if you want to claim credit for identifying a problem jobst, you
> need to propose a solution. blaming the rider for bike shimmy is
> like blaming the driver for suicide doors on old cars when they open
> unintentionally.
You might apply that axiom to your own writing rather than responding
rudely to what others write.
Jobst Brandt
|
| | | | | |
Date: 23 Jun 2007 13:18:55
From: jim beam
Subject: Re: High Speed Shimmy
|
jobst.brandt@stanfordalumni.org wrote:
> http://www.jimbeam.com/beam/default.aspx? writes:
>
>>>> Try adding a weight, start with say 5-8lbs, to the top tube. slide
>>>> weight forward. does shimmy stop?
>
>>>> Experiment tends to indicate a general looseness in the mechanism
>>>> from contact surface to headset possibly as noted preceding back
>>>> to rear hub looseness in complementary and additive hinge
>>>> effects. that is, the wheel may be balanced and true yet shimmy
>>>> occurs.
>
>>> That isn't what I discovered in pursuing causes of shimmy. I
>>> filled the front tire (entirely) with water without any effect.
>
>> what effect exactly did you /intent/ it should have? water doesn't
>> weigh that much. it's not affecting elasticity. and it doesn't
>> affect the frame.
>
>>> I tried Rolf Vector Pro and Bontrager paired spoked wheels that had
>>> no effect.
>
>>> Damon Rinard repeated that experiment and found the same results,
>>> only that he instrumented the bicycle with an accelerometer on the
>>> head tube (the part of the bicycle that actually shimmies) and
>>> found the paired spoke wheels and a 36 spoke standard wheel had the
>>> same shimmy frequency, proving That shimmy is developed by the
>>> frame.
>
>> the frame is primarily responsible, but the wheels affect it. both
>> have elasticity, and when given a mass load, will have a resonant
>> frequency. if the frequencies of frame and wheel coincide, you have
>> a problem.
>
>> and paired spoke wheels, as you should know, have no effect on
>> elasticity. what /does/ make a difference is using spokes with
>> greater stiffness, i.e. unbutted 2.0mm spokes vs usual 1.8mm butted
>> or less.
>
> These tests were done involving a patent infringement case involving
> paired spoke wheels and low spoke count. Therefore, it was germane to
> the case to show that neither number of spokes, weight of wheel, nor
> 36-spoke conventional spoking and low count paired spoking had any
> perceptible effect on shimmy.
ah, the jobstian "perceptible" get-out! hard to argue about what's
"perceptible" isn't it - since it's personal and all! eschew
measurement! i perceive i can ride at 100mph! up hill!
how you can write that stuff with a straight face is quite amazing.
damon rinard's tests show clearly the effect of spoke gauge on stiffness
[what i was talking about, not your red herring]. did you present that
in your lawsuit? i'm guessing not.
>
>>> These were all no-hands tests on a smooth descent, the same as the
>>> one I did.
>
> http://www.sheldonbrown.com/brandt/shimmy.html
>
>> there's lots in your faq's that needs revision. "It is driven by
>> gyroscopic forces of the front wheel" for example. lack of mention
>> of using large diameter frame tube to mitigate torsion is somewhat
>> apparent also.
>
>> if you want to claim credit for identifying a problem jobst, you
>> need to propose a solution. blaming the rider for bike shimmy is
>> like blaming the driver for suicide doors on old cars when they open
>> unintentionally.
>
> You might apply that axiom to your own writing rather than responding
> rudely to what others write.
jobst, update your "faq"! the cure for shimmy is stiffer [big tube]
frames [and stiffer wheels help to a smaller degree]. frames don't
shimmy "driven by gyroscopic forces". rather than bleat about the
problem and blame riders, post the solution and improve the situation!!
[was that being rude?]
|
| | | | | | |
Date: 23 Jun 2007 18:50:34
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> the cure for shimmy is stiffer [big tube] frames [and stiffer wheels
> help to a smaller degree].
You are flip-flopping, jim, since you claimed earlier than changing to
2.0 mm drive side spokes in the rear wheel stops shimmy. That's not a
"small degree."
> frames don't shimmy "driven by gyroscopic forces".
Then what is the driver of shimmy in your opinion?
|
| | | | | | | |
Date: 23 Jun 2007 17:33:41
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> the cure for shimmy is stiffer [big tube] frames [and stiffer wheels
>> help to a smaller degree].
>
> You are flip-flopping, jim, since you claimed earlier than changing to
> 2.0 mm drive side spokes in the rear wheel stops shimmy. That's not a
> "small degree."
read my posts again retard - you're misunderstanding [and misquoting]
me. [but that's not breaking news however.]
>
>> frames don't shimmy "driven by gyroscopic forces".
>
> Then what is the driver of shimmy in your opinion?
the self-correction associated with caster. that's why ski-bikes [that
mean no wheels timmy - so no gyro forces] still shimmy. you're
evidently too retarded to ever read - this has been discussed at length.
fogel was the driver of the last go around as i recall.
|
| | | | | | | | |
Date: 24 Jun 2007 00:01:27
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> the cure for shimmy is stiffer [big tube] frames [and stiffer
> >> wheels help to a smaller degree].
> >
> > You are flip-flopping, jim, since you claimed earlier than changing
> > to 2.0 mm drive side spokes in the rear wheel stops shimmy. That's
> > not a "small degree."
>
> read my posts again retard - you're misunderstanding [and misquoting]
> me. [but that's not breaking news however.]
You should take your own advice and read back through your posts about
shimmy over the past few years. Google is your friend... well, not
actually *your* friend but you know what I mean. You'd notice that
people who know this stuff far better than you keep correcting your
errors about shimmy (among other topics) and you keep rejecting the
correction, apparently so convinced of your rightness that you can't
even conceive that you might be wrong- attributing the disagreement from
others to conspiracy theories with Jobst as the Moriarty to your Holmes.
Rereading those old threads really underscores your utter lack of
credibility, jim.
> >> frames don't shimmy "driven by gyroscopic forces".
> >
> > Then what is the driver of shimmy in your opinion?
>
> the self-correction associated with caster. that's why ski-bikes
> [that mean no wheels timmy - so no gyro forces] still shimmy. you're
> evidently too retarded to ever read - this has been discussed at
> length.
You've not answered the question; well, to be fair, you've answered the
question only partially. Keep going, you might get there eventually.
What initiates and maintains the self-correction? Why is there a
critical threshold speed at which shimmy appears? Why does the bike
typically have to be loaded in a specific way? Under what set of
circumstances does shimmy occur? And how does the existence of shimmy
tally with your claim that bicycles are inherently stable?
Time to cut the crap and the games, jim. Show us what you're made of.
Prove you know what you're talking about.
|
| | | | | | | | | |
Date: 23 Jun 2007 22:43:12
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> the cure for shimmy is stiffer [big tube] frames [and stiffer
>>>> wheels help to a smaller degree].
>>> You are flip-flopping, jim, since you claimed earlier than changing
>>> to 2.0 mm drive side spokes in the rear wheel stops shimmy. That's
>>> not a "small degree."
>> read my posts again retard - you're misunderstanding [and misquoting]
>> me. [but that's not breaking news however.]
>
> You should take your own advice and read back through your posts about
> shimmy over the past few years. Google is your friend... well, not
> actually *your* friend but you know what I mean. You'd notice that
> people who know this stuff far better than you keep correcting your
> errors about shimmy (among other topics) and you keep rejecting the
> correction, apparently so convinced of your rightness that you can't
> even conceive that you might be wrong- attributing the disagreement from
> others to conspiracy theories with Jobst as the Moriarty to your Holmes.
> Rereading those old threads really underscores your utter lack of
> credibility, jim.
seems you can't read, retard. but that's not news.
>
>>>> frames don't shimmy "driven by gyroscopic forces".
>>> Then what is the driver of shimmy in your opinion?
>> the self-correction associated with caster. that's why ski-bikes
>> [that mean no wheels timmy - so no gyro forces] still shimmy. you're
>> evidently too retarded to ever read - this has been discussed at
>> length.
>
> You've not answered the question; well, to be fair, you've answered the
> question only partially. Keep going, you might get there eventually.
> What initiates and maintains the self-correction? Why is there a
> critical threshold speed at which shimmy appears? Why does the bike
> typically have to be loaded in a specific way? Under what set of
> circumstances does shimmy occur? And how does the existence of shimmy
> tally with your claim that bicycles are inherently stable?
>
> Time to cut the crap and the games, jim. Show us what you're made of.
> Prove you know what you're talking about.
fuck you retard. i've put out for your dumb ass countless fucking
times. and all i get is your dumb ass calling me a liar BECAUSE YOU'RE
TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you think i'm going
to re-write all that same old stuff just to hear that same old shit from
the retard? cram it up your retarded dumb ass.
|
| | | | | | | | | | |
Date: 24 Jun 2007 09:08:14
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <ZbSdnSUCp5PsmePbnZ2dnUVZ_hqdnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> the cure for shimmy is stiffer [big tube] frames [and stiffer
> >>>> wheels help to a smaller degree].
> >>> You are flip-flopping, jim, since you claimed earlier than
> >>> changing to 2.0 mm drive side spokes in the rear wheel stops
> >>> shimmy. That's not a "small degree."
> >> read my posts again retard - you're misunderstanding [and
> >> misquoting] me. [but that's not breaking news however.]
> >
> > You should take your own advice and read back through your posts
> > about shimmy over the past few years. Google is your friend...
> > well, not actually *your* friend but you know what I mean. You'd
> > notice that people who know this stuff far better than you keep
> > correcting your errors about shimmy (among other topics) and you
> > keep rejecting the correction, apparently so convinced of your
> > rightness that you can't even conceive that you might be wrong-
> > attributing the disagreement from others to conspiracy theories
> > with Jobst as the Moriarty to your Holmes. Rereading those old
> > threads really underscores your utter lack of credibility, jim.
>
> seems you can't read, retard. but that's not news.
>
> >
> >>>> frames don't shimmy "driven by gyroscopic forces".
> >>> Then what is the driver of shimmy in your opinion?
> >> the self-correction associated with caster. that's why ski-bikes
> >> [that mean no wheels timmy - so no gyro forces] still shimmy.
> >> you're evidently too retarded to ever read - this has been
> >> discussed at length.
> >
> > You've not answered the question; well, to be fair, you've answered
> > the question only partially. Keep going, you might get there
> > eventually. What initiates and maintains the self-correction? Why
> > is there a critical threshold speed at which shimmy appears? Why
> > does the bike typically have to be loaded in a specific way? Under
> > what set of circumstances does shimmy occur? And how does the
> > existence of shimmy tally with your claim that bicycles are
> > inherently stable?
> >
> > Time to cut the crap and the games, jim. Show us what you're made
> > of. Prove you know what you're talking about.
>
> fuck you retard. i've put out for your dumb ass countless fucking
> times. and all i get is your dumb ass calling me a liar BECAUSE
> YOU'RE TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you think
> i'm going to re-write all that same old stuff just to hear that same
> old shit from the retard? cram it up your retarded dumb ass.
So, in other words, you can't. I thought as much.
|
| | | | | | | | | | | |
Date: 24 Jun 2007 10:00:23
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <ZbSdnSUCp5PsmePbnZ2dnUVZ_hqdnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> the cure for shimmy is stiffer [big tube] frames [and stiffer
>>>>>> wheels help to a smaller degree].
>>>>> You are flip-flopping, jim, since you claimed earlier than
>>>>> changing to 2.0 mm drive side spokes in the rear wheel stops
>>>>> shimmy. That's not a "small degree."
>>>> read my posts again retard - you're misunderstanding [and
>>>> misquoting] me. [but that's not breaking news however.]
>>> You should take your own advice and read back through your posts
>>> about shimmy over the past few years. Google is your friend...
>>> well, not actually *your* friend but you know what I mean. You'd
>>> notice that people who know this stuff far better than you keep
>>> correcting your errors about shimmy (among other topics) and you
>>> keep rejecting the correction, apparently so convinced of your
>>> rightness that you can't even conceive that you might be wrong-
>>> attributing the disagreement from others to conspiracy theories
>>> with Jobst as the Moriarty to your Holmes. Rereading those old
>>> threads really underscores your utter lack of credibility, jim.
>> seems you can't read, retard. but that's not news.
>>
>>>>>> frames don't shimmy "driven by gyroscopic forces".
>>>>> Then what is the driver of shimmy in your opinion?
>>>> the self-correction associated with caster. that's why ski-bikes
>>>> [that mean no wheels timmy - so no gyro forces] still shimmy.
>>>> you're evidently too retarded to ever read - this has been
>>>> discussed at length.
>>> You've not answered the question; well, to be fair, you've answered
>>> the question only partially. Keep going, you might get there
>>> eventually. What initiates and maintains the self-correction? Why
>>> is there a critical threshold speed at which shimmy appears? Why
>>> does the bike typically have to be loaded in a specific way? Under
>>> what set of circumstances does shimmy occur? And how does the
>>> existence of shimmy tally with your claim that bicycles are
>>> inherently stable?
>>>
>>> Time to cut the crap and the games, jim. Show us what you're made
>>> of. Prove you know what you're talking about.
>> fuck you retard. i've put out for your dumb ass countless fucking
>> times. and all i get is your dumb ass calling me a liar BECAUSE
>> YOU'RE TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you think
>> i'm going to re-write all that same old stuff just to hear that same
>> old shit from the retard? cram it up your retarded dumb ass.
>
> So, in other words, you can't. I thought as much.
timmy gets upset because i won't play. poor timmy retard.
then again, maybe i should taunt you with the "gaussian" model...
|
| | | | | | | | | | | | |
Date: 24 Jun 2007 15:05:03
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <DrGdnRrHOue1PuPbnZ2dnUVZ_vzinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <ZbSdnSUCp5PsmePbnZ2dnUVZ_hqdnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> the cure for shimmy is stiffer [big tube] frames [and stiffer
> >>>>>> wheels help to a smaller degree].
> >>>>> You are flip-flopping, jim, since you claimed earlier than
> >>>>> changing to 2.0 mm drive side spokes in the rear wheel stops
> >>>>> shimmy. That's not a "small degree."
> >>>> read my posts again retard - you're misunderstanding [and
> >>>> misquoting] me. [but that's not breaking news however.]
> >>> You should take your own advice and read back through your posts
> >>> about shimmy over the past few years. Google is your friend...
> >>> well, not actually *your* friend but you know what I mean. You'd
> >>> notice that people who know this stuff far better than you keep
> >>> correcting your errors about shimmy (among other topics) and you
> >>> keep rejecting the correction, apparently so convinced of your
> >>> rightness that you can't even conceive that you might be wrong-
> >>> attributing the disagreement from others to conspiracy theories
> >>> with Jobst as the Moriarty to your Holmes. Rereading those old
> >>> threads really underscores your utter lack of credibility, jim.
> >> seems you can't read, retard. but that's not news.
> >>
> >>>>>> frames don't shimmy "driven by gyroscopic forces".
> >>>>> Then what is the driver of shimmy in your opinion?
> >>>> the self-correction associated with caster. that's why
> >>>> ski-bikes [that mean no wheels timmy - so no gyro forces] still
> >>>> shimmy. you're evidently too retarded to ever read - this has
> >>>> been discussed at length.
> >>> You've not answered the question; well, to be fair, you've
> >>> answered the question only partially. Keep going, you might get
> >>> there eventually. What initiates and maintains the
> >>> self-correction? Why is there a critical threshold speed at
> >>> which shimmy appears? Why does the bike typically have to be
> >>> loaded in a specific way? Under what set of circumstances does
> >>> shimmy occur? And how does the existence of shimmy tally with
> >>> your claim that bicycles are inherently stable?
> >>>
> >>> Time to cut the crap and the games, jim. Show us what you're
> >>> made of. Prove you know what you're talking about.
> >> fuck you retard. i've put out for your dumb ass countless fucking
> >> times. and all i get is your dumb ass calling me a liar BECAUSE
> >> YOU'RE TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you
> >> think i'm going to re-write all that same old stuff just to hear
> >> that same old shit from the retard? cram it up your retarded dumb
> >> ass.
> >
> > So, in other words, you can't. I thought as much.
>
> timmy gets upset because i won't play. poor timmy retard.
No, jim, I'm not even remotely upset. You're the one shouting.
> then again, maybe i should taunt you with the "gaussian" model...
When were you taunting me? I'm sorry if I missed it.
|
| | | | | | | | | | | | | |
Date: 24 Jun 2007 13:23:01
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <DrGdnRrHOue1PuPbnZ2dnUVZ_vzinZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <ZbSdnSUCp5PsmePbnZ2dnUVZ_hqdnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> Tim McNamara wrote:
>>>>>>> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>
>>>>>>>> the cure for shimmy is stiffer [big tube] frames [and stiffer
>>>>>>>> wheels help to a smaller degree].
>>>>>>> You are flip-flopping, jim, since you claimed earlier than
>>>>>>> changing to 2.0 mm drive side spokes in the rear wheel stops
>>>>>>> shimmy. That's not a "small degree."
>>>>>> read my posts again retard - you're misunderstanding [and
>>>>>> misquoting] me. [but that's not breaking news however.]
>>>>> You should take your own advice and read back through your posts
>>>>> about shimmy over the past few years. Google is your friend...
>>>>> well, not actually *your* friend but you know what I mean. You'd
>>>>> notice that people who know this stuff far better than you keep
>>>>> correcting your errors about shimmy (among other topics) and you
>>>>> keep rejecting the correction, apparently so convinced of your
>>>>> rightness that you can't even conceive that you might be wrong-
>>>>> attributing the disagreement from others to conspiracy theories
>>>>> with Jobst as the Moriarty to your Holmes. Rereading those old
>>>>> threads really underscores your utter lack of credibility, jim.
>>>> seems you can't read, retard. but that's not news.
>>>>
>>>>>>>> frames don't shimmy "driven by gyroscopic forces".
>>>>>>> Then what is the driver of shimmy in your opinion?
>>>>>> the self-correction associated with caster. that's why
>>>>>> ski-bikes [that mean no wheels timmy - so no gyro forces] still
>>>>>> shimmy. you're evidently too retarded to ever read - this has
>>>>>> been discussed at length.
>>>>> You've not answered the question; well, to be fair, you've
>>>>> answered the question only partially. Keep going, you might get
>>>>> there eventually. What initiates and maintains the
>>>>> self-correction? Why is there a critical threshold speed at
>>>>> which shimmy appears? Why does the bike typically have to be
>>>>> loaded in a specific way? Under what set of circumstances does
>>>>> shimmy occur? And how does the existence of shimmy tally with
>>>>> your claim that bicycles are inherently stable?
>>>>>
>>>>> Time to cut the crap and the games, jim. Show us what you're
>>>>> made of. Prove you know what you're talking about.
>>>> fuck you retard. i've put out for your dumb ass countless fucking
>>>> times. and all i get is your dumb ass calling me a liar BECAUSE
>>>> YOU'RE TOO FUCKING RETARDED TO FOLLOW BASIC MATH CONCEPTS. you
>>>> think i'm going to re-write all that same old stuff just to hear
>>>> that same old shit from the retard? cram it up your retarded dumb
>>>> ass.
>>> So, in other words, you can't. I thought as much.
>> timmy gets upset because i won't play. poor timmy retard.
>
> No, jim, I'm not even remotely upset. You're the one shouting.
no timmy, RETARD is shouting. "retard" is simple observation.
>
>> then again, maybe i should taunt you with the "gaussian" model...
>
> When were you taunting me? I'm sorry if I missed it.
so why do you bounce so obligingly, retard? anyone would think you're
too fucking dumb to figure it out the way you keep inviting more.
fucking retard.
|
| | | | | | | | | | | | | | |
Date: 24 Jun 2007 20:09:17
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <i_Kdne2LO9Y7T-PbnZ2dnUVZ_v3inZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <DrGdnRrHOue1PuPbnZ2dnUVZ_vzinZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <ZbSdnSUCp5PsmePbnZ2dnUVZ_hqdnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <v6-dnVt3OMZ7JuDbnZ2dnUVZ_ruknZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> Tim McNamara wrote:
> >>>>>>> In article <aeqdnb3Oxq6tHeDbnZ2dnUVZ_rfinZ2d@speakeasy.net>,
> >>>>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>>>
> >>>>>>>> the cure for shimmy is stiffer [big tube] frames [and
> >>>>>>>> stiffer wheels help to a smaller degree].
> >>>>>>> You are flip-flopping, jim, since you claimed earlier than
> >>>>>>> changing to 2.0 mm drive side spokes in the rear wheel stops
> >>>>>>> shimmy. That's not a "small degree."
> >>>>>> read my posts again retard - you're misunderstanding [and
> >>>>>> misquoting] me. [but that's not breaking news however.]
> >>>>> You should take your own advice and read back through your
> >>>>> posts about shimmy over the past few years. Google is your
> >>>>> friend... well, not actually *your* friend but you know what I
> >>>>> mean. You'd notice that people who know this stuff far better
> >>>>> than you keep correcting your errors about shimmy (among other
> >>>>> topics) and you keep rejecting the correction, apparently so
> >>>>> convinced of your rightness that you can't even conceive that
> >>>>> you might be wrong- attributing the disagreement from others to
> >>>>> conspiracy theories with Jobst as the Moriarty to your Holmes.
> >>>>> Rereading those old threads really underscores your utter lack
> >>>>> of credibility, jim.
> >>>> seems you can't read, retard. but that's not news.
> >>>>
> >>>>>>>> frames don't shimmy "driven by gyroscopic forces".
> >>>>>>> Then what is the driver of shimmy in your opinion?
> >>>>>> the self-correction associated with caster. that's why
> >>>>>> ski-bikes [that mean no wheels timmy - so no gyro forces]
> >>>>>> still shimmy. you're evidently too retarded to ever read -
> >>>>>> this has been discussed at length.
> >>>>> You've not answered the question; well, to be fair, you've
> >>>>> answered the question only partially. Keep going, you might
> >>>>> get there eventually. What initiates and maintains the
> >>>>> self-correction? Why is there a critical threshold speed at
> >>>>> which shimmy appears? Why does the bike typically have to be
> >>>>> loaded in a specific way? Under what set of circumstances does
> >>>>> shimmy occur? And how does the existence of shimmy tally with
> >>>>> your claim that bicycles are inherently stable?
> >>>>>
> >>>>> Time to cut the crap and the games, jim. Show us what you're
> >>>>> made of. Prove you know what you're talking about.
> >>>> fuck you retard. i've put out for your dumb ass countless
> >>>> fucking times. and all i get is your dumb ass calling me a liar
> >>>> BECAUSE YOU'RE TOO FUCKING RETARDED TO FOLLOW BASIC MATH
> >>>> CONCEPTS. you think i'm going to re-write all that same old
> >>>> stuff just to hear that same old shit from the retard? cram it
> >>>> up your retarded dumb ass.
> >>> So, in other words, you can't. I thought as much.
> >> timmy gets upset because i won't play. poor timmy retard.
> >
> > No, jim, I'm not even remotely upset. You're the one shouting.
>
> no timmy, RETARD is shouting. "retard" is simple observation.
Umm. jim? Look up a couple of layers in the citations. You were the
one shouting.
> >> then again, maybe i should taunt you with the "gaussian" model...
> >
> > When were you taunting me? I'm sorry if I missed it.
>
> so why do you bounce so obligingly, retard? anyone would think
> you're too fucking dumb to figure it out the way you keep inviting
> more. fucking retard.
It's no skin off my nose, jim. Apparently you are under the delusion
that you being a jerk and calling me names somehow does you credit and
me harm.
|
| | | | | | | | | | | | | | |
Date: 24 Jun 2007 21:14:44
From: Mike Jacoubowsky
Subject: High Speed Shimmy discussion leads to brain death?
|
> so why do you bounce so obligingly, retard? anyone would think you're too
> f###### dumb to figure it out the way you keep inviting more. f######
> retard.
OK, I've learned something here. There are more ways than just the use of
false handles to severely discredit your own ideas.
Seriously, this has taken a subject that merited serious discussion and
search for answers (and not just answers, but the reasons those answers
might be correct), and tossed it into the gutter. It's interesting to read a
rational discourse between people who believe very differently. You learn
quite a bit more than you would by simply taking something as a given. But
geez...
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| |
Date: 21 Jun 2007 13:12:59
From: andresmuro@aol.com
Subject: Re: High Speed Shimmy
|
On Jun 20, 8:53 am, jobst.bra...@stanfordalumni.org wrote:
> someone writes:
> >>> I know this is a well worn topic, but, I've experienced shimmy
> >>> with my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have
> >>> been riding the same hills for 15 years with no problems (for the
> >>> past 8 years on Cannondale, which, sadly developed a cracked
> >>> frame). The shop tightened the spokes, which helped but did not
> >>> solve the problem. Anyway, the point of the post is to poll folks
> >>> - is this a Lightspeed issue?
> >> You didn't say whether the shimmy occurs riding no-hands or whether
> >> you experience it with hands on the bars.
> > Troll-o-meter says: 3.2
> > In what universe to you live in? One in which riding no-hands at
> > 35-40mph is common enough that you'd think it's valid that this
> > point should be clarified?
>
> I guess you don't ride bike or you would know that max speeds on fast
> descents are achieved with hands on the bar stem in a tight crouch.
> Even in that position the soft mass of the hands on the stem suppress
> shimmy for most bicycles.
>
> Just the same coasting at 40mph riding no-hands in common among the
> people with whom I ride. Typically coasting down CAL HWY84 to La
> Honda is a 40mph descent that rolls well sitting up with hands behind
> ones back.
>
> I've noticed that riders sneer incredibly when I ask whether their
> bicycle rides straight when ridden no-hands, because I note that the
> wheels are skewed to one another. The response often is "I don't ride
> no-hands!" in a tone as if I had asked whether they ride without a
> helmet.
>
> Where have all the young folks of bicycling gone?
>
> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> Jobst Brandt
man, you ride a huge bike. Just curious, what size is it? what is your
inseam? where do you buy pants?
Andres
|
| | |
Date: 21 Jun 2007 21:27:12
From: jim beam
Subject: Re: High Speed Shimmy
|
andresmuro@aol.com wrote:
> On Jun 20, 8:53 am, jobst.bra...@stanfordalumni.org wrote:
>> someone writes:
>>>>> I know this is a well worn topic, but, I've experienced shimmy
>>>>> with my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have
>>>>> been riding the same hills for 15 years with no problems (for the
>>>>> past 8 years on Cannondale, which, sadly developed a cracked
>>>>> frame). The shop tightened the spokes, which helped but did not
>>>>> solve the problem. Anyway, the point of the post is to poll folks
>>>>> - is this a Lightspeed issue?
>>>> You didn't say whether the shimmy occurs riding no-hands or whether
>>>> you experience it with hands on the bars.
>>> Troll-o-meter says: 3.2
>>> In what universe to you live in? One in which riding no-hands at
>>> 35-40mph is common enough that you'd think it's valid that this
>>> point should be clarified?
>> I guess you don't ride bike or you would know that max speeds on fast
>> descents are achieved with hands on the bar stem in a tight crouch.
>> Even in that position the soft mass of the hands on the stem suppress
>> shimmy for most bicycles.
>>
>> Just the same coasting at 40mph riding no-hands in common among the
>> people with whom I ride. Typically coasting down CAL HWY84 to La
>> Honda is a 40mph descent that rolls well sitting up with hands behind
>> ones back.
>>
>> I've noticed that riders sneer incredibly when I ask whether their
>> bicycle rides straight when ridden no-hands, because I note that the
>> wheels are skewed to one another. The response often is "I don't ride
>> no-hands!" in a tone as if I had asked whether they ride without a
>> helmet.
>>
>> Where have all the young folks of bicycling gone?
>>
>> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>>
>> Jobst Brandt
>
> man, you ride a huge bike. Just curious, what size is it? what is your
> inseam? where do you buy pants?
>
> Andres
>
if he bothered to extend his seat post, he could have a smaller,
lighter, more stable frame. but that would be too analytical.
|
| |
Date: 21 Jun 2007 11:57:28
From: Jay Beattie
Subject: Re: High Speed Shimmy
|
On Jun 20, 6:32 pm, Johnny Sunset <sunsetss0...@yahoo.com > wrote:
> On Jun 20, 9:53 am, Jobst Brandt wrote:
>
> > ...
> > Where have all the young folks of bicycling gone?
>
> >http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> How can you stand to ride in such ugly terrain?
Ya know, I loved riding in California -- going out to the beach, along
the coast and up all the Jobst climbs (even with some of the same
people back in the '80s). In fact, I would not want to have been on
the pictured climb-a-thon on the coast with all the SJBC/LG guys
(Zanotti, Vierra, McBride) because they always stomped me in winter
series club races (the only time I got to race with that group). That
is like the top of the 1s pack in 1982. Half that group (and the
group on the porch) won the Cat's Hill at some point or another. I
don't think anyone went pro, though. I think Dave went to Europe for
a while but didn't do anything.
With that said, I still prefer the Columbia River Gorge better --
close to home, spectacular and lots of waterfalls. http://www.dlmark.net//gorgecrh.htm
-- Jay Beattie.
|
| |
Date: 21 Jun 2007 11:19:06
From: Jay Beattie
Subject: Re: High Speed Shimmy
|
On Jun 20, 6:32 pm, Johnny Sunset <sunsetss0...@yahoo.com > wrote:
> On Jun 20, 9:53 am, Jobst Brandt wrote:
>
> > ...
> > Where have all the young folks of bicycling gone?
>
> >http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> How can you stand to ride in such ugly terrain?
>
> --
> Tom Sherman - Holstein-Friesland Bovinia
> The weather is here, wish you were beautiful
|
| |
Date: 21 Jun 2007 04:11:02
From: Johan Bornman
Subject: Re: High Speed Shimmy
|
On Jun 20, 4:53 pm, jobst.bra...@stanfordalumni.org wrote:
>
> I've noticed that riders sneer incredibly when I ask whether their
> bicycle rides straight when ridden no-hands, because I note that the
> wheels are skewed to one another. The response often is "I don't ride
> no-hands!" in a tone as if I had asked whether they ride without a
> helmet.
>
Jobst, I agree with this comment. People find it incredulous when I
ask them if they can induce shimmy by riding no-hands, gently
accelerating down a hill until they reach shimmy speed. The thought of
induced shimmy doesn't seem as outrageous to them as the thought of
riding no-hands.
Riding no-hands gives you a nice relief for crouched riding, it allows
you to sit up completely straigt, stretch a little, practice your
balance a little and generally puts you in touch with your bike again.
I especially like to prove (to myself) that riding no-hands over minor
bumps does not induce self-steering.
But then again, you lament the absense of youthfull biking - I see it
in many other ways, the stunts kids do on their bikes nowadays really
astonish me. Perhaps we've gone from riding no-hands to riding railway
tracks, 2km wheelies, jumping onto tables and getting seriously
airborne.
Johan Bornman
|
| |
Date: 20 Jun 2007 20:41:55
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 20, 10:21 pm, Jobst Brandt wrote:
> Tom Sherman writes:
> >> ...
> >> Where have all the young folks of bicycling gone?
>
> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> > How can you stand to ride in such ugly terrain?
>
> Hold a stiff upper lip and suffer! Even while riding no-hands.
Can't compete with this for scenery: <http://tinyurl.com/2dmnjr > and
<http://tinyurl.com/2gprme >!!!
|
| |
Date: 20 Jun 2007 18:32:32
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 20, 9:53 am, Jobst Brandt wrote:
> ...
> Where have all the young folks of bicycling gone?
>
> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
How can you stand to ride in such ugly terrain?
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | |
Date: 21 Jun 2007 03:21:49
From:
Subject: Re: High Speed Shimmy
|
Tom Sherman writes:
>> ...
>> Where have all the young folks of bicycling gone?
http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
> How can you stand to ride in such ugly terrain?
Hold a stiff upper lip and suffer! Even while riding no-hands.
Jobst Brandt
|
| | |
Date: 20 Jun 2007 19:59:56
From: Bill
Subject: Re: High Speed Shimmy
|
Johnny Sunset wrote:
> On Jun 20, 9:53 am, Jobst Brandt wrote:
>> ...
>> Where have all the young folks of bicycling gone?
>>
>> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> How can you stand to ride in such ugly terrain?
Ugly? It's beautiful compared to where I now ride. I've been to a lot of
those places and miss them. The Big Basin--Mount Umunhum, and Highway 1
rides were some of the best. Once on Highway 1 I was looking down at the
ocean and saw a small Piper flying below me, about 50 feet over the
waves. A Kodak moment and no camera. I miss all the tall trees and being
able to be freezing when it was in the 80's in San Jose. Inland, where I
ride it is just hot and hotter. I never found that cave though.
Dang.
Bill Baka
>
> --
> Tom Sherman - Holstein-Friesland Bovinia
> The weather is here, wish you were beautiful
>
|
| |
Date: 20 Jun 2007 18:18:59
From: Zog The Undeniable
Subject: Re: High Speed Shimmy
|
mgrath@optonline.net wrote:
> I know this is a well worn topic, but, I've experienced shimmy with my
> new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
> same hills for 15 years with no problems (for the past 8 years on
> Cannondale, which, sadly developed a cracked frame). The shop
> tightened the spokes, which helped but did not solve the problem.
> Anyway, the point of the post is to poll folks - is this a Lightspeed
> issue?
> Thanks
> Matt
>
It's a complicated interaction between the bike geometry, stiffness,
natural resonant frequency and your own body and riding position. It
occasionally happens with certain riders and certain bikes. I
experienced shimmy/speed wobble when I was a teenager, but never on any
bike since (and except the fixie, they've all been up to 55mph or more).
Things to try would be checking your position, different tires and
moving any luggage (bar bags have a bad reputation for contributing to
shimmy). Last resort - try a different fork. You may be able to borrow
one from someone, all A-head forks being pretty swappable.
|
| |
Date: 20 Jun 2007 05:16:36
From: Qui si parla Campagnolo
Subject: Re: High Speed Shimmy
|
On Jun 19, 7:18 pm, mgr...@optonline.net wrote:
> I know this is a well worn topic, but, I've experienced shimmy with my
> new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
> same hills for 15 years with no problems (for the past 8 years on
> Cannondale, which, sadly developed a cracked frame). The shop
> tightened the spokes, which helped but did not solve the problem.
> Anyway, the point of the post is to poll folks - is this a Lightspeed
> issue?
> Thanks
> Matt
Speaking of Litespeed...had a persistent rumor that American Cycle
Group has gone belly up-anybody else heard this??
|
| |
Date: 20 Jun 2007 05:15:33
From: Qui si parla Campagnolo
Subject: Re: High Speed Shimmy
|
On Jun 19, 7:18 pm, mgr...@optonline.net wrote:
> I know this is a well worn topic, but, I've experienced shimmy with my
> new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
> same hills for 15 years with no problems (for the past 8 years on
> Cannondale, which, sadly developed a cracked frame). The shop
> tightened the spokes, which helped but did not solve the problem.
> Anyway, the point of the post is to poll folks - is this a Lightspeed
> issue?
> Thanks
> Matt
What wheels??
Could be lots of things and after correcting these it may still
shake.
HS, bike fit, fork/frame alignment, wheel dish, cable housing
length.....
|
| |
Date: 20 Jun 2007 01:24:02
From: Crazy Fred
Subject: Re: High Speed Shimmy
|
On Jun 20, 2:40 am, Troll Report <trollr...@rt.net > wrote:
> On 20 Jun 2007 01:25:58 GMT, jobst.bra...@stanfordalumni.org wrote:
>
> > Matt Grath writes:
>
> >> I know this is a well worn topic, but, I've experienced shimmy with
> >> my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
> >> riding the same hills for 15 years with no problems (for the past 8
> >> years on Cannondale, which, sadly developed a cracked frame). The
> >> shop tightened the spokes, which helped but did not solve the
> >> problem. Anyway, the point of the post is to poll folks - is this a
> >> Lightspeed issue?
>
> > You didn't say whether the shimmy occurs riding no-hands or whether
> > you experience it with hands on the bars.
>
> Troll-o-meter says: 3.2
>
> In what universe to you live in? One in which riding no-hands at 35-40mph
> is common enough that you'd think it's valid that this point should be
> clarified?
No one ever says maybe its a tire. I had two tires do the same.One
dating back to 11 years ago. And one just last month. Had the wheel
trued and it went away but came right back. So I said try another
tire. Fix.
|
| |
Date: 19 Jun 2007 20:27:45
From: jim beam
Subject: Re: High Speed Shimmy
|
mgrath@optonline.net wrote:
> I know this is a well worn topic, but, I've experienced shimmy with my
> new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
> same hills for 15 years with no problems (for the past 8 years on
> Cannondale, which, sadly developed a cracked frame). The shop
> tightened the spokes, which helped but did not solve the problem.
> Anyway, the point of the post is to poll folks - is this a Lightspeed
> issue?
> Thanks
> Matt
>
as said by the other posters, if it's a large frame, it could be a
lightspeed issue. /but/ tell us more about your wheels first. wheels
with better lateral stiffness do help mitigate this problem to a large
degree - try a different rear wheel with thicker [stiffer] drive side
spokes or stiffer rim. it affects the resonance, hopefully tuning the
wheels out of their harmonic with the frame.
|
| |
Date: 19 Jun 2007 18:29:52
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
>I know this is a well worn topic, but, I've experienced shimmy with my
> new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
> same hills for 15 years with no problems (for the past 8 years on
> Cannondale, which, sadly developed a cracked frame). The shop
> tightened the spokes, which helped but did not solve the problem.
> Anyway, the point of the post is to poll folks - is this a Lightspeed
> issue?
> Thanks
> Matt
Is this a large frame? It could then be a "Lightspeed issue" due to the
flexier tubes (flexier than your prior Cannondale). But there are so many
other variables, as pointed out in the FAQ that you've no doubt read. The
FAQ really is the definitive work on the subject.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| |
Date: 20 Jun 2007 01:25:58
From:
Subject: Re: High Speed Shimmy
|
Matt Grath writes:
> I know this is a well worn topic, but, I've experienced shimmy with
> my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
> riding the same hills for 15 years with no problems (for the past 8
> years on Cannondale, which, sadly developed a cracked frame). The
> shop tightened the spokes, which helped but did not solve the
> problem. Anyway, the point of the post is to poll folks - is this a
> Lightspeed issue?
You didn't say whether the shimmy occurs riding no-hands or whether
you experience it with hands on the bars. I am a bit suspicious when
you say spoke tightening had an effect. Unless the spokes were
rattlingly loose, spoke tension does not affect wheel stiffness.
That is, spoke preload does not affect elasticity.
You might save some time if you haven't seen the FAQ item by looking
it over:
http://www.sheldonbrown.com/brandt/shimmy.html
Jobst Brandt
|
| | |
Date: 20 Jun 2007 07:22:41
From: Tom Nakashima
Subject: Re: High Speed Shimmy
|
<jobst.brandt@stanfordalumni.org > wrote in message
news:46788226$0$14106$742ec2ed@news.sonic.net...
> Matt Grath writes:
>
>> I know this is a well worn topic, but, I've experienced shimmy with
>> my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
>> riding the same hills for 15 years with no problems (for the past 8
>> years on Cannondale, which, sadly developed a cracked frame). The
>> shop tightened the spokes, which helped but did not solve the
>> problem. Anyway, the point of the post is to poll folks - is this a
>> Lightspeed issue?
>
> You didn't say whether the shimmy occurs riding no-hands or whether
> you experience it with hands on the bars. I am a bit suspicious when
> you say spoke tightening had an effect. Unless the spokes were
> rattlingly loose, spoke tension does not affect wheel stiffness.
> That is, spoke preload does not affect elasticity.
>
> You might save some time if you haven't seen the FAQ item by looking
> it over:
>
> http://www.sheldonbrown.com/brandt/shimmy.html
>
> Jobst Brandt
I was experimenting with this shimmy descending Sand Hill rd.towards Old
LaHonda. I can generate a shimmy when I induce it with my muscular movement
without pedaling. No shimmy when I ride with no hands
and not pedaling. I also found out I can take out the shimmy by "pedaling"
on the decent after inducing it with muscular movement.
-tom
|
| | | |
Date: 25 Jun 2007 01:26:32
From:
Subject: Re: High Speed Shimmy
|
On Jun 23, 4:17 pm, jim beam <spamvor...@bad.example.net > wrote:
> Gary Young wrote:
> > On Sat, 23 Jun 2007 10:51:12 -0700, jim beam wrote:
> > <snip>
>
> >>>>> I wonder if "jim beam" would be so ready to snipe if he/she had to
> >>>>> use his/her real name on the postings?
> >>>> sure. utter bullshit doesn't need a nom-de-net.
> >>> Then why use one?
>
> >> because i want to!
>
> >>> Who or what are you afraid of?
>
> >> er, you?
>
> >> but that's not the point. reality is, handle has NOTHING to do with
> >> accuracy.
>
> > Sure, that's the reason scientific journals accept anonymous articles and
> > don't waste their time with a silly thing like peer review.
>
> anonymous writing goes back centuries gary. often for contentious
> issues. studied history or literature much have you?
>
Anonymity is sometimes a necessary evil, particularly when a scientist
faces the possibility of persecution. Nonetheless, in most cases
science progresses better without it, as is shown by the fact that
scientific journals require attribution. Is it your position that I'm
mistaken and that scientific journals don't insist on attribution? Do
you have any coherent position at all?
> as for "peer review", that's as much of a red herring coming from you as
> it is from jobst. he claims his book "has had much peer review over the
> last 20 years"http://groups.google.com/group/rec.bicycles.tech/msg/2b111c058444742b
> but it's still full of fundamental errors.
Even if it were true that peer review broke down in the case of
Jobst's book, what does that have to do with the issue I raised? Is it
or is it not true that scientists give greater importance to research
reports published in peer-reviewed journals? If so, how do you
reconcile that with your claim that only the text of the report should
matter and not matters like the identity and credentials of the author
or the reputation and authoritativeness of the journal?
> so what could possibly have
> gone wrong? [sic]
>
You don't know the meaning of "sic" or how to use it, do you?
> > After all,
> > what's peer review other than an extra layer of authority superimposed
> > over something that should be judged just by the bare text alone?
>
> authority? bare text? this is the point where your wheels fall off.
> again.
>
>
What does publication in a peer-reviewed journal provide that would be
otherwise be missing? -- the assurance that the research report has
been reviewed by authorities in the relevant field.
>
> >> the ridiculous way things are hereabouts,
> >>http://www.theflatearthsociety.org/would be given credence on r.b.t if
> >> they told you they were were stanford alumni.
|
| | | | |
Date: 24 Jun 2007 21:39:01
From: jim beam
Subject: Re: High Speed Shimmy
|
garyyoung3@gmail.com wrote:
> On Jun 23, 4:17 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Gary Young wrote:
>>> On Sat, 23 Jun 2007 10:51:12 -0700, jim beam wrote:
>>> <snip>
>>>>>>> I wonder if "jim beam" would be so ready to snipe if he/she had to
>>>>>>> use his/her real name on the postings?
>>>>>> sure. utter bullshit doesn't need a nom-de-net.
>>>>> Then why use one?
>>>> because i want to!
>>>>> Who or what are you afraid of?
>>>> er, you?
>>>> but that's not the point. reality is, handle has NOTHING to do with
>>>> accuracy.
>>> Sure, that's the reason scientific journals accept anonymous articles and
>>> don't waste their time with a silly thing like peer review.
>> anonymous writing goes back centuries gary. often for contentious
>> issues. studied history or literature much have you?
>>
>
> Anonymity is sometimes a necessary evil, particularly when a scientist
> faces the possibility of persecution. Nonetheless, in most cases
> science progresses better without it, as is shown by the fact that
> scientific journals require attribution. Is it your position that I'm
> mistaken and that scientific journals don't insist on attribution? Do
> you have any coherent position at all?
i've already stated my position. read it.
>
>> as for "peer review", that's as much of a red herring coming from you as
>> it is from jobst. he claims his book "has had much peer review over the
>> last 20 years"http://groups.google.com/group/rec.bicycles.tech/msg/2b111c058444742b
>> but it's still full of fundamental errors.
>
> Even if it were true that peer review broke down
it never "broke down", it was never undertaken! it was cited in defense
though. somewhat surprisingly.
> in the case of
> Jobst's book, what does that have to do with the issue I raised? Is it
> or is it not true that scientists give greater importance to research
> reports published in peer-reviewed journals? If so, how do you
> reconcile that with your claim that only the text of the report should
> matter and not matters like the identity and credentials of the author
> or the reputation and authoritativeness of the journal?
er, how about not building a career or getting funded based on publications?
>
>> so what could possibly have
>> gone wrong? [sic]
>>
>
> You don't know the meaning of "sic" or how to use it, do you?
er...
>
>>> After all,
>>> what's peer review other than an extra layer of authority superimposed
>>> over something that should be judged just by the bare text alone?
>> authority? bare text? this is the point where your wheels fall off.
>> again.
>>
>>
>
> What does publication in a peer-reviewed journal provide that would be
> otherwise be missing? -- the assurance that the research report has
> been reviewed by authorities in the relevant field.
when scientific review /is/ performed by peers, that would be correct.
in the case of jobst brandt however, he cites as "peer review" the
bleatings of sycophantic acolytes instead. and we wonder how nothing
gets changed!!!
>>>> the ridiculous way things are hereabouts,
>>>> http://www.theflatearthsociety.org/would be given credence on r.b.t if
>>>> they told you they were were stanford alumni.
>
>
|
| | | |
Date: 25 Jun 2007 01:05:24
From: datakoll
Subject: Re: High Speed Shimmy
|
On Jun 24, 2:17 pm, Johnny Sunset <sunsetss0...@yahoo.com > wrote:
> On Jun 24, 12:43 pm, datakoll aka gene daniels wrote:
>
> > if yawl want to use something try lethal dose of nocacaine
>
> dear gene,
>
> your suggestion was a good one, i will report back on [zzzz, clunk]
yeah. these hissy fits are a drag what with global warming. its like
passing in front of the intersection SUV. let the dolt go first. its
cheaper and safer.
people give me a rash for using color on email font!
but I don't use a/c or drive an auto to walmart. they do.
by the way. as I publish science and prediction on the internet,
everyone on AVAGADRO IV knows my name, datakoll is humor, like a
transistor or mtn pass in the TdF. the name shifts back and forth as
waves of reality-unreality pass thru it's meaning from cool to coal.
data to dada.
stupid no?
|
| | | |
Date: 24 Jun 2007 11:17:36
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 24, 12:43 pm, datakoll aka gene daniels wrote:
> if yawl want to use something try lethal dose of nocacaine
dear gene,
your suggestion was a good one, i will report back on [zzzz, clunk]
|
| | | |
Date: 23 Jun 2007 15:26:44
From: Jay Beattie
Subject: Re: High Speed Shimmy
|
On Jun 23, 1:17 pm, jim beam <spamvor...@bad.example.net > wrote:
> Gary Young wrote:
> > On Sat, 23 Jun 2007 10:51:12 -0700, jim beam wrote:
> > <snip>
<snip >
> anonymous writing goes back centuries gary. often for contentious
> issues. studied history or literature much have you?
This is true for fiction and political writers but not for scientific
writers whose bona fides come under careful scrutiny (except in
Korea). I mean really, could you imagine a serious scientific article
by "Hula Boy" or "Squishy Bear" or some nom de stupid like that. Only
on the internet could either get published -- in fact, they could get
published together with something like the "Hula Boy-Squishy Bear
bandwidth sucking phenomenon" or something scientific like that.
Internet science. It's the particle of the future! -- Jay Beattie.
|
| | | | |
Date: 23 Jun 2007 15:54:28
From: jim beam
Subject: Re: High Speed Shimmy
|
Jay Beattie wrote:
> On Jun 23, 1:17 pm, jim beam <spamvor...@bad.example.net> wrote:
>> Gary Young wrote:
>>> On Sat, 23 Jun 2007 10:51:12 -0700, jim beam wrote:
>>> <snip>
> <snip>
>
>> anonymous writing goes back centuries gary. often for contentious
>> issues. studied history or literature much have you?
>
> This is true for fiction and political writers but not for scientific
> writers whose bona fides come under careful scrutiny (except in
> Korea). I mean really, could you imagine a serious scientific article
> by "Hula Boy" or "Squishy Bear" or some nom de stupid like that. Only
> on the internet could either get published -- in fact, they could get
> published together with something like the "Hula Boy-Squishy Bear
> bandwidth sucking phenomenon" or something scientific like that.
> Internet science. It's the particle of the future! -- Jay Beattie.
>
look at it the other way - real name, cited education, misleading
garbage uttered. now what?
|
| | | | | |
Date: 23 Jun 2007 23:23:10
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
> look at it the other way - real name, cited education, misleading garbage
> uttered. now what?
Look at it this way. Real name, cited education, misleading garbage
uttered... since it's a real name, the reputation for garbage uttered, and
all the work done to prove it was garbage, was probably done long ago.
Fake names? I suppose, if someone kept the same fake name forever, the same
might be appropriate. But otherwise? And how do you know? Someone who posts
with a real name has a huge credibility advantage that way. Whatever
reputation they develop stays with them. Someone with a fake name? The
reputation stays with the fake name, not the person. Much less downside for
the person posting with the fake name to be truthful, or spend as much time
trying to make sure they have it right.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| | | | | | |
Date: 23 Jun 2007 17:05:10
From: jim beam
Subject: Re: High Speed Shimmy
|
Mike Jacoubowsky wrote:
>> look at it the other way - real name, cited education, misleading garbage
>> uttered. now what?
>
> Look at it this way. Real name, cited education, misleading garbage
> uttered... since it's a real name, the reputation for garbage uttered, and
> all the work done to prove it was garbage, was probably done long ago.
doesn't appear to be the case though does it. a bold face and bullying
seem to deceive the proletariat regardless of accuracy.
>
> Fake names? I suppose, if someone kept the same fake name forever, the same
> might be appropriate. But otherwise? And how do you know? Someone who posts
> with a real name has a huge credibility advantage that way.
not really. ad hominem is the m.o. of usenet. i spent some time
studying jobstian critics - and there have been a lot of them.
regardless of accuracy, they were bullied into disappearing. real names
got them nowhere.
> Whatever
> reputation they develop stays with them. Someone with a fake name? The
> reputation stays with the fake name, not the person. Much less downside for
> the person posting with the fake name to be truthful, or spend as much time
> trying to make sure they have it right.
>
but it doesn't mean they don't. however, they also get no credit, so no
up side either. c'est la vie. doesn't matter if you're not selling
anything though.
|
| | | |
Date: 21 Jun 2007 01:05:51
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
> I was experimenting with this shimmy descending Sand Hill rd.towards Old
> LaHonda. I can generate a shimmy when I induce it with my muscular
> movement without pedaling. No shimmy when I ride with no hands
> and not pedaling. I also found out I can take out the shimmy by "pedaling"
> on the decent after inducing it with muscular movement.
> -tom
As you have so capably demonstrated, shimmy is a function of the bike *and*
rider. It's a dynamic system, susceptible to far more variations from the
rider than from road conditions or even a component issue.
This comes up so often at my end of the business. We had one person who was
terrified there was something very wrong with her bike because she could get
it to shimmy/wobble at 38 mph descending this one particular road when there
was a crosswind on a cold day. *All* those things had to exist for the
shimmy to occur. And yet it was the bike at fault.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
|
| | | | |
Date: 20 Jun 2007 20:40:05
From: jim beam
Subject: Re: High Speed Shimmy
|
Mike Jacoubowsky wrote:
>> I was experimenting with this shimmy descending Sand Hill rd.towards Old
>> LaHonda. I can generate a shimmy when I induce it with my muscular
>> movement without pedaling. No shimmy when I ride with no hands
>> and not pedaling. I also found out I can take out the shimmy by "pedaling"
>> on the decent after inducing it with muscular movement.
>> -tom
>
> As you have so capably demonstrated, shimmy is a function of the bike *and*
> rider. It's a dynamic system, susceptible to far more variations from the
> rider than from road conditions or even a component issue.
>
> This comes up so often at my end of the business. We had one person who was
> terrified there was something very wrong with her bike because she could get
> it to shimmy/wobble at 38 mph descending this one particular road when there
> was a crosswind on a cold day. *All* those things had to exist for the
> shimmy to occur. And yet it was the bike at fault.
it is. bike shouldn't do it under any circumstances. the resonance of
the frame and wheels should be different, not coincident.
|
| | | | | |
Date: 21 Jun 2007 21:18:58
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
>> This comes up so often at my end of the business. We had one person who
>> was terrified there was something very wrong with her bike because she
>> could get it to shimmy/wobble at 38 mph descending this one particular
>> road when there was a crosswind on a cold day. *All* those things had to
>> exist for the shimmy to occur. And yet it was the bike at fault.
>
> it is. bike shouldn't do it under any circumstances. the resonance of
> the frame and wheels should be different, not coincident.
A bike is not stable without a rider on it. Do you actually disagree with
this? And, if you don't, do you understand the ramifications of it? Are you
suggesting that a shaking rider should have no effect on a bike's resistance
to shimmy?
--Mike--
Chain Reaction Bicycles
www.ChainReaction.com
|
| | | | | | |
Date: 26 Jun 2007 18:29:45
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 24, 11:33 pm, jim beam aka Kentucky Bourbon wrote:
> ...
> anyway, timmy boy, i'm off for a summer vacation soon....
Off to stalk Jobst Brandt as he rides the Alps? ;)
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | | | | | |
Date: 24 Jun 2007 09:13:10
From: Luns Tee
Subject: Re: High Speed Shimmy
|
In article <6XBei.2703$W_6.1094@newsread1.news.pas.earthlink.net >,
Mike Jacoubowsky <MikeJ@ChainReaction.com > wrote:
>A bike is not stable without a rider on it. Do you actually disagree with
>this?
You may find this video interesting:
http://ruina.tam.cornell.edu/research/topics/bicycle_mechanics/bicycle_stability.mov
-Luns
|
| | | | | | | |
Date: 24 Jun 2007 09:26:44
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <f5lcj6$2guv$1@agate.berkeley.edu >,
luns@mochi.EECS.Berkeley.EDU (Luns Tee) wrote:
> In article <6XBei.2703$W_6.1094@newsread1.news.pas.earthlink.net>,
> Mike Jacoubowsky <MikeJ@ChainReaction.com> wrote:
> >A bike is not stable without a rider on it. Do you actually disagree with
> >this?
>
> You may find this video interesting:
Note: I converted this to a TinyURL because it was long enough to get
line wrapped.
>http://tinyurl.com/262tel
Yes, I've seen very similar footage in the PBS documentary "The Bicycle"
as a demonstration of part of Jones's URB research. The bike in
question- which looked very very similar to that one- had steering
geometry designed to self correct against the gyroscopic force of the
front wheel. Basically the fork had been reversed to create a huge
geometric trail. The bike was so stable that it was unrideable- it was
barely possible to go around corners.
Jones's article with photos of his bikes. I hadn't seen this before.
http://www.phys.lsu.edu/faculty/gonzalez/Teaching/Phys7221/vol59no9p51_56
.pdf
or http://tinyurl.com/23722q
|
| | | | | | | | |
Date: 24 Jun 2007 12:04:34
From:
Subject: Re: High Speed Shimmy
|
On Sun, 24 Jun 2007 09:26:44 -0500, Tim McNamara
<timmcn@bitstream.net > wrote:
>In article <f5lcj6$2guv$1@agate.berkeley.edu>,
> luns@mochi.EECS.Berkeley.EDU (Luns Tee) wrote:
>
>> In article <6XBei.2703$W_6.1094@newsread1.news.pas.earthlink.net>,
>> Mike Jacoubowsky <MikeJ@ChainReaction.com> wrote:
>> >A bike is not stable without a rider on it. Do you actually disagree with
>> >this?
>>
>> You may find this video interesting:
>
>Note: I converted this to a TinyURL because it was long enough to get
>line wrapped.
>
>>http://tinyurl.com/262tel
>
>Yes, I've seen very similar footage in the PBS documentary "The Bicycle"
>as a demonstration of part of Jones's URB research. The bike in
>question- which looked very very similar to that one- had steering
>geometry designed to self correct against the gyroscopic force of the
>front wheel. Basically the fork had been reversed to create a huge
>geometric trail. The bike was so stable that it was unrideable- it was
>barely possible to go around corners.
>
>Jones's article with photos of his bikes. I hadn't seen this before.
>
>http://www.phys.lsu.edu/faculty/gonzalez/Teaching/Phys7221/vol59no9p51_56
>.pdf
>
>or http://tinyurl.com/23722q
Dear Tim & Luns,
Movie from Luns:
http://tinyurl.com/262tel
Professor Jones trying to construct unrideable bike from Tim:
http://www.phys.lsu.edu/faculty/gonzalez/Teaching/Phys7221/vol59no9p51_56.pdf
Professor Jones seems to support the movie that Luns linked to,
showing a riderless bicycle staying upright for quite a while when
pushed:
" . . . a [normal] bicycle pushed and released riderless will stay up
on its own, traveling in a long curve and finally collapsing after
about 20 seconds, compared to the 2 seconds it would take if static."
--page 51
The explanation seems to be that the gyroscopic forces are large
enough in relation to the small total mass of a riderless bike:
"The light, riderless bicycle is stabilized by gyroscopic action,
whereas the heavier ridden model is not--it requires constant rider
effort to maintain its stability."
--p. 51-2
Even greater stability can be gained by reversing the fork:
"(b) At left is URB III, whose reversed front forks give it great
stability when pushed and released riderless."
--page 52
Interestingly, Professor Jones found that old highwheelers were
surprisingly stable, falling at points 3 & 4 on his stability graph,
while two early "safety" bicycles at points 5 & 6 were closer to his
nearly unrideable bike.
Cheers,
Carl Fogel
|
| | | | | | | | | |
Date: 25 Jun 2007 08:54:42
From: Michael Warner
Subject: Re: High Speed Shimmy
|
On Sun, 24 Jun 2007 12:04:34 -0600, carlfogel@comcast.net wrote:
> Interestingly, Professor Jones found that old highwheelers were
> surprisingly stable
Penny farthings? I'd love to try one of those.
--
Home page: http://members.westnet.com.au/mvw
|
| | | | | | | | | | |
Date: 25 Jun 2007 02:25:45
From: Michael Press
Subject: Re: High Speed Shimmy
|
In article
<1jv12lgt74yc5.1dfsqnd3qq5ff.dlg@40tude.net >,
Michael Warner <mvw@westnet.com.au > wrote:
> On Sun, 24 Jun 2007 12:04:34 -0600, carlfogel@comcast.net wrote:
>
> > Interestingly, Professor Jones found that old highwheelers were
> > surprisingly stable
>
> Penny farthings? I'd love to try one of those.
They are unstable in a more important way. It is easy
to go over the bars. All the rider weight is within 20
degrees of the vertical from the big wheel, with little
mass holding down the back end.
--
Michael Press
|
| | | | | | | | | | |
Date: 24 Jun 2007 17:46:12
From:
Subject: Re: High Speed Shimmy
|
On Mon, 25 Jun 2007 08:54:42 +0930, Michael Warner
<mvw@westnet.com.au > wrote:
>On Sun, 24 Jun 2007 12:04:34 -0600, carlfogel@comcast.net wrote:
>
>> Interestingly, Professor Jones found that old highwheelers were
>> surprisingly stable
>
>Penny farthings? I'd love to try one of those.
Dear Michael,
Only $3k AU:
http://canberrabicyclemuseum.com.au/forsale.htm
Browse around that site and you might find someone on the same
continent with highwheeler connections.
Cheers,
Carl Fogel
|
| | | | | | |
Date: 21 Jun 2007 21:20:36
From: jim beam
Subject: Re: High Speed Shimmy
|
Mike Jacoubowsky wrote:
>>> This comes up so often at my end of the business. We had one person who
>>> was terrified there was something very wrong with her bike because she
>>> could get it to shimmy/wobble at 38 mph descending this one particular
>>> road when there was a crosswind on a cold day. *All* those things had to
>>> exist for the shimmy to occur. And yet it was the bike at fault.
>> it is. bike shouldn't do it under any circumstances. the resonance of
>> the frame and wheels should be different, not coincident.
>
> A bike is not stable without a rider on it. Do you actually disagree with
> this?
in that the contact patch of the tire trails behind the fork angle's
intersection with the road, yes it is inherently stable. in that the
spring constants of both frame and tires give resonant frequencies well
above any frequency that can gain any significant amplitude, yes, it is
inherently stable.
> And, if you don't, do you understand the ramifications of it?
you're working with incomplete information.
> Are you
> suggesting that a shaking rider should have no effect on a bike's resistance
> to shimmy?
the rider should not be able to make the bike shimmy. with rider load,
the resonance of the frame and of the wheels should not be coincident.
period. many old fashioned steel frames /do/ shimmy because their
torsional stiffness is not very high, and in the old days of undished
wheels, it wasn't as much of a problem, but now, with 10-speed
ultra-dished wheels, it's a big deal. if we can't have un-dished
wheels, we can have torsionally stiff frames where their designer has
paid attention to this stuff. no excuses.
|
| | | | | | | |
Date: 22 Jun 2007 05:24:33
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
>>>> This comes up so often at my end of the business. We had one person who
>>>> was terrified there was something very wrong with her bike because she
>>>> could get it to shimmy/wobble at 38 mph descending this one particular
>>>> road when there was a crosswind on a cold day. *All* those things had
>>>> to exist for the shimmy to occur. And yet it was the bike at fault.
>>> it is. bike shouldn't do it under any circumstances. the resonance of
>>> the frame and wheels should be different, not coincident.
>>
>> A bike is not stable without a rider on it. Do you actually disagree with
>> this?
>
> in that the contact patch of the tire trails behind the fork angle's
> intersection with the road, yes it is inherently stable.
So you could give the bike a push, without a rider on it, and it would go
exactly how far before falling over?
in that the
> spring constants of both frame and tires give resonant frequencies well
> above any frequency that can gain any significant amplitude, yes, it is
> inherently stable.
>
>> And, if you don't, do you understand the ramifications of it?
>
> you're working with incomplete information.
What information did I leave out?
>> Are you suggesting that a shaking rider should have no effect on a bike's
>> resistance to shimmy?
>
> the rider should not be able to make the bike shimmy. with rider load,
> the resonance of the frame and of the wheels should not be coincident.
> period. many old fashioned steel frames /do/ shimmy because their
> torsional stiffness is not very high, and in the old days of undished
> wheels, it wasn't as much of a problem, but now, with 10-speed
> ultra-dished wheels, it's a big deal. if we can't have un-dished wheels,
> we can have torsionally stiff frames where their designer has paid
> attention to this stuff. no excuses.
So you believe flimsy wheels are the culprit? I used to think so too. But
after changing out wheels (lighter wheels exchanged for much-beefier,
stiffer versions) for a number of people, without cure, that didn't appear
to be the answer. I had much better success by changing the position of the
handlebars.
That's not to say that large frames aren't far more prone to shimmy than
smaller ones. You're absolutely correct about that. But that wasn't the
issue for the particular case I referenced. I didn't include the frame size;
it was 56cm, center-to-top.
Oops, I left out one other piece of information. The person whose bike
shimmied that I mentioned also had to take one hand off the bars for the
shimmy to occur. So you've got *5* things that had to exist for her bike to
shimmy-
#1: Only on this one particular road
#2: Speed had to be 38mph
#3: One hand off the bars
#4: Crosswind
#5: Cold
So think about what I'm saying here. If it was warm, no shimmy. Hands on
bars, no shimmy. Any other road, including descents at 38mph, no shimmy.
Higher or lower speed, no shimmy. No crosswind, no shimmy. For the sake of
full disclosure, the only thing possibly unusual about this one stretch of
road is that it's perfectly straight for a fairly good distance. I think
that pretty much lays everything out on the table.
Still think it was a problem with the bike? (And yes, we did try different
wheels. She wouldn't consider changing her position on the bike, so we
couldn't test for that.)
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | | | | | | |
Date: 22 Jun 2007 08:37:54
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net >,
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote:
> >>>> This comes up so often at my end of the business. We had one
> >>>> person who was terrified there was something very wrong with her
> >>>> bike because she could get it to shimmy/wobble at 38 mph
> >>>> descending this one particular road when there was a crosswind
> >>>> on a cold day. *All* those things had to exist for the shimmy to
> >>>> occur. And yet it was the bike at fault.
> >>> it is. bike shouldn't do it under any circumstances. the
> >>> resonance of the frame and wheels should be different, not
> >>> coincident.
> >>
> >> A bike is not stable without a rider on it. Do you actually
> >> disagree with this?
> >
> > in that the contact patch of the tire trails behind the fork
> > angle's intersection with the road, yes it is inherently stable.
>
> So you could give the bike a push, without a rider on it, and it
> would go exactly how far before falling over?
>
> in that the
> > spring constants of both frame and tires give resonant frequencies
> > well above any frequency that can gain any significant amplitude,
> > yes, it is inherently stable.
> >
> >> And, if you don't, do you understand the ramifications of it?
> >
> > you're working with incomplete information.
>
> What information did I leave out?
You don't have jim's apperceptive mass. He can see subtle reasons for
these phenomena that are obscure to the rest of us mere mortals. You
see, jim was a metallurgist whereas you've only been a bike shop owner
for the past 30 years or so.
> >> Are you suggesting that a shaking rider should have no effect on a
> >> bike's resistance to shimmy?
> >
> > the rider should not be able to make the bike shimmy. with rider
> > load, the resonance of the frame and of the wheels should not be
> > coincident. period. many old fashioned steel frames /do/ shimmy
> > because their torsional stiffness is not very high, and in the old
> > days of undished wheels, it wasn't as much of a problem, but now,
> > with 10-speed ultra-dished wheels, it's a big deal. if we can't
> > have un-dished wheels, we can have torsionally stiff frames where
> > their designer has paid attention to this stuff. no excuses.
>
> So you believe flimsy wheels are the culprit? I used to think so too.
> But after changing out wheels (lighter wheels exchanged for
> much-beefier, stiffer versions) for a number of people, without cure,
> that didn't appear to be the answer. I had much better success by
> changing the position of the handlebars.
>
> That's not to say that large frames aren't far more prone to shimmy
> than smaller ones. You're absolutely correct about that. But that
> wasn't the issue for the particular case I referenced. I didn't
> include the frame size; it was 56cm, center-to-top.
>
> Oops, I left out one other piece of information. The person whose
> bike shimmied that I mentioned also had to take one hand off the bars
> for the shimmy to occur. So you've got *5* things that had to exist
> for her bike to shimmy-
>
> #1: Only on this one particular road
> #2: Speed had to be 38mph
> #3: One hand off the bars
> #4: Crosswind
> #5: Cold
>
> So think about what I'm saying here. If it was warm, no shimmy. Hands
> on bars, no shimmy. Any other road, including descents at 38mph, no
> shimmy. Higher or lower speed, no shimmy. No crosswind, no shimmy.
> For the sake of full disclosure, the only thing possibly unusual
> about this one stretch of road is that it's perfectly straight for a
> fairly good distance. I think that pretty much lays everything out on
> the table.
>
> Still think it was a problem with the bike? (And yes, we did try
> different wheels. She wouldn't consider changing her position on the
> bike, so we couldn't test for that.)
Now, Mike, you know that jim is the infallible APE (All Purpose Expert)
and that if he says the problem is that the rear wheel is too flexible,
then that's the problem. If you replace the rear wheel with a stiffer
wheel and the bike still shimmies, jim is still right- it's reality
that's wrong.
|
| | | | | | | | | |
Date: 23 Jun 2007 18:48:58
From: Patrick Lamb
Subject: Re: High Speed Shimmy
|
On Fri, 22 Jun 2007 08:37:54 -0500, Tim McNamara
<timmcn@bitstream.net > wrote:
>
>Now, Mike, you know that jim is the infallible APE (All Purpose Expert)
>and that if he says the problem is that the rear wheel is too flexible,
>then that's the problem. If you replace the rear wheel with a stiffer
>wheel and the bike still shimmies, jim is still right- it's reality
>that's wrong.
Just curious; wonder what would happen if you got jb and SMS in a room
together...?
Email address works as is.
|
| | | | | | | | | | |
Date: 24 Jun 2007 07:10:01
From: Michael Press
Subject: Re: High Speed Shimmy
|
In article
<n9cr73dmif6t2usjnivr3nk9fjgnes6fd3@4ax.com >,
Patrick Lamb <pdl678NOSPAM@comcast.net > wrote:
> On Fri, 22 Jun 2007 08:37:54 -0500, Tim McNamara
> <timmcn@bitstream.net> wrote:
> >
> >Now, Mike, you know that jim is the infallible APE (All Purpose Expert)
> >and that if he says the problem is that the rear wheel is too flexible,
> >then that's the problem. If you replace the rear wheel with a stiffer
> >wheel and the bike still shimmies, jim is still right- it's reality
> >that's wrong.
>
> Just curious; wonder what would happen if you got jb and SMS in a room
> together...?
Try to imagine all life as you know it stopping
instantaneously and every molecule in your body
exploding at the speed of light.
--
Michael Press
|
| | | | | | | | | |
Date: 22 Jun 2007 19:10:19
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>
>>>>>> This comes up so often at my end of the business. We had one
>>>>>> person who was terrified there was something very wrong with her
>>>>>> bike because she could get it to shimmy/wobble at 38 mph
>>>>>> descending this one particular road when there was a crosswind
>>>>>> on a cold day. *All* those things had to exist for the shimmy to
>>>>>> occur. And yet it was the bike at fault.
>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>> resonance of the frame and wheels should be different, not
>>>>> coincident.
>>>> A bike is not stable without a rider on it. Do you actually
>>>> disagree with this?
>>> in that the contact patch of the tire trails behind the fork
>>> angle's intersection with the road, yes it is inherently stable.
>> So you could give the bike a push, without a rider on it, and it
>> would go exactly how far before falling over?
>>
>> in that the
>>> spring constants of both frame and tires give resonant frequencies
>>> well above any frequency that can gain any significant amplitude,
>>> yes, it is inherently stable.
>>>
>>>> And, if you don't, do you understand the ramifications of it?
>>> you're working with incomplete information.
>> What information did I leave out?
>
> You don't have jim's apperceptive mass. He can see subtle reasons for
> these phenomena that are obscure to the rest of us mere mortals.
one thing's for sure: there's a helluva lot that's obscure to retards.
> You
> see, jim was a metallurgist whereas you've only been a bike shop owner
> for the past 30 years or so.
with all due respect to bike store owners, 30 years on the job doesn't
automatically make them scientists expert in analysis of this kind of
problem. just like window frame fitters turned psychologists aren't
automatically good at the most basic of math concepts.
>
>>>> Are you suggesting that a shaking rider should have no effect on a
>>>> bike's resistance to shimmy?
>>> the rider should not be able to make the bike shimmy. with rider
>>> load, the resonance of the frame and of the wheels should not be
>>> coincident. period. many old fashioned steel frames /do/ shimmy
>>> because their torsional stiffness is not very high, and in the old
>>> days of undished wheels, it wasn't as much of a problem, but now,
>>> with 10-speed ultra-dished wheels, it's a big deal. if we can't
>>> have un-dished wheels, we can have torsionally stiff frames where
>>> their designer has paid attention to this stuff. no excuses.
>> So you believe flimsy wheels are the culprit? I used to think so too.
>> But after changing out wheels (lighter wheels exchanged for
>> much-beefier, stiffer versions) for a number of people, without cure,
>> that didn't appear to be the answer. I had much better success by
>> changing the position of the handlebars.
>>
>> That's not to say that large frames aren't far more prone to shimmy
>> than smaller ones. You're absolutely correct about that. But that
>> wasn't the issue for the particular case I referenced. I didn't
>> include the frame size; it was 56cm, center-to-top.
>>
>> Oops, I left out one other piece of information. The person whose
>> bike shimmied that I mentioned also had to take one hand off the bars
>> for the shimmy to occur. So you've got *5* things that had to exist
>> for her bike to shimmy-
>
>> #1: Only on this one particular road
>> #2: Speed had to be 38mph
>> #3: One hand off the bars
>> #4: Crosswind
>> #5: Cold
>>
>> So think about what I'm saying here. If it was warm, no shimmy. Hands
>> on bars, no shimmy. Any other road, including descents at 38mph, no
>> shimmy. Higher or lower speed, no shimmy. No crosswind, no shimmy.
>> For the sake of full disclosure, the only thing possibly unusual
>> about this one stretch of road is that it's perfectly straight for a
>> fairly good distance. I think that pretty much lays everything out on
>> the table.
>>
>> Still think it was a problem with the bike? (And yes, we did try
>> different wheels. She wouldn't consider changing her position on the
>> bike, so we couldn't test for that.)
>
>
> Now, Mike, you know that jim is the infallible APE (All Purpose Expert)
> and that if he says the problem is that the rear wheel is too flexible,
> then that's the problem. If you replace the rear wheel with a stiffer
> wheel and the bike still shimmies, jim is still right- it's reality
> that's wrong.
how would you know? you think i'm lying when i say that 5000 > 1600, so
everything is bullshit to you. retard.
|
| | | | | | | | | | |
Date: 23 Jun 2007 00:24:40
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> > "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >
> >>>>>> This comes up so often at my end of the business. We had one
> >>>>>> person who was terrified there was something very wrong with
> >>>>>> her bike because she could get it to shimmy/wobble at 38 mph
> >>>>>> descending this one particular road when there was a crosswind
> >>>>>> on a cold day. *All* those things had to exist for the shimmy
> >>>>>> to occur. And yet it was the bike at fault.
> >>>>> it is. bike shouldn't do it under any circumstances. the
> >>>>> resonance of the frame and wheels should be different, not
> >>>>> coincident.
> >>>> A bike is not stable without a rider on it. Do you actually
> >>>> disagree with this?
> >>> in that the contact patch of the tire trails behind the fork
> >>> angle's intersection with the road, yes it is inherently stable.
> >> So you could give the bike a push, without a rider on it, and it
> >> would go exactly how far before falling over?
> >>
> >> in that the
> >>> spring constants of both frame and tires give resonant
> >>> frequencies well above any frequency that can gain any
> >>> significant amplitude, yes, it is inherently stable.
> >>>
> >>>> And, if you don't, do you understand the ramifications of it?
> >>> you're working with incomplete information.
> >> What information did I leave out?
> >
> > You don't have jim's apperceptive mass. He can see subtle reasons
> > for these phenomena that are obscure to the rest of us mere
> > mortals.
>
> one thing's for sure: there's a helluva lot that's obscure to
> retards.
Well, obscure to you anyway.
> > You see, jim was a metallurgist whereas you've only been a bike
> > shop owner for the past 30 years or so.
>
> with all due respect to bike store owners, 30 years on the job
> doesn't automatically make them scientists expert in analysis of this
> kind of problem. just like window frame fitters turned psychologists
> aren't automatically good at the most basic of math concepts.
That's "glazier" to you. :-) Of course, by the same token
metallurgists aren't automatically good at mechanical engineering- as
the mechanical engineers have been pointing out to you for years.
> >>>> Are you suggesting that a shaking rider should have no effect on
> >>>> a bike's resistance to shimmy?
> >>> the rider should not be able to make the bike shimmy. with rider
> >>> load, the resonance of the frame and of the wheels should not be
> >>> coincident. period. many old fashioned steel frames /do/ shimmy
> >>> because their torsional stiffness is not very high, and in the
> >>> old days of undished wheels, it wasn't as much of a problem, but
> >>> now, with 10-speed ultra-dished wheels, it's a big deal. if we
> >>> can't have un-dished wheels, we can have torsionally stiff frames
> >>> where their designer has paid attention to this stuff. no
> >>> excuses.
> >> So you believe flimsy wheels are the culprit? I used to think so
> >> too. But after changing out wheels (lighter wheels exchanged for
> >> much-beefier, stiffer versions) for a number of people, without
> >> cure, that didn't appear to be the answer. I had much better
> >> success by changing the position of the handlebars.
> >>
> >> That's not to say that large frames aren't far more prone to
> >> shimmy than smaller ones. You're absolutely correct about that.
> >> But that wasn't the issue for the particular case I referenced. I
> >> didn't include the frame size; it was 56cm, center-to-top.
> >>
> >> Oops, I left out one other piece of information. The person whose
> >> bike shimmied that I mentioned also had to take one hand off the
> >> bars for the shimmy to occur. So you've got *5* things that had to
> >> exist for her bike to shimmy-
> >
> >> #1: Only on this one particular road #2: Speed had to be 38mph #3:
> >> One hand off the bars #4: Crosswind #5: Cold
> >>
> >> So think about what I'm saying here. If it was warm, no shimmy.
> >> Hands on bars, no shimmy. Any other road, including descents at
> >> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind,
> >> no shimmy. For the sake of full disclosure, the only thing
> >> possibly unusual about this one stretch of road is that it's
> >> perfectly straight for a fairly good distance. I think that pretty
> >> much lays everything out on the table.
> >>
> >> Still think it was a problem with the bike? (And yes, we did try
> >> different wheels. She wouldn't consider changing her position on
> >> the bike, so we couldn't test for that.)
> >
> > Now, Mike, you know that jim is the infallible APE (All Purpose
> > Expert) and that if he says the problem is that the rear wheel is
> > too flexible, then that's the problem. If you replace the rear
> > wheel with a stiffer wheel and the bike still shimmies, jim is
> > still right- it's reality that's wrong.
>
> how would you know? you think i'm lying when i say that 5000 > 1600,
> so everything is bullshit to you. retard.
You're lying again, jim, just like you were back in that thread. You
keep coming up with different numbers- obviously you don't get the same
answer consistently when you add 2 + 2. I doubt your mathematics
abilities more and more. Or perhaps it's your memory.
|
| | | | | | | | | | | |
Date: 23 Jun 2007 06:23:15
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>
>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>> descending this one particular road when there was a crosswind
>>>>>>>> on a cold day. *All* those things had to exist for the shimmy
>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>> coincident.
>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>> disagree with this?
>>>>> in that the contact patch of the tire trails behind the fork
>>>>> angle's intersection with the road, yes it is inherently stable.
>>>> So you could give the bike a push, without a rider on it, and it
>>>> would go exactly how far before falling over?
>>>>
>>>> in that the
>>>>> spring constants of both frame and tires give resonant
>>>>> frequencies well above any frequency that can gain any
>>>>> significant amplitude, yes, it is inherently stable.
>>>>>
>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>> you're working with incomplete information.
>>>> What information did I leave out?
>>> You don't have jim's apperceptive mass. He can see subtle reasons
>>> for these phenomena that are obscure to the rest of us mere
>>> mortals.
>> one thing's for sure: there's a helluva lot that's obscure to
>> retards.
>
> Well, obscure to you anyway.
>
>>> You see, jim was a metallurgist whereas you've only been a bike
>>> shop owner for the past 30 years or so.
>> with all due respect to bike store owners, 30 years on the job
>> doesn't automatically make them scientists expert in analysis of this
>> kind of problem. just like window frame fitters turned psychologists
>> aren't automatically good at the most basic of math concepts.
>
> That's "glazier" to you. :-) Of course, by the same token
> metallurgists aren't automatically good at mechanical engineering- as
> the mechanical engineers have been pointing out to you for years.
funny. like it took a metallurgist to point out that the tensiometer
math in "the book" had omitted spoke stiffness - that's supposed to be
"mechanical engineering". but you'd already spotted that error hadn't
you timmy - you were just waiting for the right time to say something.
>
>>>>>> Are you suggesting that a shaking rider should have no effect on
>>>>>> a bike's resistance to shimmy?
>>>>> the rider should not be able to make the bike shimmy. with rider
>>>>> load, the resonance of the frame and of the wheels should not be
>>>>> coincident. period. many old fashioned steel frames /do/ shimmy
>>>>> because their torsional stiffness is not very high, and in the
>>>>> old days of undished wheels, it wasn't as much of a problem, but
>>>>> now, with 10-speed ultra-dished wheels, it's a big deal. if we
>>>>> can't have un-dished wheels, we can have torsionally stiff frames
>>>>> where their designer has paid attention to this stuff. no
>>>>> excuses.
>>>> So you believe flimsy wheels are the culprit? I used to think so
>>>> too. But after changing out wheels (lighter wheels exchanged for
>>>> much-beefier, stiffer versions) for a number of people, without
>>>> cure, that didn't appear to be the answer. I had much better
>>>> success by changing the position of the handlebars.
>>>>
>>>> That's not to say that large frames aren't far more prone to
>>>> shimmy than smaller ones. You're absolutely correct about that.
>>>> But that wasn't the issue for the particular case I referenced. I
>>>> didn't include the frame size; it was 56cm, center-to-top.
>>>>
>>>> Oops, I left out one other piece of information. The person whose
>>>> bike shimmied that I mentioned also had to take one hand off the
>>>> bars for the shimmy to occur. So you've got *5* things that had to
>>>> exist for her bike to shimmy-
>>>> #1: Only on this one particular road #2: Speed had to be 38mph #3:
>>>> One hand off the bars #4: Crosswind #5: Cold
>>>>
>>>> So think about what I'm saying here. If it was warm, no shimmy.
>>>> Hands on bars, no shimmy. Any other road, including descents at
>>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No crosswind,
>>>> no shimmy. For the sake of full disclosure, the only thing
>>>> possibly unusual about this one stretch of road is that it's
>>>> perfectly straight for a fairly good distance. I think that pretty
>>>> much lays everything out on the table.
>>>>
>>>> Still think it was a problem with the bike? (And yes, we did try
>>>> different wheels. She wouldn't consider changing her position on
>>>> the bike, so we couldn't test for that.)
>>> Now, Mike, you know that jim is the infallible APE (All Purpose
>>> Expert) and that if he says the problem is that the rear wheel is
>>> too flexible, then that's the problem. If you replace the rear
>>> wheel with a stiffer wheel and the bike still shimmies, jim is
>>> still right- it's reality that's wrong.
>> how would you know? you think i'm lying when i say that 5000 > 1600,
>> so everything is bullshit to you. retard.
>
> You're lying again, jim, just like you were back in that thread. You
> keep coming up with different numbers- obviously you don't get the same
> answer consistently when you add 2 + 2. I doubt your mathematics
> abilities more and more. Or perhaps it's your memory.
what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
you're an irredeemable fucking retard timmy!
***
dear mrs mcnamara
it is with regret that we must tell you to keep your son home for
another week's suspension again this semester. he has been fighting
with the other boys and is becoming increasingly disruptive in class.
in addition, as discussed at our last meeting, his grades continue to be
well below standard, and even with the remedial classes he's been
attending, he has shown no ability to catch up.
in consultation with his teachers and the school counselor therefore, it
is our opinion that academic frustration and taunting from the other
children are causing his behavior problems. in timmy's best interests
therefore, we will will be making arrangements for him to attend happy
valley retards school where his special needs can be better
accommodated. you will be contacted directly by happy valley's
admissions director, ms. u. gottabekiddingme, ph.d., and their learning
difficulties specialist, dr. i. v. ritalin, who will be supervising his
treatments.
|
| | | | | | | | | | | | |
Date: 23 Jun 2007 18:38:52
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> >>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >>>
> >>>>>>>> This comes up so often at my end of the business. We had one
> >>>>>>>> person who was terrified there was something very wrong with
> >>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
> >>>>>>>> descending this one particular road when there was a
> >>>>>>>> crosswind on a cold day. *All* those things had to exist for
> >>>>>>>> the shimmy to occur. And yet it was the bike at fault.
> >>>>>>> it is. bike shouldn't do it under any circumstances. the
> >>>>>>> resonance of the frame and wheels should be different, not
> >>>>>>> coincident.
> >>>>>> A bike is not stable without a rider on it. Do you actually
> >>>>>> disagree with this?
> >>>>> in that the contact patch of the tire trails behind the fork
> >>>>> angle's intersection with the road, yes it is inherently
> >>>>> stable.
> >>>> So you could give the bike a push, without a rider on it, and it
> >>>> would go exactly how far before falling over?
> >>>>
> >>>> in that the
> >>>>> spring constants of both frame and tires give resonant
> >>>>> frequencies well above any frequency that can gain any
> >>>>> significant amplitude, yes, it is inherently stable.
> >>>>>
> >>>>>> And, if you don't, do you understand the ramifications of it?
> >>>>> you're working with incomplete information.
> >>>> What information did I leave out?
> >>> You don't have jim's apperceptive mass. He can see subtle
> >>> reasons for these phenomena that are obscure to the rest of us
> >>> mere mortals.
> >> one thing's for sure: there's a helluva lot that's obscure to
> >> retards.
> >
> > Well, obscure to you anyway.
> >
> >>> You see, jim was a metallurgist whereas you've only been a bike
> >>> shop owner for the past 30 years or so.
> >> with all due respect to bike store owners, 30 years on the job
> >> doesn't automatically make them scientists expert in analysis of
> >> this kind of problem. just like window frame fitters turned
> >> psychologists aren't automatically good at the most basic of math
> >> concepts.
> >
> > That's "glazier" to you. :-) Of course, by the same token
> > metallurgists aren't automatically good at mechanical engineering-
> > as the mechanical engineers have been pointing out to you for
> > years.
>
> funny. like it took a metallurgist to point out that the tensiometer
> math in "the book" had omitted spoke stiffness - that's supposed to
> be "mechanical engineering". but you'd already spotted that error
> hadn't you timmy - you were just waiting for the right time to say
> something.
Nope, hadn't noticed. But since the issue had already been discussed by
Jobst and others long before you turned up in the newsgroup, I was aware
of it.
> >>>>>> Are you suggesting that a shaking rider should have no effect
> >>>>>> on a bike's resistance to shimmy?
> >>>>> the rider should not be able to make the bike shimmy. with
> >>>>> rider load, the resonance of the frame and of the wheels should
> >>>>> not be coincident. period. many old fashioned steel frames
> >>>>> /do/ shimmy because their torsional stiffness is not very high,
> >>>>> and in the old days of undished wheels, it wasn't as much of a
> >>>>> problem, but now, with 10-speed ultra-dished wheels, it's a big
> >>>>> deal. if we can't have un-dished wheels, we can have
> >>>>> torsionally stiff frames where their designer has paid
> >>>>> attention to this stuff. no excuses.
> >>>> So you believe flimsy wheels are the culprit? I used to think so
> >>>> too. But after changing out wheels (lighter wheels exchanged for
> >>>> much-beefier, stiffer versions) for a number of people, without
> >>>> cure, that didn't appear to be the answer. I had much better
> >>>> success by changing the position of the handlebars.
> >>>>
> >>>> That's not to say that large frames aren't far more prone to
> >>>> shimmy than smaller ones. You're absolutely correct about that.
> >>>> But that wasn't the issue for the particular case I referenced.
> >>>> I didn't include the frame size; it was 56cm, center-to-top.
> >>>>
> >>>> Oops, I left out one other piece of information. The person
> >>>> whose bike shimmied that I mentioned also had to take one hand
> >>>> off the bars for the shimmy to occur. So you've got *5* things
> >>>> that had to exist for her bike to shimmy- #1: Only on this one
> >>>> particular road #2: Speed had to be 38mph #3: One hand off the
> >>>> bars #4: Crosswind #5: Cold
> >>>>
> >>>> So think about what I'm saying here. If it was warm, no shimmy.
> >>>> Hands on bars, no shimmy. Any other road, including descents at
> >>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No
> >>>> crosswind, no shimmy. For the sake of full disclosure, the only
> >>>> thing possibly unusual about this one stretch of road is that
> >>>> it's perfectly straight for a fairly good distance. I think that
> >>>> pretty much lays everything out on the table.
> >>>>
> >>>> Still think it was a problem with the bike? (And yes, we did try
> >>>> different wheels. She wouldn't consider changing her position on
> >>>> the bike, so we couldn't test for that.)
> >>> Now, Mike, you know that jim is the infallible APE (All Purpose
> >>> Expert) and that if he says the problem is that the rear wheel is
> >>> too flexible, then that's the problem. If you replace the rear
> >>> wheel with a stiffer wheel and the bike still shimmies, jim is
> >>> still right- it's reality that's wrong.
> >> how would you know? you think i'm lying when i say that 5000 >
> >> 1600, so everything is bullshit to you. retard.
> >
> > You're lying again, jim, just like you were back in that thread.
> > You keep coming up with different numbers- obviously you don't get
> > the same answer consistently when you add 2 + 2. I doubt your
> > mathematics abilities more and more. Or perhaps it's your memory.
>
> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
> you're an irredeemable fucking retard timmy!
Better that than a liar, jim.
> ***
>
> dear mrs mcnamara
>
> it is with regret that we must tell you to keep your son home for
> another week's suspension again this semester. he has been fighting
> with the other boys and is becoming increasingly disruptive in class.
> in addition, as discussed at our last meeting, his grades continue to
> be well below standard, and even with the remedial classes he's been
> attending, he has shown no ability to catch up.
>
> in consultation with his teachers and the school counselor therefore,
> it is our opinion that academic frustration and taunting from the
> other children are causing his behavior problems. in timmy's best
> interests therefore, we will will be making arrangements for him to
> attend happy valley retards school where his special needs can be
> better accommodated. you will be contacted directly by happy
> valley's admissions director, ms. u. gottabekiddingme, ph.d., and
> their learning difficulties specialist, dr. i. v. ritalin, who will
> be supervising his treatments.
Was this supposed to be cutting? Or amusing? Or anything other than
pathetic?
|
| | | | | | | | | | | | | |
Date: 23 Jun 2007 17:27:10
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>
>>>>>>>>>> This comes up so often at my end of the business. We had one
>>>>>>>>>> person who was terrified there was something very wrong with
>>>>>>>>>> her bike because she could get it to shimmy/wobble at 38 mph
>>>>>>>>>> descending this one particular road when there was a
>>>>>>>>>> crosswind on a cold day. *All* those things had to exist for
>>>>>>>>>> the shimmy to occur. And yet it was the bike at fault.
>>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>>> coincident.
>>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>>> disagree with this?
>>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>>> angle's intersection with the road, yes it is inherently
>>>>>>> stable.
>>>>>> So you could give the bike a push, without a rider on it, and it
>>>>>> would go exactly how far before falling over?
>>>>>>
>>>>>> in that the
>>>>>>> spring constants of both frame and tires give resonant
>>>>>>> frequencies well above any frequency that can gain any
>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>
>>>>>>>> And, if you don't, do you understand the ramifications of it?
>>>>>>> you're working with incomplete information.
>>>>>> What information did I leave out?
>>>>> You don't have jim's apperceptive mass. He can see subtle
>>>>> reasons for these phenomena that are obscure to the rest of us
>>>>> mere mortals.
>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>> retards.
>>> Well, obscure to you anyway.
>>>
>>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>>> shop owner for the past 30 years or so.
>>>> with all due respect to bike store owners, 30 years on the job
>>>> doesn't automatically make them scientists expert in analysis of
>>>> this kind of problem. just like window frame fitters turned
>>>> psychologists aren't automatically good at the most basic of math
>>>> concepts.
>>> That's "glazier" to you. :-) Of course, by the same token
>>> metallurgists aren't automatically good at mechanical engineering-
>>> as the mechanical engineers have been pointing out to you for
>>> years.
>> funny. like it took a metallurgist to point out that the tensiometer
>> math in "the book" had omitted spoke stiffness - that's supposed to
>> be "mechanical engineering". but you'd already spotted that error
>> hadn't you timmy - you were just waiting for the right time to say
>> something.
>
> Nope, hadn't noticed. But since the issue had already been discussed by
> Jobst and others long before you turned up in the newsgroup, I was aware
> of it.
really, so after this so-called "discussion of which you were previously
aware", you were still deceived. doesn't say much for your mental
acuity. does it timmy.
>
>>>>>>>> Are you suggesting that a shaking rider should have no effect
>>>>>>>> on a bike's resistance to shimmy?
>>>>>>> the rider should not be able to make the bike shimmy. with
>>>>>>> rider load, the resonance of the frame and of the wheels should
>>>>>>> not be coincident. period. many old fashioned steel frames
>>>>>>> /do/ shimmy because their torsional stiffness is not very high,
>>>>>>> and in the old days of undished wheels, it wasn't as much of a
>>>>>>> problem, but now, with 10-speed ultra-dished wheels, it's a big
>>>>>>> deal. if we can't have un-dished wheels, we can have
>>>>>>> torsionally stiff frames where their designer has paid
>>>>>>> attention to this stuff. no excuses.
>>>>>> So you believe flimsy wheels are the culprit? I used to think so
>>>>>> too. But after changing out wheels (lighter wheels exchanged for
>>>>>> much-beefier, stiffer versions) for a number of people, without
>>>>>> cure, that didn't appear to be the answer. I had much better
>>>>>> success by changing the position of the handlebars.
>>>>>>
>>>>>> That's not to say that large frames aren't far more prone to
>>>>>> shimmy than smaller ones. You're absolutely correct about that.
>>>>>> But that wasn't the issue for the particular case I referenced.
>>>>>> I didn't include the frame size; it was 56cm, center-to-top.
>>>>>>
>>>>>> Oops, I left out one other piece of information. The person
>>>>>> whose bike shimmied that I mentioned also had to take one hand
>>>>>> off the bars for the shimmy to occur. So you've got *5* things
>>>>>> that had to exist for her bike to shimmy- #1: Only on this one
>>>>>> particular road #2: Speed had to be 38mph #3: One hand off the
>>>>>> bars #4: Crosswind #5: Cold
>>>>>>
>>>>>> So think about what I'm saying here. If it was warm, no shimmy.
>>>>>> Hands on bars, no shimmy. Any other road, including descents at
>>>>>> 38mph, no shimmy. Higher or lower speed, no shimmy. No
>>>>>> crosswind, no shimmy. For the sake of full disclosure, the only
>>>>>> thing possibly unusual about this one stretch of road is that
>>>>>> it's perfectly straight for a fairly good distance. I think that
>>>>>> pretty much lays everything out on the table.
>>>>>>
>>>>>> Still think it was a problem with the bike? (And yes, we did try
>>>>>> different wheels. She wouldn't consider changing her position on
>>>>>> the bike, so we couldn't test for that.)
>>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
>>>>> Expert) and that if he says the problem is that the rear wheel is
>>>>> too flexible, then that's the problem. If you replace the rear
>>>>> wheel with a stiffer wheel and the bike still shimmies, jim is
>>>>> still right- it's reality that's wrong.
>>>> how would you know? you think i'm lying when i say that 5000 >
>>>> 1600, so everything is bullshit to you. retard.
>>> You're lying again, jim, just like you were back in that thread.
>>> You keep coming up with different numbers- obviously you don't get
>>> the same answer consistently when you add 2 + 2. I doubt your
>>> mathematics abilities more and more. Or perhaps it's your memory.
>> what, "different numbers" like 5000 > 1600 as opposed to 1600 < 5000?
>> you're an irredeemable fucking retard timmy!
>
> Better that than a liar, jim.
so a liar is one who says something you're too dense to comprehend?
you're a fucking retard timmy.
>
>> ***
>>
>> dear mrs mcnamara
>>
>> it is with regret that we must tell you to keep your son home for
>> another week's suspension again this semester. he has been fighting
>> with the other boys and is becoming increasingly disruptive in class.
>> in addition, as discussed at our last meeting, his grades continue to
>> be well below standard, and even with the remedial classes he's been
>> attending, he has shown no ability to catch up.
>>
>> in consultation with his teachers and the school counselor therefore,
>> it is our opinion that academic frustration and taunting from the
>> other children are causing his behavior problems. in timmy's best
>> interests therefore, we will will be making arrangements for him to
>> attend happy valley retards school where his special needs can be
>> better accommodated. you will be contacted directly by happy
>> valley's admissions director, ms. u. gottabekiddingme, ph.d., and
>> their learning difficulties specialist, dr. i. v. ritalin, who will
>> be supervising his treatments.
>
> Was this supposed to be cutting? Or amusing? Or anything other than
> pathetic?
no, it's illustrative of how retards get into psychology - they get
exposed to it young.
|
| | | | | | | | | | | | | | |
Date: 23 Jun 2007 23:40:06
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> >>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >>>>>
> >>>>>>>>>> This comes up so often at my end of the business. We had
> >>>>>>>>>> one person who was terrified there was something very
> >>>>>>>>>> wrong with her bike because she could get it to
> >>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
> >>>>>>>>>> road when there was a crosswind on a cold day. *All* those
> >>>>>>>>>> things had to exist for the shimmy to occur. And yet it
> >>>>>>>>>> was the bike at fault.
> >>>>>>>>> it is. bike shouldn't do it under any circumstances. the
> >>>>>>>>> resonance of the frame and wheels should be different, not
> >>>>>>>>> coincident.
> >>>>>>>> A bike is not stable without a rider on it. Do you actually
> >>>>>>>> disagree with this?
> >>>>>>> in that the contact patch of the tire trails behind the fork
> >>>>>>> angle's intersection with the road, yes it is inherently
> >>>>>>> stable.
> >>>>>> So you could give the bike a push, without a rider on it, and
> >>>>>> it would go exactly how far before falling over?
> >>>>>>
> >>>>>> in that the
> >>>>>>> spring constants of both frame and tires give resonant
> >>>>>>> frequencies well above any frequency that can gain any
> >>>>>>> significant amplitude, yes, it is inherently stable.
> >>>>>>>
> >>>>>>>> And, if you don't, do you understand the ramifications of
> >>>>>>>> it?
> >>>>>>> you're working with incomplete information.
> >>>>>> What information did I leave out?
> >>>>> You don't have jim's apperceptive mass. He can see subtle
> >>>>> reasons for these phenomena that are obscure to the rest of us
> >>>>> mere mortals.
> >>>> one thing's for sure: there's a helluva lot that's obscure to
> >>>> retards.
> >>> Well, obscure to you anyway.
> >>>
> >>>>> You see, jim was a metallurgist whereas you've only been a bike
> >>>>> shop owner for the past 30 years or so.
> >>>> with all due respect to bike store owners, 30 years on the job
> >>>> doesn't automatically make them scientists expert in analysis of
> >>>> this kind of problem. just like window frame fitters turned
> >>>> psychologists aren't automatically good at the most basic of
> >>>> math concepts.
> >>> That's "glazier" to you. :-) Of course, by the same token
> >>> metallurgists aren't automatically good at mechanical
> >>> engineering- as the mechanical engineers have been pointing out
> >>> to you for years.
> >> funny. like it took a metallurgist to point out that the
> >> tensiometer math in "the book" had omitted spoke stiffness -
> >> that's supposed to be "mechanical engineering". but you'd already
> >> spotted that error hadn't you timmy - you were just waiting for
> >> the right time to say something.
> >
> > Nope, hadn't noticed. But since the issue had already been
> > discussed by Jobst and others long before you turned up in the
> > newsgroup, I was aware of it.
>
> really, so after this so-called "discussion of which you were
> previously aware", you were still deceived. doesn't say much for
> your mental acuity. does it timmy.
I wrote that poorly. I hadn't noticed the spoke stiffness issue when I
read "The Bicycle Wheel" for the first time or two. Once I started
participating in the newsgroup, ca. 1993, the issue was under discussion
somewhere around that time. Joe Riel and Tuns Lee made it definitive
later- and, as you don't bother to note, those proofs were accepted.
You on the other had, can't be bothered to provide actual proof or even
to participate in a discussion of the advanced math involved. You
notably disappear when those discussions happen, no doubt so that you
don't disclose the fact that you haven't got a clue.
> >>>>>>>> Are you suggesting that a shaking rider should have no
> >>>>>>>> effect on a bike's resistance to shimmy?
> >>>>>>> the rider should not be able to make the bike shimmy. with
> >>>>>>> rider load, the resonance of the frame and of the wheels
> >>>>>>> should not be coincident. period. many old fashioned steel
> >>>>>>> frames /do/ shimmy because their torsional stiffness is not
> >>>>>>> very high, and in the old days of undished wheels, it wasn't
> >>>>>>> as much of a problem, but now, with 10-speed ultra-dished
> >>>>>>> wheels, it's a big deal. if we can't have un-dished wheels,
> >>>>>>> we can have torsionally stiff frames where their designer has
> >>>>>>> paid attention to this stuff. no excuses.
> >>>>>> So you believe flimsy wheels are the culprit? I used to think
> >>>>>> so too. But after changing out wheels (lighter wheels
> >>>>>> exchanged for much-beefier, stiffer versions) for a number of
> >>>>>> people, without cure, that didn't appear to be the answer. I
> >>>>>> had much better success by changing the position of the
> >>>>>> handlebars.
> >>>>>>
> >>>>>> That's not to say that large frames aren't far more prone to
> >>>>>> shimmy than smaller ones. You're absolutely correct about
> >>>>>> that. But that wasn't the issue for the particular case I
> >>>>>> referenced. I didn't include the frame size; it was 56cm,
> >>>>>> center-to-top.
> >>>>>>
> >>>>>> Oops, I left out one other piece of information. The person
> >>>>>> whose bike shimmied that I mentioned also had to take one hand
> >>>>>> off the bars for the shimmy to occur. So you've got *5* things
> >>>>>> that had to exist for her bike to shimmy- #1: Only on this one
> >>>>>> particular road #2: Speed had to be 38mph #3: One hand off the
> >>>>>> bars #4: Crosswind #5: Cold
> >>>>>>
> >>>>>> So think about what I'm saying here. If it was warm, no
> >>>>>> shimmy. Hands on bars, no shimmy. Any other road, including
> >>>>>> descents at 38mph, no shimmy. Higher or lower speed, no
> >>>>>> shimmy. No crosswind, no shimmy. For the sake of full
> >>>>>> disclosure, the only thing possibly unusual about this one
> >>>>>> stretch of road is that it's perfectly straight for a fairly
> >>>>>> good distance. I think that pretty much lays everything out on
> >>>>>> the table.
> >>>>>>
> >>>>>> Still think it was a problem with the bike? (And yes, we did
> >>>>>> try different wheels. She wouldn't consider changing her
> >>>>>> position on the bike, so we couldn't test for that.)
> >>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
> >>>>> Expert) and that if he says the problem is that the rear wheel
> >>>>> is too flexible, then that's the problem. If you replace the
> >>>>> rear wheel with a stiffer wheel and the bike still shimmies,
> >>>>> jim is still right- it's reality that's wrong.
> >>>> how would you know? you think i'm lying when i say that 5000 >
> >>>> 1600, so everything is bullshit to you. retard.
> >>> You're lying again, jim, just like you were back in that thread.
> >>> You keep coming up with different numbers- obviously you don't
> >>> get the same answer consistently when you add 2 + 2. I doubt
> >>> your mathematics abilities more and more. Or perhaps it's your
> >>> memory.
> >> what, "different numbers" like 5000 > 1600 as opposed to 1600 <
> >> 5000? you're an irredeemable fucking retard timmy!
> >
> > Better that than a liar, jim.
>
> so a liar is one who says something you're too dense to comprehend?
> you're a fucking retard timmy.
No, jim, a liar is a person who doesn't tell the truth. Perhaps your
vaunted intelligence needs some work if you can't understand these
simple concepts.
> >> ***
> >>
> >> dear mrs mcnamara
> >>
> >> it is with regret that we must tell you to keep your son home for
> >> another week's suspension again this semester. he has been
> >> fighting with the other boys and is becoming increasingly
> >> disruptive in class. in addition, as discussed at our last
> >> meeting, his grades continue to be well below standard, and even
> >> with the remedial classes he's been attending, he has shown no
> >> ability to catch up.
> >>
> >> in consultation with his teachers and the school counselor
> >> therefore, it is our opinion that academic frustration and
> >> taunting from the other children are causing his behavior
> >> problems. in timmy's best interests therefore, we will will be
> >> making arrangements for him to attend happy valley retards school
> >> where his special needs can be better accommodated. you will be
> >> contacted directly by happy valley's admissions director, ms. u.
> >> gottabekiddingme, ph.d., and their learning difficulties
> >> specialist, dr. i. v. ritalin, who will be supervising his
> >> treatments.
> >
> > Was this supposed to be cutting? Or amusing? Or anything other
> > than pathetic?
>
> no, it's illustrative of how retards get into psychology - they get
> exposed to it young.
You remain short of a clue jim. And obviously you have not been able to
comprehend Gaussian distributions. Again, such a simple concept. I am
starting to think that you are lying about being smarter than me.
|
| | | | | | | | | | | | | | | |
Date: 23 Jun 2007 22:46:40
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> Tim McNamara wrote:
>>>>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>>>
>>>>>>>>>>>> This comes up so often at my end of the business. We had
>>>>>>>>>>>> one person who was terrified there was something very
>>>>>>>>>>>> wrong with her bike because she could get it to
>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
>>>>>>>>>>>> road when there was a crosswind on a cold day. *All* those
>>>>>>>>>>>> things had to exist for the shimmy to occur. And yet it
>>>>>>>>>>>> was the bike at fault.
>>>>>>>>>>> it is. bike shouldn't do it under any circumstances. the
>>>>>>>>>>> resonance of the frame and wheels should be different, not
>>>>>>>>>>> coincident.
>>>>>>>>>> A bike is not stable without a rider on it. Do you actually
>>>>>>>>>> disagree with this?
>>>>>>>>> in that the contact patch of the tire trails behind the fork
>>>>>>>>> angle's intersection with the road, yes it is inherently
>>>>>>>>> stable.
>>>>>>>> So you could give the bike a push, without a rider on it, and
>>>>>>>> it would go exactly how far before falling over?
>>>>>>>>
>>>>>>>> in that the
>>>>>>>>> spring constants of both frame and tires give resonant
>>>>>>>>> frequencies well above any frequency that can gain any
>>>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>>>
>>>>>>>>>> And, if you don't, do you understand the ramifications of
>>>>>>>>>> it?
>>>>>>>>> you're working with incomplete information.
>>>>>>>> What information did I leave out?
>>>>>>> You don't have jim's apperceptive mass. He can see subtle
>>>>>>> reasons for these phenomena that are obscure to the rest of us
>>>>>>> mere mortals.
>>>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>>>> retards.
>>>>> Well, obscure to you anyway.
>>>>>
>>>>>>> You see, jim was a metallurgist whereas you've only been a bike
>>>>>>> shop owner for the past 30 years or so.
>>>>>> with all due respect to bike store owners, 30 years on the job
>>>>>> doesn't automatically make them scientists expert in analysis of
>>>>>> this kind of problem. just like window frame fitters turned
>>>>>> psychologists aren't automatically good at the most basic of
>>>>>> math concepts.
>>>>> That's "glazier" to you. :-) Of course, by the same token
>>>>> metallurgists aren't automatically good at mechanical
>>>>> engineering- as the mechanical engineers have been pointing out
>>>>> to you for years.
>>>> funny. like it took a metallurgist to point out that the
>>>> tensiometer math in "the book" had omitted spoke stiffness -
>>>> that's supposed to be "mechanical engineering". but you'd already
>>>> spotted that error hadn't you timmy - you were just waiting for
>>>> the right time to say something.
>>> Nope, hadn't noticed. But since the issue had already been
>>> discussed by Jobst and others long before you turned up in the
>>> newsgroup, I was aware of it.
>> really, so after this so-called "discussion of which you were
>> previously aware", you were still deceived. doesn't say much for
>> your mental acuity. does it timmy.
>
> I wrote that poorly. I hadn't noticed the spoke stiffness issue when I
> read "The Bicycle Wheel" for the first time or two. Once I started
> participating in the newsgroup, ca. 1993, the issue was under discussion
> somewhere around that time.
and unresolved.
> Joe Riel and Tuns Lee made it definitive
> later-
yes, after i raised it.
> and, as you don't bother to note, those proofs were accepted.
er, were we discussing specifics? i thought we were just discussing
your retardation.
> You on the other had, can't be bothered to provide actual proof or even
> to participate in a discussion of the advanced math involved.
you know, for a retard that doesn't know enough math to tell whether
5000 > 1600 or 1600 < 5000, that's pretty fucking rich. where were you
on the "compression spoke" thread recently? you could have made your
usual enlightening contributions to our engineering horizons and
explained on how it was impossible to... oh, wait, you didn't because
you're a fucking retard and don't understand. my bad.
> You
> notably disappear when those discussions happen, no doubt so that you
> don't disclose the fact that you haven't got a clue.
oh my! busted by the retard! guess i'd better quit my day job then!
>
>>>>>>>>>> Are you suggesting that a shaking rider should have no
>>>>>>>>>> effect on a bike's resistance to shimmy?
>>>>>>>>> the rider should not be able to make the bike shimmy. with
>>>>>>>>> rider load, the resonance of the frame and of the wheels
>>>>>>>>> should not be coincident. period. many old fashioned steel
>>>>>>>>> frames /do/ shimmy because their torsional stiffness is not
>>>>>>>>> very high, and in the old days of undished wheels, it wasn't
>>>>>>>>> as much of a problem, but now, with 10-speed ultra-dished
>>>>>>>>> wheels, it's a big deal. if we can't have un-dished wheels,
>>>>>>>>> we can have torsionally stiff frames where their designer has
>>>>>>>>> paid attention to this stuff. no excuses.
>>>>>>>> So you believe flimsy wheels are the culprit? I used to think
>>>>>>>> so too. But after changing out wheels (lighter wheels
>>>>>>>> exchanged for much-beefier, stiffer versions) for a number of
>>>>>>>> people, without cure, that didn't appear to be the answer. I
>>>>>>>> had much better success by changing the position of the
>>>>>>>> handlebars.
>>>>>>>>
>>>>>>>> That's not to say that large frames aren't far more prone to
>>>>>>>> shimmy than smaller ones. You're absolutely correct about
>>>>>>>> that. But that wasn't the issue for the particular case I
>>>>>>>> referenced. I didn't include the frame size; it was 56cm,
>>>>>>>> center-to-top.
>>>>>>>>
>>>>>>>> Oops, I left out one other piece of information. The person
>>>>>>>> whose bike shimmied that I mentioned also had to take one hand
>>>>>>>> off the bars for the shimmy to occur. So you've got *5* things
>>>>>>>> that had to exist for her bike to shimmy- #1: Only on this one
>>>>>>>> particular road #2: Speed had to be 38mph #3: One hand off the
>>>>>>>> bars #4: Crosswind #5: Cold
>>>>>>>>
>>>>>>>> So think about what I'm saying here. If it was warm, no
>>>>>>>> shimmy. Hands on bars, no shimmy. Any other road, including
>>>>>>>> descents at 38mph, no shimmy. Higher or lower speed, no
>>>>>>>> shimmy. No crosswind, no shimmy. For the sake of full
>>>>>>>> disclosure, the only thing possibly unusual about this one
>>>>>>>> stretch of road is that it's perfectly straight for a fairly
>>>>>>>> good distance. I think that pretty much lays everything out on
>>>>>>>> the table.
>>>>>>>>
>>>>>>>> Still think it was a problem with the bike? (And yes, we did
>>>>>>>> try different wheels. She wouldn't consider changing her
>>>>>>>> position on the bike, so we couldn't test for that.)
>>>>>>> Now, Mike, you know that jim is the infallible APE (All Purpose
>>>>>>> Expert) and that if he says the problem is that the rear wheel
>>>>>>> is too flexible, then that's the problem. If you replace the
>>>>>>> rear wheel with a stiffer wheel and the bike still shimmies,
>>>>>>> jim is still right- it's reality that's wrong.
>>>>>> how would you know? you think i'm lying when i say that 5000 >
>>>>>> 1600, so everything is bullshit to you. retard.
>>>>> You're lying again, jim, just like you were back in that thread.
>>>>> You keep coming up with different numbers- obviously you don't
>>>>> get the same answer consistently when you add 2 + 2. I doubt
>>>>> your mathematics abilities more and more. Or perhaps it's your
>>>>> memory.
>>>> what, "different numbers" like 5000 > 1600 as opposed to 1600 <
>>>> 5000? you're an irredeemable fucking retard timmy!
>>> Better that than a liar, jim.
>> so a liar is one who says something you're too dense to comprehend?
>> you're a fucking retard timmy.
>
> No, jim, a liar is a person who doesn't tell the truth. Perhaps your
> vaunted intelligence needs some work if you can't understand these
> simple concepts.
so why do you call me a liar then retard?
>
>>>> ***
>>>>
>>>> dear mrs mcnamara
>>>>
>>>> it is with regret that we must tell you to keep your son home for
>>>> another week's suspension again this semester. he has been
>>>> fighting with the other boys and is becoming increasingly
>>>> disruptive in class. in addition, as discussed at our last
>>>> meeting, his grades continue to be well below standard, and even
>>>> with the remedial classes he's been attending, he has shown no
>>>> ability to catch up.
>>>>
>>>> in consultation with his teachers and the school counselor
>>>> therefore, it is our opinion that academic frustration and
>>>> taunting from the other children are causing his behavior
>>>> problems. in timmy's best interests therefore, we will will be
>>>> making arrangements for him to attend happy valley retards school
>>>> where his special needs can be better accommodated. you will be
>>>> contacted directly by happy valley's admissions director, ms. u.
>>>> gottabekiddingme, ph.d., and their learning difficulties
>>>> specialist, dr. i. v. ritalin, who will be supervising his
>>>> treatments.
>>> Was this supposed to be cutting? Or amusing? Or anything other
>>> than pathetic?
>> no, it's illustrative of how retards get into psychology - they get
>> exposed to it young.
>
> You remain short of a clue jim. And obviously you have not been able to
> comprehend Gaussian distributions.
that's irrelevant! and it's called a "normal distribution" in the real
world, retard. trying to regurgitate a foreign sounding name for some
basic formula he's just dug of his old psych stats 101 notes doesn't
exactly impress. you'd know that if you actually understood any of it,
retard.
> Again, such a simple concept. I am
> starting to think that you are lying about being smarter than me.
you're a fucking joke, retard.
|
| | | | | | | | | | | | | | | | |
Date: 27 Jun 2007 18:36:13
From: Johnny Sunset
Subject: Re: High Speed Shimmy
|
On Jun 27, 7:18 pm, Bill Sornson wrote:
>
> THANK GOD ALMIGHTY! OUR LONG (ENDLESS) USENET NIGHTMARE IS (MAY BE) OVER!!!
Mikey V is hitting the trails on a MTB?
--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
|
| | | | | | | | | | | | | | | | | |
Date: 27 Jun 2007 21:40:15
From: Bill Sornson
Subject: Re: High Speed Shimmy
|
Johnny Sunset wrote:
> On Jun 27, 7:18 pm, Bill Sornson wrote:
>>
>> THANK GOD ALMIGHTY! OUR LONG (ENDLESS) USENET NIGHTMARE IS (MAY BE)
>> OVER!!!
>
> Mikey V is hitting the trails on a MTB?
OK, I have a question: why on earth would you delete the (quite brief)
content of the above? Is it a compulsion or something?
Seriously.
(If you were just going for a laugh, OK I guess I get it; however, on THIS
group, the endless back-&-forths between jim and Tim are much more known and
therefore pertinent.)
Baffled a Bit Bill
|
| | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 09:06:40
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> Tim McNamara wrote:
> >>>>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> >>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >>>>>>>
> >>>>>>>>>>>> This comes up so often at my end of the business. We had
> >>>>>>>>>>>> one person who was terrified there was something very
> >>>>>>>>>>>> wrong with her bike because she could get it to
> >>>>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
> >>>>>>>>>>>> road when there was a crosswind on a cold day. *All*
> >>>>>>>>>>>> those things had to exist for the shimmy to occur. And
> >>>>>>>>>>>> yet it was the bike at fault.
> >>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
> >>>>>>>>>>> the resonance of the frame and wheels should be
> >>>>>>>>>>> different, not coincident.
> >>>>>>>>>> A bike is not stable without a rider on it. Do you
> >>>>>>>>>> actually disagree with this?
> >>>>>>>>> in that the contact patch of the tire trails behind the
> >>>>>>>>> fork angle's intersection with the road, yes it is
> >>>>>>>>> inherently stable.
> >>>>>>>> So you could give the bike a push, without a rider on it,
> >>>>>>>> and it would go exactly how far before falling over?
> >>>>>>>>
> >>>>>>>> in that the
> >>>>>>>>> spring constants of both frame and tires give resonant
> >>>>>>>>> frequencies well above any frequency that can gain any
> >>>>>>>>> significant amplitude, yes, it is inherently stable.
> >>>>>>>>>
> >>>>>>>>>> And, if you don't, do you understand the ramifications of
> >>>>>>>>>> it?
> >>>>>>>>> you're working with incomplete information.
> >>>>>>>> What information did I leave out?
> >>>>>>> You don't have jim's apperceptive mass. He can see subtle
> >>>>>>> reasons for these phenomena that are obscure to the rest of
> >>>>>>> us mere mortals.
> >>>>>> one thing's for sure: there's a helluva lot that's obscure to
> >>>>>> retards.
> >>>>> Well, obscure to you anyway.
> >>>>>
> >>>>>>> You see, jim was a metallurgist whereas you've only been a
> >>>>>>> bike shop owner for the past 30 years or so.
> >>>>>> with all due respect to bike store owners, 30 years on the job
> >>>>>> doesn't automatically make them scientists expert in analysis
> >>>>>> of this kind of problem. just like window frame fitters
> >>>>>> turned psychologists aren't automatically good at the most
> >>>>>> basic of math concepts.
> >>>>> That's "glazier" to you. :-) Of course, by the same token
> >>>>> metallurgists aren't automatically good at mechanical
> >>>>> engineering- as the mechanical engineers have been pointing out
> >>>>> to you for years.
> >>>> funny. like it took a metallurgist to point out that the
> >>>> tensiometer math in "the book" had omitted spoke stiffness -
> >>>> that's supposed to be "mechanical engineering". but you'd
> >>>> already spotted that error hadn't you timmy - you were just
> >>>> waiting for the right time to say something.
> >>> Nope, hadn't noticed. But since the issue had already been
> >>> discussed by Jobst and others long before you turned up in the
> >>> newsgroup, I was aware of it.
> >> really, so after this so-called "discussion of which you were
> >> previously aware", you were still deceived. doesn't say much for
> >> your mental acuity. does it timmy.
> >
> > I wrote that poorly. I hadn't noticed the spoke stiffness issue
> > when I read "The Bicycle Wheel" for the first time or two. Once I
> > started participating in the newsgroup, ca. 1993, the issue was
> > under discussion somewhere around that time.
>
> and unresolved.
Correct.
> > Joe Riel and Tuns Lee made it definitive later-
>
> yes, after i raised it.
It had been raised in the past, which you overlook in your usual
self-serving manner (you should look up "self-serving bias" too). You
might have regurgitated that iteration, I don't recall. But you didn't
actually bother to be involved in coming up with the proof, suggesting
once again that it was beyond you despite your grandiose claims.
> > and, as you don't bother to note, those proofs were accepted.
>
> er, were we discussing specifics? i thought we were just discussing
> your retardation.
There it is again. When you end up on the wrong side of the argument,
you just hurl epithets. It's a sign of the weakness of your position
and the limitations of your thought processes.
> > You on the other had, can't be bothered to provide actual proof or
> > even to participate in a discussion of the advanced math involved.
>
> you know, for a retard that doesn't know enough math to tell whether
> 5000 > 1600 or 1600 < 5000, that's pretty fucking rich.
You seem to believe that if you repeat a lie long enough and strenuously
enough, it will be accepted as fact.
> where were you on the "compression spoke" thread recently? you could
> have made your usual enlightening contributions to our engineering
> horizons and explained on how it was impossible to... oh, wait, you
> didn't because you're a fucking retard and don't understand. my bad.
You're right, I made no contribution to the "compression spoke" thread.
I haven't read a single article in that thread. I figured it was just
more of your usual rants and bullshit and not really worth my time.
> > You notably disappear when those discussions happen, no doubt so
> > that you don't disclose the fact that you haven't got a clue.
>
> oh my! busted by the retard! guess i'd better quit my day job then!
Nah, busted by your own behavior, jim. From what you have said
(assuming it wasn't another lie) you already have quit your day job.
You are, by your own claim, an "ex-metallurgist."
> >>>>>>>>>> Are you suggesting that a shaking rider should have no
> >>>>>>>>>> effect on a bike's resistance to shimmy?
> >>>>>>>>> the rider should not be able to make the bike shimmy. with
> >>>>>>>>> rider load, the resonance of the frame and of the wheels
> >>>>>>>>> should not be coincident. period. many old fashioned steel
> >>>>>>>>> frames /do/ shimmy because their torsional stiffness is not
> >>>>>>>>> very high, and in the old days of undished wheels, it
> >>>>>>>>> wasn't as much of a problem, but now, with 10-speed
> >>>>>>>>> ultra-dished wheels, it's a big deal. if we can't have
> >>>>>>>>> un-dished wheels, we can have torsionally stiff frames
> >>>>>>>>> where their designer has paid attention to this stuff. no
> >>>>>>>>> excuses.
> >>>>>>>> So you believe flimsy wheels are the culprit? I used to
> >>>>>>>> think so too. But after changing out wheels (lighter wheels
> >>>>>>>> exchanged for much-beefier, stiffer versions) for a number
> >>>>>>>> of people, without cure, that didn't appear to be the
> >>>>>>>> answer. I had much better success by changing the position
> >>>>>>>> of the handlebars.
> >>>>>>>>
> >>>>>>>> That's not to say that large frames aren't far more prone to
> >>>>>>>> shimmy than smaller ones. You're absolutely correct about
> >>>>>>>> that. But that wasn't the issue for the particular case I
> >>>>>>>> referenced. I didn't include the frame size; it was 56cm,
> >>>>>>>> center-to-top.
> >>>>>>>>
> >>>>>>>> Oops, I left out one other piece of information. The person
> >>>>>>>> whose bike shimmied that I mentioned also had to take one
> >>>>>>>> hand off the bars for the shimmy to occur. So you've got *5*
> >>>>>>>> things that had to exist for her bike to shimmy- #1: Only on
> >>>>>>>> this one particular road #2: Speed had to be 38mph #3: One
> >>>>>>>> hand off the bars #4: Crosswind #5: Cold
> >>>>>>>>
> >>>>>>>> So think about what I'm saying here. If it was warm, no
> >>>>>>>> shimmy. Hands on bars, no shimmy. Any other road, including
> >>>>>>>> descents at 38mph, no shimmy. Higher or lower speed, no
> >>>>>>>> shimmy. No crosswind, no shimmy. For the sake of full
> >>>>>>>> disclosure, the only thing possibly unusual about this one
> >>>>>>>> stretch of road is that it's perfectly straight for a fairly
> >>>>>>>> good distance. I think that pretty much lays everything out
> >>>>>>>> on the table.
> >>>>>>>>
> >>>>>>>> Still think it was a problem with the bike? (And yes, we did
> >>>>>>>> try different wheels. She wouldn't consider changing her
> >>>>>>>> position on the bike, so we couldn't test for that.)
> >>>>>>> Now, Mike, you know that jim is the infallible APE (All
> >>>>>>> Purpose Expert) and that if he says the problem is that the
> >>>>>>> rear wheel is too flexible, then that's the problem. If you
> >>>>>>> replace the rear wheel with a stiffer wheel and the bike
> >>>>>>> still shimmies, jim is still right- it's reality that's
> >>>>>>> wrong.
> >>>>>> how would you know? you think i'm lying when i say that 5000
> >>>>>> > 1600, so everything is bullshit to you. retard.
> >>>>> You're lying again, jim, just like you were back in that
> >>>>> thread. You keep coming up with different numbers- obviously
> >>>>> you don't get the same answer consistently when you add 2 + 2.
> >>>>> I doubt your mathematics abilities more and more. Or perhaps
> >>>>> it's your memory.
> >>>> what, "different numbers" like 5000 > 1600 as opposed to 1600 <
> >>>> 5000? you're an irredeemable fucking retard timmy!
> >>> Better that than a liar, jim.
> >> so a liar is one who says something you're too dense to
> >> comprehend? you're a fucking retard timmy.
> >
> > No, jim, a liar is a person who doesn't tell the truth. Perhaps
> > your vaunted intelligence needs some work if you can't understand
> > these simple concepts.
>
> so why do you call me a liar then retard?
As a rebuttal that doesn't bear even a slight logical connection to what
I wrote. I call you a liar because you are one, jim. You make a claim,
it gets rebutted, then you say that wasn't what you were claiming and
it's all a Jobstian conspiracy against you.
> >>>> ***
> >>>>
> >>>> dear mrs mcnamara
> >>>>
> >>>> it is with regret that we must tell you to keep your son home
> >>>> for another week's suspension again this semester. he has been
> >>>> fighting with the other boys and is becoming increasingly
> >>>> disruptive in class. in addition, as discussed at our last
> >>>> meeting, his grades continue to be well below standard, and even
> >>>> with the remedial classes he's been attending, he has shown no
> >>>> ability to catch up.
> >>>>
> >>>> in consultation with his teachers and the school counselor
> >>>> therefore, it is our opinion that academic frustration and
> >>>> taunting from the other children are causing his behavior
> >>>> problems. in timmy's best interests therefore, we will will be
> >>>> making arrangements for him to attend happy valley retards
> >>>> school where his special needs can be better accommodated. you
> >>>> will be contacted directly by happy valley's admissions
> >>>> director, ms. u. gottabekiddingme, ph.d., and their learning
> >>>> difficulties specialist, dr. i. v. ritalin, who will be
> >>>> supervising his treatments.
> >>> Was this supposed to be cutting? Or amusing? Or anything other
> >>> than pathetic?
> >> no, it's illustrative of how retards get into psychology - they
> >> get exposed to it young.
> >
> > You remain short of a clue jim. And obviously you have not been
> > able to comprehend Gaussian distributions.
>
> that's irrelevant!
It's quite relevant, jim. I told you that you have a 0.2% (and I was
being generous) of being more intelligent that I am. If you understood
Gaussian distributions, you'd understand what that sentence means.
> and it's called a "normal distribution" in the real world, retard.
> trying to regurgitate a foreign sounding name for some basic formula
> he's just dug of his old psych stats 101 notes doesn't exactly
> impress. you'd know that if you actually understood any of it,
> retard.
That's humorous, considering the source.
> > Again, such a simple concept. I am starting to think that you are
> > lying about being smarter than me.
>
> you're a fucking joke, retard.
Better that than a liar.
|
| | | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 10:31:41
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> Tim McNamara wrote:
>>>>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>
>>>>>>>> Tim McNamara wrote:
>>>>>>>>> In article <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>>>>>
>>>>>>>>>>>>>> This comes up so often at my end of the business. We had
>>>>>>>>>>>>>> one person who was terrified there was something very
>>>>>>>>>>>>>> wrong with her bike because she could get it to
>>>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
>>>>>>>>>>>>>> road when there was a crosswind on a cold day. *All*
>>>>>>>>>>>>>> those things had to exist for the shimmy to occur. And
>>>>>>>>>>>>>> yet it was the bike at fault.
>>>>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
>>>>>>>>>>>>> the resonance of the frame and wheels should be
>>>>>>>>>>>>> different, not coincident.
>>>>>>>>>>>> A bike is not stable without a rider on it. Do you
>>>>>>>>>>>> actually disagree with this?
>>>>>>>>>>> in that the contact patch of the tire trails behind the
>>>>>>>>>>> fork angle's intersection with the road, yes it is
>>>>>>>>>>> inherently stable.
>>>>>>>>>> So you could give the bike a push, without a rider on it,
>>>>>>>>>> and it would go exactly how far before falling over?
>>>>>>>>>>
>>>>>>>>>> in that the
>>>>>>>>>>> spring constants of both frame and tires give resonant
>>>>>>>>>>> frequencies well above any frequency that can gain any
>>>>>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>>>>>
>>>>>>>>>>>> And, if you don't, do you understand the ramifications of
>>>>>>>>>>>> it?
>>>>>>>>>>> you're working with incomplete information.
>>>>>>>>>> What information did I leave out?
>>>>>>>>> You don't have jim's apperceptive mass. He can see subtle
>>>>>>>>> reasons for these phenomena that are obscure to the rest of
>>>>>>>>> us mere mortals.
>>>>>>>> one thing's for sure: there's a helluva lot that's obscure to
>>>>>>>> retards.
>>>>>>> Well, obscure to you anyway.
>>>>>>>
>>>>>>>>> You see, jim was a metallurgist whereas you've only been a
>>>>>>>>> bike shop owner for the past 30 years or so.
>>>>>>>> with all due respect to bike store owners, 30 years on the job
>>>>>>>> doesn't automatically make them scientists expert in analysis
>>>>>>>> of this kind of problem. just like window frame fitters
>>>>>>>> turned psychologists aren't automatically good at the most
>>>>>>>> basic of math concepts.
>>>>>>> That's "glazier" to you. :-) Of course, by the same token
>>>>>>> metallurgists aren't automatically good at mechanical
>>>>>>> engineering- as the mechanical engineers have been pointing out
>>>>>>> to you for years.
>>>>>> funny. like it took a metallurgist to point out that the
>>>>>> tensiometer math in "the book" had omitted spoke stiffness -
>>>>>> that's supposed to be "mechanical engineering". but you'd
>>>>>> already spotted that error hadn't you timmy - you were just
>>>>>> waiting for the right time to say something.
>>>>> Nope, hadn't noticed. But since the issue had already been
>>>>> discussed by Jobst and others long before you turned up in the
>>>>> newsgroup, I was aware of it.
>>>> really, so after this so-called "discussion of which you were
>>>> previously aware", you were still deceived. doesn't say much for
>>>> your mental acuity. does it timmy.
>>> I wrote that poorly. I hadn't noticed the spoke stiffness issue
>>> when I read "The Bicycle Wheel" for the first time or two. Once I
>>> started participating in the newsgroup, ca. 1993, the issue was
>>> under discussion somewhere around that time.
>> and unresolved.
>
> Correct.
you participated but didn't resolve? my, that was useful of you timmy.
you should have used a gaussian model.
>
>>> Joe Riel and Tuns Lee made it definitive later-
>> yes, after i raised it.
>
> It had been raised in the past, which you overlook in your usual
> self-serving manner (you should look up "self-serving bias" too). You
> might have regurgitated that iteration, I don't recall. But you didn't
> actually bother to be involved in coming up with the proof, suggesting
> once again that it was beyond you despite your grandiose claims.
the bottom line, retard, is that i care that it gets resolved. i
provoke discussion accordingly. sometime i contribute the solution,
sometime others get there first. as long as it gets resolved, the rest
is unimportant. you on the other hand just sit there, pick fights with
people that dare question the status quo and call people that say things
you don't understand, in a manner you don't like, liars. that makes you
a retard. that's not "retard" as an epithet or insult, merely statement
of fact. you don't get it. you're stupid, combative and incapable of
logic. further, you're incapable of learning - you /are/ a retard.
<snip remaining crap >
|
| | | | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 15:03:39
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <Sd6dncURo6njN-PbnZ2dnUVZ_u6rnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> Tim McNamara wrote:
> >>>>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
> >>>>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>>>
> >>>>>>>> Tim McNamara wrote:
> >>>>>>>>> In article
> >>>>>>>>> <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> >>>>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >>>>>>>>>
> >>>>>>>>>>>>>> This comes up so often at my end of the business. We
> >>>>>>>>>>>>>> had one person who was terrified there was something
> >>>>>>>>>>>>>> very wrong with her bike because she could get it to
> >>>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
> >>>>>>>>>>>>>> road when there was a crosswind on a cold day. *All*
> >>>>>>>>>>>>>> those things had to exist for the shimmy to occur. And
> >>>>>>>>>>>>>> yet it was the bike at fault.
> >>>>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
> >>>>>>>>>>>>> the resonance of the frame and wheels should be
> >>>>>>>>>>>>> different, not coincident.
> >>>>>>>>>>>> A bike is not stable without a rider on it. Do you
> >>>>>>>>>>>> actually disagree with this?
> >>>>>>>>>>> in that the contact patch of the tire trails behind the
> >>>>>>>>>>> fork angle's intersection with the road, yes it is
> >>>>>>>>>>> inherently stable.
> >>>>>>>>>> So you could give the bike a push, without a rider on it,
> >>>>>>>>>> and it would go exactly how far before falling over?
> >>>>>>>>>>
> >>>>>>>>>> in that the
> >>>>>>>>>>> spring constants of both frame and tires give resonant
> >>>>>>>>>>> frequencies well above any frequency that can gain any
> >>>>>>>>>>> significant amplitude, yes, it is inherently stable.
> >>>>>>>>>>>
> >>>>>>>>>>>> And, if you don't, do you understand the ramifications
> >>>>>>>>>>>> of it?
> >>>>>>>>>>> you're working with incomplete information.
> >>>>>>>>>> What information did I leave out?
> >>>>>>>>> You don't have jim's apperceptive mass. He can see subtle
> >>>>>>>>> reasons for these phenomena that are obscure to the rest of
> >>>>>>>>> us mere mortals.
> >>>>>>>> one thing's for sure: there's a helluva lot that's obscure
> >>>>>>>> to retards.
> >>>>>>> Well, obscure to you anyway.
> >>>>>>>
> >>>>>>>>> You see, jim was a metallurgist whereas you've only been a
> >>>>>>>>> bike shop owner for the past 30 years or so.
> >>>>>>>> with all due respect to bike store owners, 30 years on the
> >>>>>>>> job doesn't automatically make them scientists expert in
> >>>>>>>> analysis of this kind of problem. just like window frame
> >>>>>>>> fitters turned psychologists aren't automatically good at
> >>>>>>>> the most basic of math concepts.
> >>>>>>> That's "glazier" to you. :-) Of course, by the same token
> >>>>>>> metallurgists aren't automatically good at mechanical
> >>>>>>> engineering- as the mechanical engineers have been pointing
> >>>>>>> out to you for years.
> >>>>>> funny. like it took a metallurgist to point out that the
> >>>>>> tensiometer math in "the book" had omitted spoke stiffness -
> >>>>>> that's supposed to be "mechanical engineering". but you'd
> >>>>>> already spotted that error hadn't you timmy - you were just
> >>>>>> waiting for the right time to say something.
> >>>>> Nope, hadn't noticed. But since the issue had already been
> >>>>> discussed by Jobst and others long before you turned up in the
> >>>>> newsgroup, I was aware of it.
> >>>> really, so after this so-called "discussion of which you were
> >>>> previously aware", you were still deceived. doesn't say much
> >>>> for your mental acuity. does it timmy.
> >>> I wrote that poorly. I hadn't noticed the spoke stiffness issue
> >>> when I read "The Bicycle Wheel" for the first time or two. Once
> >>> I started participating in the newsgroup, ca. 1993, the issue was
> >>> under discussion somewhere around that time.
> >> and unresolved.
> >
> > Correct.
>
> you participated but didn't resolve? my, that was useful of you
> timmy. you should have used a gaussian model.
At that time I didn't adequately understand the issues to resolve the
issue.
> >>> Joe Riel and Tuns Lee made it definitive later-
> >> yes, after i raised it.
> >
> > It had been raised in the past, which you overlook in your usual
> > self-serving manner (you should look up "self-serving bias" too).
> > You might have regurgitated that iteration, I don't recall. But
> > you didn't actually bother to be involved in coming up with the
> > proof, suggesting once again that it was beyond you despite your
> > grandiose claims.
>
> the bottom line, retard, is that i care that it gets resolved. i
> provoke discussion accordingly. sometime i contribute the solution,
> sometime others get there first. as long as it gets resolved, the
> rest is unimportant.
That's another lie, jim. It's clear from reading hundreds of your posts
that what you care about is discrediting Jobst and, by extension, anyone
who agrees with him on any topic.
> you on the other hand just sit there, pick fights with people that
> dare question the status quo and call people that say things you
> don't understand, in a manner you don't like, liars. that makes you
> a retard. that's not "retard" as an epithet or insult, merely
> statement of fact. you don't get it. you're stupid, combative and
> incapable of logic. further, you're incapable of learning - you
> /are/ a retard.
Once again you display your infacility with concepts and meaning. Oh
well.
> <snip remaining crap>
If you snipped all the crap, jim, you'd stop posting.
|
| | | | | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 13:20:00
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <Sd6dncURo6njN-PbnZ2dnUVZ_u6rnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> Tim McNamara wrote:
>>>>>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>
>>>>>>>> Tim McNamara wrote:
>>>>>>>>> In article <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>>>
>>>>>>>>>> Tim McNamara wrote:
>>>>>>>>>>> In article
>>>>>>>>>>> <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>>>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>>>>>>> This comes up so often at my end of the business. We
>>>>>>>>>>>>>>>> had one person who was terrified there was something
>>>>>>>>>>>>>>>> very wrong with her bike because she could get it to
>>>>>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one particular
>>>>>>>>>>>>>>>> road when there was a crosswind on a cold day. *All*
>>>>>>>>>>>>>>>> those things had to exist for the shimmy to occur. And
>>>>>>>>>>>>>>>> yet it was the bike at fault.
>>>>>>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
>>>>>>>>>>>>>>> the resonance of the frame and wheels should be
>>>>>>>>>>>>>>> different, not coincident.
>>>>>>>>>>>>>> A bike is not stable without a rider on it. Do you
>>>>>>>>>>>>>> actually disagree with this?
>>>>>>>>>>>>> in that the contact patch of the tire trails behind the
>>>>>>>>>>>>> fork angle's intersection with the road, yes it is
>>>>>>>>>>>>> inherently stable.
>>>>>>>>>>>> So you could give the bike a push, without a rider on it,
>>>>>>>>>>>> and it would go exactly how far before falling over?
>>>>>>>>>>>>
>>>>>>>>>>>> in that the
>>>>>>>>>>>>> spring constants of both frame and tires give resonant
>>>>>>>>>>>>> frequencies well above any frequency that can gain any
>>>>>>>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>>>>>>>
>>>>>>>>>>>>>> And, if you don't, do you understand the ramifications
>>>>>>>>>>>>>> of it?
>>>>>>>>>>>>> you're working with incomplete information.
>>>>>>>>>>>> What information did I leave out?
>>>>>>>>>>> You don't have jim's apperceptive mass. He can see subtle
>>>>>>>>>>> reasons for these phenomena that are obscure to the rest of
>>>>>>>>>>> us mere mortals.
>>>>>>>>>> one thing's for sure: there's a helluva lot that's obscure
>>>>>>>>>> to retards.
>>>>>>>>> Well, obscure to you anyway.
>>>>>>>>>
>>>>>>>>>>> You see, jim was a metallurgist whereas you've only been a
>>>>>>>>>>> bike shop owner for the past 30 years or so.
>>>>>>>>>> with all due respect to bike store owners, 30 years on the
>>>>>>>>>> job doesn't automatically make them scientists expert in
>>>>>>>>>> analysis of this kind of problem. just like window frame
>>>>>>>>>> fitters turned psychologists aren't automatically good at
>>>>>>>>>> the most basic of math concepts.
>>>>>>>>> That's "glazier" to you. :-) Of course, by the same token
>>>>>>>>> metallurgists aren't automatically good at mechanical
>>>>>>>>> engineering- as the mechanical engineers have been pointing
>>>>>>>>> out to you for years.
>>>>>>>> funny. like it took a metallurgist to point out that the
>>>>>>>> tensiometer math in "the book" had omitted spoke stiffness -
>>>>>>>> that's supposed to be "mechanical engineering". but you'd
>>>>>>>> already spotted that error hadn't you timmy - you were just
>>>>>>>> waiting for the right time to say something.
>>>>>>> Nope, hadn't noticed. But since the issue had already been
>>>>>>> discussed by Jobst and others long before you turned up in the
>>>>>>> newsgroup, I was aware of it.
>>>>>> really, so after this so-called "discussion of which you were
>>>>>> previously aware", you were still deceived. doesn't say much
>>>>>> for your mental acuity. does it timmy.
>>>>> I wrote that poorly. I hadn't noticed the spoke stiffness issue
>>>>> when I read "The Bicycle Wheel" for the first time or two. Once
>>>>> I started participating in the newsgroup, ca. 1993, the issue was
>>>>> under discussion somewhere around that time.
>>>> and unresolved.
>>> Correct.
>> you participated but didn't resolve? my, that was useful of you
>> timmy. you should have used a gaussian model.
>
> At that time I didn't adequately understand the issues to resolve the
> issue.
>
>>>>> Joe Riel and Tuns Lee made it definitive later-
>>>> yes, after i raised it.
>>> It had been raised in the past, which you overlook in your usual
>>> self-serving manner (you should look up "self-serving bias" too).
>>> You might have regurgitated that iteration, I don't recall. But
>>> you didn't actually bother to be involved in coming up with the
>>> proof, suggesting once again that it was beyond you despite your
>>> grandiose claims.
>> the bottom line, retard, is that i care that it gets resolved. i
>> provoke discussion accordingly. sometime i contribute the solution,
>> sometime others get there first. as long as it gets resolved, the
>> rest is unimportant.
>
> That's another lie, jim. It's clear from reading hundreds of your posts
> that what you care about is discrediting Jobst and, by extension, anyone
> who agrees with him on any topic.
when someone parrots a jobstian untruth, like anodizing "causes" rim
cracking for example, i'm going to take issue with them for repeating
b.s. buy you don't understand the distinction because you're too
fucking retarded.
and i'm not out to "discredit" jobst. i simply want him to correct the
errors that cost the industry millions of dollars and set would-be
engineers down the wrong road of misunderstanding the principles. but
you wouldn't understand the distinction because you're too fucking retarded.
>
>> you on the other hand just sit there, pick fights with people that
>> dare question the status quo and call people that say things you
>> don't understand, in a manner you don't like, liars. that makes you
>> a retard. that's not "retard" as an epithet or insult, merely
>> statement of fact. you don't get it. you're stupid, combative and
>> incapable of logic. further, you're incapable of learning - you
>> /are/ a retard.
>
> Once again you display your infacility with concepts and meaning.
eh? from a guy that doesn't get basic math, that's retarded.
> Oh
> well.
>
>> <snip remaining crap>
>
> If you snipped all the crap, jim, you'd stop posting.
if you weren't retarded, you'd understand what the fuck you were talking
about and get to the fucking point. instead, you just want to fucking
argue. well, if that's what it take, i'll oblige your dumb ass. but
you're still a fucking retard.
|
| | | | | | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 20:24:38
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <i_KdnfKLO9ZsTOPbnZ2dnUVZ_v2knZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <Sd6dncURo6njN-PbnZ2dnUVZ_u6rnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> Tim McNamara wrote:
> >>>>>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
> >>>>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>>>
> >>>>>>>> Tim McNamara wrote:
> >>>>>>>>> In article
> >>>>>>>>> <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
> >>>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>>>>>
> >>>>>>>>>> Tim McNamara wrote:
> >>>>>>>>>>> In article
> >>>>>>>>>>> <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
> >>>>>>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >>>>>>>>>>>
> >>>>>>>>>>>>>>>> This comes up so often at my end of the business. We
> >>>>>>>>>>>>>>>> had one person who was terrified there was something
> >>>>>>>>>>>>>>>> very wrong with her bike because she could get it to
> >>>>>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one
> >>>>>>>>>>>>>>>> particular road when there was a crosswind on a cold
> >>>>>>>>>>>>>>>> day. *All* those things had to exist for the shimmy
> >>>>>>>>>>>>>>>> to occur. And yet it was the bike at fault.
> >>>>>>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
> >>>>>>>>>>>>>>> the resonance of the frame and wheels should be
> >>>>>>>>>>>>>>> different, not coincident.
> >>>>>>>>>>>>>> A bike is not stable without a rider on it. Do you
> >>>>>>>>>>>>>> actually disagree with this?
> >>>>>>>>>>>>> in that the contact patch of the tire trails behind the
> >>>>>>>>>>>>> fork angle's intersection with the road, yes it is
> >>>>>>>>>>>>> inherently stable.
> >>>>>>>>>>>> So you could give the bike a push, without a rider on
> >>>>>>>>>>>> it, and it would go exactly how far before falling over?
> >>>>>>>>>>>>
> >>>>>>>>>>>> in that the
> >>>>>>>>>>>>> spring constants of both frame and tires give resonant
> >>>>>>>>>>>>> frequencies well above any frequency that can gain any
> >>>>>>>>>>>>> significant amplitude, yes, it is inherently stable.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> And, if you don't, do you understand the ramifications
> >>>>>>>>>>>>>> of it?
> >>>>>>>>>>>>> you're working with incomplete information.
> >>>>>>>>>>>> What information did I leave out?
> >>>>>>>>>>> You don't have jim's apperceptive mass. He can see
> >>>>>>>>>>> subtle reasons for these phenomena that are obscure to
> >>>>>>>>>>> the rest of us mere mortals.
> >>>>>>>>>> one thing's for sure: there's a helluva lot that's obscure
> >>>>>>>>>> to retards.
> >>>>>>>>> Well, obscure to you anyway.
> >>>>>>>>>
> >>>>>>>>>>> You see, jim was a metallurgist whereas you've only been
> >>>>>>>>>>> a bike shop owner for the past 30 years or so.
> >>>>>>>>>> with all due respect to bike store owners, 30 years on the
> >>>>>>>>>> job doesn't automatically make them scientists expert in
> >>>>>>>>>> analysis of this kind of problem. just like window frame
> >>>>>>>>>> fitters turned psychologists aren't automatically good at
> >>>>>>>>>> the most basic of math concepts.
> >>>>>>>>> That's "glazier" to you. :-) Of course, by the same token
> >>>>>>>>> metallurgists aren't automatically good at mechanical
> >>>>>>>>> engineering- as the mechanical engineers have been pointing
> >>>>>>>>> out to you for years.
> >>>>>>>> funny. like it took a metallurgist to point out that the
> >>>>>>>> tensiometer math in "the book" had omitted spoke stiffness -
> >>>>>>>> that's supposed to be "mechanical engineering". but you'd
> >>>>>>>> already spotted that error hadn't you timmy - you were just
> >>>>>>>> waiting for the right time to say something.
> >>>>>>> Nope, hadn't noticed. But since the issue had already been
> >>>>>>> discussed by Jobst and others long before you turned up in
> >>>>>>> the newsgroup, I was aware of it.
> >>>>>> really, so after this so-called "discussion of which you were
> >>>>>> previously aware", you were still deceived. doesn't say much
> >>>>>> for your mental acuity. does it timmy.
> >>>>> I wrote that poorly. I hadn't noticed the spoke stiffness
> >>>>> issue when I read "The Bicycle Wheel" for the first time or
> >>>>> two. Once I started participating in the newsgroup, ca. 1993,
> >>>>> the issue was under discussion somewhere around that time.
> >>>> and unresolved.
> >>> Correct.
> >> you participated but didn't resolve? my, that was useful of you
> >> timmy. you should have used a gaussian model.
> >
> > At that time I didn't adequately understand the issues to resolve
> > the issue.
> >
> >>>>> Joe Riel and Tuns Lee made it definitive later-
> >>>> yes, after i raised it.
> >>> It had been raised in the past, which you overlook in your usual
> >>> self-serving manner (you should look up "self-serving bias" too).
> >>> You might have regurgitated that iteration, I don't recall. But
> >>> you didn't actually bother to be involved in coming up with the
> >>> proof, suggesting once again that it was beyond you despite your
> >>> grandiose claims.
> >> the bottom line, retard, is that i care that it gets resolved. i
> >> provoke discussion accordingly. sometime i contribute the
> >> solution, sometime others get there first. as long as it gets
> >> resolved, the rest is unimportant.
> >
> > That's another lie, jim. It's clear from reading hundreds of your
> > posts that what you care about is discrediting Jobst and, by
> > extension, anyone who agrees with him on any topic.
>
> when someone parrots a jobstian untruth, like anodizing "causes" rim
> cracking for example, i'm going to take issue with them for repeating
> b.s. buy you don't understand the distinction because you're too
> fucking retarded.
Sorry jim, the metals industry (including current metallurgists)
disagrees with you. You've been provided with abundant citations about
anodizing from within the industry, people who are employed in the field
you also claim. My experience with anodized and non-anodized rims-
being able to control the variables other than the rim- also makes it
quite clear to me that your objection is baseless. Anodized rims are
much more prone to failure by cracking around the spoke holes than
non-anodized rims.
And of course, once you are disproved on this you cast about for other
things to blame on Jobst such as "rim tension as high as the rim can
bear." A little while later, you think that we have forgotten that the
metals fabrication industry contradicts your specious claims that
anodizing doesn't lead to failure and you trot them out again.
You must work for Mavic USA given how hard you shill for them in this
newsgroup.
> and i'm not out to "discredit" jobst. i simply want him to correct
> the errors that cost the industry millions of dollars and set
> would-be engineers down the wrong road of misunderstanding the
> principles. but you wouldn't understand the distinction because
> you're too fucking retarded.
The distinction is simple, what's lacking is the evidence that you're
right and he's wrong.
> >> you on the other hand just sit there, pick fights with people that
> >> dare question the status quo and call people that say things you
> >> don't understand, in a manner you don't like, liars. that makes
> >> you a retard. that's not "retard" as an epithet or insult, merely
> >> statement of fact. you don't get it. you're stupid, combative
> >> and incapable of logic. further, you're incapable of learning -
> >> you /are/ a retard.
> >
> > Once again you display your infacility with concepts and meaning.
>
> eh? from a guy that doesn't get basic math, that's retarded.
Pull the other one, it's got bells on it.
> > Oh well.
> >
> >> <snip remaining crap>
> >
> > If you snipped all the crap, jim, you'd stop posting.
>
> if you weren't retarded, you'd understand what the fuck you were
> talking about and get to the fucking point. instead, you just want
> to fucking argue. well, if that's what it take, i'll oblige your
> dumb ass. but you're still a fucking retard.
Really, jim, do you think that this puerile ranting puts you in a good
light or puts me in a bad light? If so, I am not the one who's
cognitively challenged.
|
| | | | | | | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 21:33:10
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <i_KdnfKLO9ZsTOPbnZ2dnUVZ_v2knZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <Sd6dncURo6njN-PbnZ2dnUVZ_u6rnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <wfednfhujdLcmOPbnZ2dnUVZ_t-mnZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> Tim McNamara wrote:
>>>>>>> In article <1MydnfBVv4LCJ-DbnZ2dnUVZ_gadnZ2d@speakeasy.net>,
>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>
>>>>>>>> Tim McNamara wrote:
>>>>>>>>> In article <iOidnSsdFcFZg-DbnZ2dnUVZ_oytnZ2d@speakeasy.net>,
>>>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>>>
>>>>>>>>>> Tim McNamara wrote:
>>>>>>>>>>> In article
>>>>>>>>>>> <sN2dndebCZKWHOHbnZ2dnUVZ_sudnZ2d@speakeasy.net>,
>>>>>>>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Tim McNamara wrote:
>>>>>>>>>>>>> In article
>>>>>>>>>>>>> <l2Jei.17444$y_7.7883@newssvr27.news.prodigy.net>,
>>>>>>>>>>>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> This comes up so often at my end of the business. We
>>>>>>>>>>>>>>>>>> had one person who was terrified there was something
>>>>>>>>>>>>>>>>>> very wrong with her bike because she could get it to
>>>>>>>>>>>>>>>>>> shimmy/wobble at 38 mph descending this one
>>>>>>>>>>>>>>>>>> particular road when there was a crosswind on a cold
>>>>>>>>>>>>>>>>>> day. *All* those things had to exist for the shimmy
>>>>>>>>>>>>>>>>>> to occur. And yet it was the bike at fault.
>>>>>>>>>>>>>>>>> it is. bike shouldn't do it under any circumstances.
>>>>>>>>>>>>>>>>> the resonance of the frame and wheels should be
>>>>>>>>>>>>>>>>> different, not coincident.
>>>>>>>>>>>>>>>> A bike is not stable without a rider on it. Do you
>>>>>>>>>>>>>>>> actually disagree with this?
>>>>>>>>>>>>>>> in that the contact patch of the tire trails behind the
>>>>>>>>>>>>>>> fork angle's intersection with the road, yes it is
>>>>>>>>>>>>>>> inherently stable.
>>>>>>>>>>>>>> So you could give the bike a push, without a rider on
>>>>>>>>>>>>>> it, and it would go exactly how far before falling over?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> in that the
>>>>>>>>>>>>>>> spring constants of both frame and tires give resonant
>>>>>>>>>>>>>>> frequencies well above any frequency that can gain any
>>>>>>>>>>>>>>> significant amplitude, yes, it is inherently stable.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> And, if you don't, do you understand the ramifications
>>>>>>>>>>>>>>>> of it?
>>>>>>>>>>>>>>> you're working with incomplete information.
>>>>>>>>>>>>>> What information did I leave out?
>>>>>>>>>>>>> You don't have jim's apperceptive mass. He can see
>>>>>>>>>>>>> subtle reasons for these phenomena that are obscure to
>>>>>>>>>>>>> the rest of us mere mortals.
>>>>>>>>>>>> one thing's for sure: there's a helluva lot that's obscure
>>>>>>>>>>>> to retards.
>>>>>>>>>>> Well, obscure to you anyway.
>>>>>>>>>>>
>>>>>>>>>>>>> You see, jim was a metallurgist whereas you've only been
>>>>>>>>>>>>> a bike shop owner for the past 30 years or so.
>>>>>>>>>>>> with all due respect to bike store owners, 30 years on the
>>>>>>>>>>>> job doesn't automatically make them scientists expert in
>>>>>>>>>>>> analysis of this kind of problem. just like window frame
>>>>>>>>>>>> fitters turned psychologists aren't automatically good at
>>>>>>>>>>>> the most basic of math concepts.
>>>>>>>>>>> That's "glazier" to you. :-) Of course, by the same token
>>>>>>>>>>> metallurgists aren't automatically good at mechanical
>>>>>>>>>>> engineering- as the mechanical engineers have been pointing
>>>>>>>>>>> out to you for years.
>>>>>>>>>> funny. like it took a metallurgist to point out that the
>>>>>>>>>> tensiometer math in "the book" had omitted spoke stiffness -
>>>>>>>>>> that's supposed to be "mechanical engineering". but you'd
>>>>>>>>>> already spotted that error hadn't you timmy - you were just
>>>>>>>>>> waiting for the right time to say something.
>>>>>>>>> Nope, hadn't noticed. But since the issue had already been
>>>>>>>>> discussed by Jobst and others long before you turned up in
>>>>>>>>> the newsgroup, I was aware of it.
>>>>>>>> really, so after this so-called "discussion of which you were
>>>>>>>> previously aware", you were still deceived. doesn't say much
>>>>>>>> for your mental acuity. does it timmy.
>>>>>>> I wrote that poorly. I hadn't noticed the spoke stiffness
>>>>>>> issue when I read "The Bicycle Wheel" for the first time or
>>>>>>> two. Once I started participating in the newsgroup, ca. 1993,
>>>>>>> the issue was under discussion somewhere around that time.
>>>>>> and unresolved.
>>>>> Correct.
>>>> you participated but didn't resolve? my, that was useful of you
>>>> timmy. you should have used a gaussian model.
>>> At that time I didn't adequately understand the issues to resolve
>>> the issue.
>>>
>>>>>>> Joe Riel and Tuns Lee made it definitive later-
>>>>>> yes, after i raised it.
>>>>> It had been raised in the past, which you overlook in your usual
>>>>> self-serving manner (you should look up "self-serving bias" too).
>>>>> You might have regurgitated that iteration, I don't recall. But
>>>>> you didn't actually bother to be involved in coming up with the
>>>>> proof, suggesting once again that it was beyond you despite your
>>>>> grandiose claims.
>>>> the bottom line, retard, is that i care that it gets resolved. i
>>>> provoke discussion accordingly. sometime i contribute the
>>>> solution, sometime others get there first. as long as it gets
>>>> resolved, the rest is unimportant.
>>> That's another lie, jim. It's clear from reading hundreds of your
>>> posts that what you care about is discrediting Jobst and, by
>>> extension, anyone who agrees with him on any topic.
>> when someone parrots a jobstian untruth, like anodizing "causes" rim
>> cracking for example, i'm going to take issue with them for repeating
>> b.s. buy you don't understand the distinction because you're too
>> fucking retarded.
>
> Sorry jim, the metals industry (including current metallurgists)
> disagrees with you. You've been provided with abundant citations about
> anodizing from within the industry, people who are employed in the field
> you also claim.
sorry timmy, you just don't read. [surprise!]
as i've written many times - anodizing /can/ indeed cause cracking, but
it's not OBSERVED to be the initiator in this instance. [and a dye
penetrant test, the "analysis" cited by jobst, simply cannot reveal
cause, only progress.] in reality, the dominant failure mode is stress
cracking along the extrusion axis, as you would expect with any highly
anisotropic material loaded perpendicular to elongation. [and jobst
didn't know about anisotropy when he concocted his theory.]
> My experience with anodized and non-anodized rims-
> being able to control the variables other than the rim- also makes it
> quite clear to me that your objection is baseless.
but you don't have experience with non-anodized rims - your ma2's are
green label, not red. that means they're _all_ anodized. just like the
aluminum window frames with which which you purported to be so familiar,
but were so similarly and shamefully confused.
> Anodized rims are
> much more prone to failure by cracking around the spoke holes than
> non-anodized rims.
not provably. anodizing coincided with spoke tension "as high as the
rim can bear". that'll crack any rim, even ma2's. as cited here many
times.
>
> And of course, once you are disproved on this you cast about for other
> things to blame on Jobst such as "rim tension as high as the rim can
> bear." A little while later, you think that we have forgotten that the
> metals fabrication industry contradicts your specious claims that
> anodizing doesn't lead to failure and you trot them out again.
you are /so/ retarded - you're taking jobst's mistake and rolling it
into your own misunderstanding. [this is /the/ reason why i take such
issue with jobst's errors - it pollutes a whole generation's knowledge
pool.]
remember this thread?
http://groups.google.com/group/rec.bicycles.tech/browse_thread/thread/6833b89438e063b8/8c3d1cdca62d0d49?lnk=gst&q=question+of+principle&rnum=1#8c3d1cdca62d0d49
you notably didn't respond - presumably because you didn't understand.
and if you can't grasp basic principles, you never will.
>
> You must work for Mavic USA given how hard you shill for them in this
> newsgroup.
i've said many times that i don't. cognitive dissonance and failing
recall. hmmm. aren't they symptoms of something timmy? er, this is a
hard one... got it! retardation! timmy, you're a retard!
>
>> and i'm not out to "discredit" jobst. i simply want him to correct
>> the errors that cost the industry millions of dollars and set
>> would-be engineers down the wrong road of misunderstanding the
>> principles. but you wouldn't understand the distinction because
>> you're too fucking retarded.
>
> The distinction is simple, what's lacking is the evidence that you're
> right and he's wrong.
you think that simply because you're too retarded to understand.
http://www.theflatearthsociety.org/
the earth is flat, right? any fool, sorry, retard, can /see/ it's flat!
>
>>>> you on the other hand just sit there, pick fights with people that
>>>> dare question the status quo and call people that say things you
>>>> don't understand, in a manner you don't like, liars. that makes
>>>> you a retard. that's not "retard" as an epithet or insult, merely
>>>> statement of fact. you don't get it. you're stupid, combative
>>>> and incapable of logic. further, you're incapable of learning -
>>>> you /are/ a retard.
>>> Once again you display your infacility with concepts and meaning.
>> eh? from a guy that doesn't get basic math, that's retarded.
>
> Pull the other one, it's got bells on it.
ok, since you say you know what you're doing, let's pick a very simple
[and recent] example:
"rear wheel spoke tension ratio differential. discuss."
you can't crib from jobst on this one timmy - he's not addressed it.
and no, there is not a gaussian solution.
>
>> > Oh well.
>>>> <snip remaining crap>
>>> If you snipped all the crap, jim, you'd stop posting.
>> if you weren't retarded, you'd understand what the fuck you were
>> talking about and get to the fucking point. instead, you just want
>> to fucking argue. well, if that's what it take, i'll oblige your
>> dumb ass. but you're still a fucking retard.
>
> Really, jim, do you think that this puerile ranting puts you in a good
> light or puts me in a bad light? If so, I am not the one who's
> cognitively challenged.
so why do you rise to the bait so obligingly? [that's a rhetorical
answer timmy - you're not supposed to answer.] i can be as dumb as i
want - i'm the anonymous troll, remember? [rhetorical] you otoh want
to make out like you're smart enough to tell me i'm wrong, but instead
make fuck-ups by citing bullshit like gaussian distributions out of
context. all you therefore achieve is letting a troll taunt you into
revealing how retarded you are!!! [that must really take dedication and
cranial rock implantation. tell me, did the surgery hurt? [rhetorical]]
anyway, timmy boy, i'm off for a summer vacation soon. that means i may
not be able to taunt you full time for a week or two. use the time
constructively won't you? [rhetorical] but i'll check in when i can.
vacation is about having fun, and i do /so/ love having your dumb ass
bounce each time i kick it - i'll miss you. much better than video games.
bye bye retard!
|
| | | | | | | | | | | | | | | | | | | | | | |
Date: 25 Jun 2007 21:55:42
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
> anyway, timmy boy, i'm off for a summer vacation soon. that means i
> may not be able to taunt you full time for a week or two. use the
> time constructively won't you? [rhetorical] but i'll check in when
> i can. vacation is about having fun, and i do /so/ love having your
> dumb ass bounce each time i kick it - i'll miss you. much better
> than video games.
>
> bye bye retard!
Have a great vacation, jim.
|
| | | | | | | | | | | | | | | | | | | | | | | |
Date: 25 Jun 2007 22:23:13
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
>> anyway, timmy boy, i'm off for a summer vacation soon. that means i
>> may not be able to taunt you full time for a week or two. use the
>> time constructively won't you? [rhetorical] but i'll check in when
>> i can. vacation is about having fun, and i do /so/ love having your
>> dumb ass bounce each time i kick it - i'll miss you. much better
>> than video games.
>>
>> bye bye retard!
>
> Have a great vacation, jim.
/my/ vacation doesn't mean /you/ get one, retard. i'll still be
checking on you - just not as often.
and quit playing to the peanut gallery with this brown-nosery. you're
still a retard, just one with less self respect.
|
| | | | | | | | | | | | | | | | | | | | | | | | |
Date: 26 Jun 2007 08:57:42
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> >> anyway, timmy boy, i'm off for a summer vacation soon. that means
> >> i may not be able to taunt you full time for a week or two. use
> >> the time constructively won't you? [rhetorical] but i'll check
> >> in when i can. vacation is about having fun, and i do /so/ love
> >> having your dumb ass bounce each time i kick it - i'll miss you.
> >> much better than video games.
> >>
> >> bye bye retard!
> >
> > Have a great vacation, jim.
>
> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
> checking on you - just not as often.
Your weird stalking behavior seems to be generalizing.
> and quit playing to the peanut gallery with this brown-nosery.
> you're still a retard, just one with less self respect.
You still don't get it, jim. Anyway, have a great vacation.
|
| | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 26 Jun 2007 20:42:21
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>>> anyway, timmy boy, i'm off for a summer vacation soon. that means
>>>> i may not be able to taunt you full time for a week or two. use
>>>> the time constructively won't you? [rhetorical] but i'll check
>>>> in when i can. vacation is about having fun, and i do /so/ love
>>>> having your dumb ass bounce each time i kick it - i'll miss you.
>>>> much better than video games.
>>>>
>>>> bye bye retard!
>>> Have a great vacation, jim.
>> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
>> checking on you - just not as often.
>
> Your weird stalking behavior seems to be generalizing.
"generalizing"??? is that like generalized retardation?
>
>> and quit playing to the peanut gallery with this brown-nosery.
>> you're still a retard, just one with less self respect.
>
> You still don't get it, jim.
do i understand the apparent need to brown nose someone you've been
calling a liar? short of retardation, no i don't.
> Anyway, have a great vacation.
i will. but you can fuck off. retard.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 26 Jun 2007 23:05:02
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <TeSdndPX6_4AQRzbnZ2dnUVZ_g2dnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>>> anyway, timmy boy, i'm off for a summer vacation soon. that
> >>>> means i may not be able to taunt you full time for a week or
> >>>> two. use the time constructively won't you? [rhetorical] but
> >>>> i'll check in when i can. vacation is about having fun, and i do
> >>>> /so/ love having your dumb ass bounce each time i kick it - i'll
> >>>> miss you. much better than video games.
> >>>>
> >>>> bye bye retard!
> >>> Have a great vacation, jim.
> >> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
> >> checking on you - just not as often.
> >
> > Your weird stalking behavior seems to be generalizing.
>
> "generalizing"??? is that like generalized retardation?
Generalizing in that you are expanding from stalking Jobst to stalking
me as well.
> >> and quit playing to the peanut gallery with this brown-nosery.
> >> you're still a retard, just one with less self respect.
> >
> > You still don't get it, jim.
>
> do i understand the apparent need to brown nose someone you've been
> calling a liar? short of retardation, no i don't.
Clearly you don't.
> > Anyway, have a great vacation.
>
> i will. but you can fuck off. retard.
Some people are too screwed up to even allow civility.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 26 Jun 2007 21:31:31
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <TeSdndPX6_4AQRzbnZ2dnUVZ_g2dnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>>> anyway, timmy boy, i'm off for a summer vacation soon. that
>>>>>> means i may not be able to taunt you full time for a week or
>>>>>> two. use the time constructively won't you? [rhetorical] but
>>>>>> i'll check in when i can. vacation is about having fun, and i do
>>>>>> /so/ love having your dumb ass bounce each time i kick it - i'll
>>>>>> miss you. much better than video games.
>>>>>>
>>>>>> bye bye retard!
>>>>> Have a great vacation, jim.
>>>> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
>>>> checking on you - just not as often.
>>> Your weird stalking behavior seems to be generalizing.
>> "generalizing"??? is that like generalized retardation?
>
> Generalizing in that you are expanding from stalking Jobst to stalking
> me as well.
>
>>>> and quit playing to the peanut gallery with this brown-nosery.
>>>> you're still a retard, just one with less self respect.
>>> You still don't get it, jim.
>> do i understand the apparent need to brown nose someone you've been
>> calling a liar? short of retardation, no i don't.
>
> Clearly you don't.
>
>>> Anyway, have a great vacation.
>> i will. but you can fuck off. retard.
>
> Some people are too screwed up to even allow civility.
calling someone a liar because you're too fucking retarded to understand
what they say is hardly civil. and quit all this "but i'm just trying
to be reasonable" bullshit masquerade. you're too fucking retarded to
pull it off.
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 27 Jun 2007 08:45:27
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <cc-dnQRhDMW5dRzbnZ2dnUVZ_gqdnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <TeSdndPX6_4AQRzbnZ2dnUVZ_g2dnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>>> anyway, timmy boy, i'm off for a summer vacation soon. that
> >>>>>> means i may not be able to taunt you full time for a week or
> >>>>>> two. use the time constructively won't you? [rhetorical] but
> >>>>>> i'll check in when i can. vacation is about having fun, and i do
> >>>>>> /so/ love having your dumb ass bounce each time i kick it - i'll
> >>>>>> miss you. much better than video games.
> >>>>>>
> >>>>>> bye bye retard!
> >>>>> Have a great vacation, jim.
> >>>> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
> >>>> checking on you - just not as often.
> >>> Your weird stalking behavior seems to be generalizing.
> >> "generalizing"??? is that like generalized retardation?
> >
> > Generalizing in that you are expanding from stalking Jobst to stalking
> > me as well.
> >
> >>>> and quit playing to the peanut gallery with this brown-nosery.
> >>>> you're still a retard, just one with less self respect.
> >>> You still don't get it, jim.
> >> do i understand the apparent need to brown nose someone you've been
> >> calling a liar? short of retardation, no i don't.
> >
> > Clearly you don't.
> >
> >>> Anyway, have a great vacation.
> >> i will. but you can fuck off. retard.
> >
> > Some people are too screwed up to even allow civility.
>
> calling someone a liar because you're too fucking retarded to understand
> what they say is hardly civil. and quit all this "but i'm just trying
> to be reasonable" bullshit masquerade. you're too fucking retarded to
> pull it off.
I am reasonable, jim, which is what you don't understand.
Enjoy your vacation. I'll be enjoying mine, the annual 4th of July
college reunion party that we've been having since 1983. Hanging out
with old friends is such a treat!
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 27 Jun 2007 07:08:53
From: jim beam
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> In article <cc-dnQRhDMW5dRzbnZ2dnUVZ_gqdnZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
>> Tim McNamara wrote:
>>> In article <TeSdndPX6_4AQRzbnZ2dnUVZ_g2dnZ2d@speakeasy.net>,
>>> jim beam <spamvortex@bad.example.net> wrote:
>>>
>>>> Tim McNamara wrote:
>>>>> In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net>,
>>>>> jim beam <spamvortex@bad.example.net> wrote:
>>>>>
>>>>>> Tim McNamara wrote:
>>>>>>>> anyway, timmy boy, i'm off for a summer vacation soon. that
>>>>>>>> means i may not be able to taunt you full time for a week or
>>>>>>>> two. use the time constructively won't you? [rhetorical] but
>>>>>>>> i'll check in when i can. vacation is about having fun, and i do
>>>>>>>> /so/ love having your dumb ass bounce each time i kick it - i'll
>>>>>>>> miss you. much better than video games.
>>>>>>>>
>>>>>>>> bye bye retard!
>>>>>>> Have a great vacation, jim.
>>>>>> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
>>>>>> checking on you - just not as often.
>>>>> Your weird stalking behavior seems to be generalizing.
>>>> "generalizing"??? is that like generalized retardation?
>>> Generalizing in that you are expanding from stalking Jobst to stalking
>>> me as well.
>>>
>>>>>> and quit playing to the peanut gallery with this brown-nosery.
>>>>>> you're still a retard, just one with less self respect.
>>>>> You still don't get it, jim.
>>>> do i understand the apparent need to brown nose someone you've been
>>>> calling a liar? short of retardation, no i don't.
>>> Clearly you don't.
>>>
>>>>> Anyway, have a great vacation.
>>>> i will. but you can fuck off. retard.
>>> Some people are too screwed up to even allow civility.
>> calling someone a liar because you're too fucking retarded to understand
>> what they say is hardly civil. and quit all this "but i'm just trying
>> to be reasonable" bullshit masquerade. you're too fucking retarded to
>> pull it off.
>
> I am reasonable,
no you're not! you pick fights just because you want to. you're
incapable of any technical argument. all you do is present uninformed
opinion. when confronted with facts that contradict, you deny and call
the presenter a liar. occasionally, you go through a masquerade of
asking questions like you're "trying to be reasonable", only to revert
to your original premise having wasted a bunch of time. and if that
doesn't work, you brown-nose. you're a fucking retard timmy. one of
those dumb-asses that gets drunk and picks fights in a bar on a friday
night. simply a fucking retard.
> jim, which is what you don't understand.
>
> Enjoy your vacation. I'll be enjoying mine, the annual 4th of July
> college reunion party that we've been having since 1983. Hanging out
> with old friends is such a treat!
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 27 Jun 2007 18:15:21
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <S_WdnfdwAorr8h_bnZ2dnUVZ_qWvnZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Tim McNamara wrote:
> > In article <cc-dnQRhDMW5dRzbnZ2dnUVZ_gqdnZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> >> Tim McNamara wrote:
> >>> In article <TeSdndPX6_4AQRzbnZ2dnUVZ_g2dnZ2d@speakeasy.net>,
> >>> jim beam <spamvortex@bad.example.net> wrote:
> >>>
> >>>> Tim McNamara wrote:
> >>>>> In article <8qudnT5TvKlcPx3bnZ2dnUVZ_tadnZ2d@speakeasy.net>,
> >>>>> jim beam <spamvortex@bad.example.net> wrote:
> >>>>>
> >>>>>> Tim McNamara wrote:
> >>>>>>>> anyway, timmy boy, i'm off for a summer vacation soon. that
> >>>>>>>> means i may not be able to taunt you full time for a week or
> >>>>>>>> two. use the time constructively won't you? [rhetorical] but
> >>>>>>>> i'll check in when i can. vacation is about having fun, and i do
> >>>>>>>> /so/ love having your dumb ass bounce each time i kick it - i'll
> >>>>>>>> miss you. much better than video games.
> >>>>>>>>
> >>>>>>>> bye bye retard!
> >>>>>>> Have a great vacation, jim.
> >>>>>> /my/ vacation doesn't mean /you/ get one, retard. i'll still be
> >>>>>> checking on you - just not as often.
> >>>>> Your weird stalking behavior seems to be generalizing.
> >>>> "generalizing"??? is that like generalized retardation?
> >>> Generalizing in that you are expanding from stalking Jobst to stalking
> >>> me as well.
> >>>
> >>>>>> and quit playing to the peanut gallery with this brown-nosery.
> >>>>>> you're still a retard, just one with less self respect.
> >>>>> You still don't get it, jim.
> >>>> do i understand the apparent need to brown nose someone you've been
> >>>> calling a liar? short of retardation, no i don't.
> >>> Clearly you don't.
> >>>
> >>>>> Anyway, have a great vacation.
> >>>> i will. but you can fuck off. retard.
> >>> Some people are too screwed up to even allow civility.
> >> calling someone a liar because you're too fucking retarded to understand
> >> what they say is hardly civil. and quit all this "but i'm just trying
> >> to be reasonable" bullshit masquerade. you're too fucking retarded to
> >> pull it off.
> >
> > I am reasonable,
>
> no you're not! you pick fights just because you want to. you're
> incapable of any technical argument. all you do is present uninformed
> opinion. when confronted with facts that contradict, you deny and call
> the presenter a liar. occasionally, you go through a masquerade of
> asking questions like you're "trying to be reasonable", only to revert
> to your original premise having wasted a bunch of time. and if that
> doesn't work, you brown-nose. you're a fucking retard timmy. one of
> those dumb-asses that gets drunk and picks fights in a bar on a friday
> night. simply a fucking retard.
>
>
> > jim, which is what you don't understand.
As I said. Cheers, jim. <plonk >
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Date: 27 Jun 2007 17:18:26
From: Bill Sornson
Subject: Re: High Speed Shimmy
|
Tim McNamara wrote:
> As I said. Cheers, jim. <plonk>
THANK GOD ALMIGHTY! OUR LONG (ENDLESS) USENET NIGHTMARE IS (MAY BE) OVER!!!
Bill "now learn how to snip, both of youse" S.
|
| | | | | | | | | | | | | | | | | | | | | | |
Date: 24 Jun 2007 21:43:14
From: Bill Sornson
Subject: Re: High Speed Shimmy
|
Belly Dancer!
(Thread-ending attempt. On topic...sorta.)
Bill "don't make me put the *14 KBs* back" S.
|
| | | | | | | | | | | | | | | | | | | | | | | |
Date: 25 Jun 2007 06:09:23
From: jim beam
Subject: Re: High Speed Shimmy
|
Bill Sornson wrote:
> Belly Dancer!
>
> (Thread-ending attempt. On topic...sorta.)
>
> Bill "don't make me put the *14 KBs* back" S.
>
>
no dancing on the coffin yet bill - i'm not in it.
|
| | | | | | | | |
Date: 22 Jun 2007 06:20:15
From: jim beam
Subject: Re: High Speed Shimmy
|
Mike Jacoubowsky wrote:
>>>>> This comes up so often at my end of the business. We had one person who
>>>>> was terrified there was something very wrong with her bike because she
>>>>> could get it to shimmy/wobble at 38 mph descending this one particular
>>>>> road when there was a crosswind on a cold day. *All* those things had
>>>>> to exist for the shimmy to occur. And yet it was the bike at fault.
>>>> it is. bike shouldn't do it under any circumstances. the resonance of
>>>> the frame and wheels should be different, not coincident.
>>> A bike is not stable without a rider on it. Do you actually disagree with
>>> this?
>> in that the contact patch of the tire trails behind the fork angle's
>> intersection with the road, yes it is inherently stable.
>
> So you could give the bike a push, without a rider on it, and it would go
> exactly how far before falling over?
the bike system is self-centering. if you're on dead flat terrain and
you had a frictionless headset, it would go in a straight line until
forward motion decreased to the point where self-centering was not quick
enough to prevent topple. but that's not instability of the steering
system.
>
> in that the
>> spring constants of both frame and tires give resonant frequencies well
>> above any frequency that can gain any significant amplitude, yes, it is
>> inherently stable.
>>
>>> And, if you don't, do you understand the ramifications of it?
>> you're working with incomplete information.
>
> What information did I leave out?
it's not what you left out - it's what you didn't take in in the first
place. bikes are inherently stable.
>
>>> Are you suggesting that a shaking rider should have no effect on a bike's
>>> resistance to shimmy?
>> the rider should not be able to make the bike shimmy. with rider load,
>> the resonance of the frame and of the wheels should not be coincident.
>> period. many old fashioned steel frames /do/ shimmy because their
>> torsional stiffness is not very high, and in the old days of undished
>> wheels, it wasn't as much of a problem, but now, with 10-speed
>> ultra-dished wheels, it's a big deal. if we can't have un-dished wheels,
>> we can have torsionally stiff frames where their designer has paid
>> attention to this stuff. no excuses.
>
> So you believe flimsy wheels are the culprit?
not solely, but stiff wheels definitely help. one of my bikes would
shimmy at 15mph and 30mph. i was able to remove the 15 and
substantially reduce the 30 with a stiffer [but otherwise identical]
wheel. simply used 2.0mm straight gauge spokes drive side rear.
> I used to think so too. But
> after changing out wheels (lighter wheels exchanged for much-beefier,
> stiffer versions) for a number of people, without cure, that didn't appear
> to be the answer. I had much better success by changing the position of the
> handlebars.
that'll change some of the loading dynamics, but it's not a "cure".
>
> That's not to say that large frames aren't far more prone to shimmy than
> smaller ones. You're absolutely correct about that. But that wasn't the
> issue for the particular case I referenced. I didn't include the frame size;
> it was 56cm, center-to-top.
let me guess. steel frame. "standard" tube diameters.
>
> Oops, I left out one other piece of information. The person whose bike
> shimmied that I mentioned also had to take one hand off the bars for the
> shimmy to occur. So you've got *5* things that had to exist for her bike to
> shimmy-
>
> #1: Only on this one particular road
> #2: Speed had to be 38mph
> #3: One hand off the bars
> #4: Crosswind
> #5: Cold
geeze, the jobstian "cold" red herring is such a straw grasp. he makes
wild-ass guesses on a whole bunch of subjects he doesn't understand,
that that one's a classic.
>
> So think about what I'm saying here. If it was warm, no shimmy. Hands on
> bars, no shimmy. Any other road, including descents at 38mph, no shimmy.
> Higher or lower speed, no shimmy. No crosswind, no shimmy. For the sake of
> full disclosure, the only thing possibly unusual about this one stretch of
> road is that it's perfectly straight for a fairly good distance. I think
> that pretty much lays everything out on the table.
>
> Still think it was a problem with the bike? (And yes, we did try different
> wheels. She wouldn't consider changing her position on the bike, so we
> couldn't test for that.)
with respect, you don't understand the system. if the frame had
sufficient torsional stiffness, it would not resonate in a frequency
that would be coincident with any part of the application dynamics.
stiffer wheels definitely help because at least /their/ resonant
frequency shifts a bit and becomes less coincident with the frame.
where the two are matched, they're killers. but the real cure is the
frame. most large scale manufacturers seem to have figured that out
these days. not many of the artisans have though.
|
| | | | | | | | |
Date: 22 Jun 2007 16:21:07
From: Michael Warner
Subject: Re: High Speed Shimmy
|
On Fri, 22 Jun 2007 05:24:33 GMT, Mike Jacoubowsky wrote:
> Still think it was a problem with the bike? (And yes, we did try different
> wheels. She wouldn't consider changing her position on the bike, so we
> couldn't test for that.)
I'm curious - would you (or other bike shop owners here) ever give a refund
to someone with shimmy problems on one of your bikes, assuming the
bike wasn't faulty in any way?
I ask because a friend of mine tried two different (carbon) bikes from a
local shop after paying for the first, shimmied on both, asked for a refund
and was refused. He ended up taking the first bike and adapting to the
different geometry and feel, and AFAIK rarely has that problem now.
--
Home page: http://members.westnet.com.au/mvw
|
| | | | | | | | | |
Date: 22 Jun 2007 12:24:18
From: David L. Johnson
Subject: Re: High Speed Shimmy
|
Michael Warner wrote:
> On Fri, 22 Jun 2007 05:24:33 GMT, Mike Jacoubowsky wrote:
>
>> Still think it was a problem with the bike? (And yes, we did try different
>> wheels. She wouldn't consider changing her position on the bike, so we
>> couldn't test for that.)
>
> I'm curious - would you (or other bike shop owners here) ever give a refund
> to someone with shimmy problems on one of your bikes, assuming the
> bike wasn't faulty in any way?
>
> I ask because a friend of mine tried two different (carbon) bikes from a
> local shop after paying for the first, shimmied on both, asked for a refund
> and was refused. He ended up taking the first bike and adapting to the
> different geometry and feel, and AFAIK rarely has that problem now.
>
It's a bit disappointing to still see so little understanding of shimmy.
Shimmy is not caused by a single thing, but by the chance combination
of the various pieces that go into the system, and this includes,
significantly, the rider. No bike design (at least for a bike under 40
pounds) could eliminate the possibility of shimmy for all riders under
all circumstances. And, if you do experience shimmy, and make any
change (position, tires, wheels, frame, etc.), you will change the
system, and that may be enough to stop the shimmy.
I regularly experienced shimmy with my first road bike. I have seen
others have really bad shimmy; one quite recently. For all the
scariness, it's curious that very few riders actually fall from a shimmy.
What I finally learned, and what I tell people to do, is to simply get
the weight off the saddle if you start to shimmy. Whatever combination
of components managed to arrive at that resonance that produces the
shimmy, the resulting motion is rotating about the seat tube (that's why
the front of the bike wobbles back and forth, it is oscillating around
the axis of the seat tube). Removing one's butt from the saddle removes
the anchor for that rotation, and it stops. Of course, some guy with a
death grip on the bars shimmying downhill at 40+mph is not going to
listen to that, but it works. I also find that I descend better with my
weight on the pedals rather than on the saddle.
--
David L. Johnson
As far as the laws of mathematics refer to reality, they are not
certain, and as far as they are certain, they do not refer to reality.
-- Albert Einstein
|
| | | | | | | | | | |
Date: 22 Jun 2007 13:16:04
From: Tim McNamara
Subject: Re: High Speed Shimmy
|
In article <pLWdnSQLGek0aubbnZ2dnUVZ_t-mnZ2d@ptd.net >,
"David L. Johnson" <david.johnson@lehigh.edu > wrote:
> No bike design (at least for a bike under 40 pounds) could eliminate
> the possibility of shimmy for all riders under all circumstances.
jim beam has told you otherwise: no bike should shimmy ever. When will
the bike industry learn?
|
| | | | | | | | | |
Date: 22 Jun 2007 09:13:23
From: Mike Jacoubowsky
Subject: Re: High Speed Shimmy
|
>> Still think it was a problem with the bike? (And yes, we did try
>> different
>> wheels. She wouldn't consider changing her position on the bike, so we
>> couldn't test for that.)
>
> I'm curious - would you (or other bike shop owners here) ever give a
> refund
> to someone with shimmy problems on one of your bikes, assuming the
> bike wasn't faulty in any way?
>
> I ask because a friend of mine tried two different (carbon) bikes from a
> local shop after paying for the first, shimmied on both, asked for a
> refund
> and was refused. He ended up taking the first bike and adapting to the
> different geometry and feel, and AFAIK rarely has that problem now.
As you can imagine, it's a tough problem. My very first ride on a 1992 Trek
5200 was the Steinbeck Century. Rode great until we got to the steep Los
Laureles Grade connecting Carmel Valley with Laguna Seca. About a third of
the way down the bike & I developed a horrendous shimmy... worst I'd ever
experienced. I stopped, pulled off the road and inspected everything very
carefully. No low tires, wheels fine, frame fine. Took a minute or two to
compose myself and continued. That was the only time that happened to me,
ever, on that bike. Apparently all I did was change my position on it ever
so slightly and it went completely away. I know of some customers who would
have "given up" on a bike after that first (and only) instance. To my way of
thinking, it's more like adapting to a car with anti-lock brakes after
having driven for ages with standard ones. You have to re-learn things a
bit, because backing off now & then on the braking won't stop you very fast,
and all you need to do to stop quickly (without locking up the brakes) is
apply firm, continuous force.
I did have a customer who bought a Klein from us, a bike known to be *very*
stiff laterally. 58cm, so large, but not huge. He got scared of it from a
ride where something happened causing a shimmy, and just totally lost
confidence in it. I tried all manner of things, but it wasn't going to
matter. He was expecting it to shimmy, and gosh, what do you know, it did. I
actually traded a frame I had for it (a carbon Trek from my own stable) and
voila, no more shimmy. Ever. And his frame? One of our staff, about the same
height & weight as the customer, has been using it for two years. Solid as a
rock.
As you can imagine, I'm incredibly thankful that such situations are quite
rare.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | | | | | |
Date: 21 Jun 2007 21:59:34
From: jim beam
Subject: Re: High Speed Shimmy
|
jim beam wrote:
> Mike Jacoubowsky wrote:
>>>> This comes up so often at my end of the business. We had one person
>>>> who was terrified there was something very wrong with her bike
>>>> because she could get it to shimmy/wobble at 38 mph descending this
>>>> one particular road when there was a crosswind on a cold day. *All*
>>>> those things had to exist for the shimmy to occur. And yet it was
>>>> the bike at fault.
>>> it is. bike shouldn't do it under any circumstances. the resonance
>>> of the frame and wheels should be different, not coincident.
>>
>> A bike is not stable without a rider on it. Do you actually disagree
>> with this?
>
> in that the contact patch of the tire trails behind the fork angle's
> intersection with the road, yes it is inherently stable. in that the
> spring constants of both frame and tires
whoops! "frame and wheels" - not tires.
> give resonant frequencies well
> above any frequency that can gain any significant amplitude, yes, it is
> inherently stable.
>
>> And, if you don't, do you understand the ramifications of it?
>
> you're working with incomplete information.
>
>> Are you suggesting that a shaking rider should have no effect on a
>> bike's resistance to shimmy?
>
> the rider should not be able to make the bike shimmy. with rider load,
> the resonance of the frame and of the wheels should not be coincident.
> period. many old fashioned steel frames /do/ shimmy because their
> torsional stiffness is not very high, and in the old days of undished
> wheels, it wasn't as much of a problem, but now, with 10-speed
> ultra-dished wheels, it's a big deal. if we can't have un-dished
> wheels, we can have torsionally stiff frames where their designer has
> paid attention to this stuff. no excuses.
|
| | |
Date: 19 Jun 2007 22:40:08
From: Troll Report
Subject: Re: High Speed Shimmy
|
On 20 Jun 2007 01:25:58 GMT, jobst.brandt@stanfordalumni.org wrote:
> Matt Grath writes:
>
>> I know this is a well worn topic, but, I've experienced shimmy with
>> my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been
>> riding the same hills for 15 years with no problems (for the past 8
>> years on Cannondale, which, sadly developed a cracked frame). The
>> shop tightened the spokes, which helped but did not solve the
>> problem. Anyway, the point of the post is to poll folks - is this a
>> Lightspeed issue?
>
> You didn't say whether the shimmy occurs riding no-hands or whether
> you experience it with hands on the bars.
Troll-o-meter says: 3.2
In what universe to you live in? One in which riding no-hands at 35-40mph
is common enough that you'd think it's valid that this point should be
clarified?
|
| | | |
Date: 20 Jun 2007 14:53:29
From:
Subject: Re: High Speed Shimmy
|
someone writes:
>>> I know this is a well worn topic, but, I've experienced shimmy
>>> with my new Lightspeed Terramo at 35 - 40mph. I'm 48 and have
>>> been riding the same hills for 15 years with no problems (for the
>>> past 8 years on Cannondale, which, sadly developed a cracked
>>> frame). The shop tightened the spokes, which helped but did not
>>> solve the problem. Anyway, the point of the post is to poll folks
>>> - is this a Lightspeed issue?
>> You didn't say whether the shimmy occurs riding no-hands or whether
>> you experience it with hands on the bars.
> Troll-o-meter says: 3.2
> In what universe to you live in? One in which riding no-hands at
> 35-40mph is common enough that you'd think it's valid that this
> point should be clarified?
I guess you don't ride bike or you would know that max speeds on fast
descents are achieved with hands on the bar stem in a tight crouch.
Even in that position the soft mass of the hands on the stem suppress
shimmy for most bicycles.
Just the same coasting at 40mph riding no-hands in common among the
people with whom I ride. Typically coasting down CAL HWY84 to La
Honda is a 40mph descent that rolls well sitting up with hands behind
ones back.
I've noticed that riders sneer incredibly when I ask whether their
bicycle rides straight when ridden no-hands, because I note that the
wheels are skewed to one another. The response often is "I don't ride
no-hands!" in a tone as if I had asked whether they ride without a
helmet.
Where have all the young folks of bicycling gone?
http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
Jobst Brandt
|
| | | | |
Date: 21 Jun 2007 00:02:20
From:
Subject: Re: High Speed Shimmy
|
On 20 Jun 2007 14:53:29 GMT, jobst.brandt@stanfordalumni.org wrote:
[snip]
>Where have all the young folks of bicycling gone?
>
>http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
>Jobst Brandt
Dear Jobst,
I chanced upon this picture while looking for bicycle pictures in the
Denver Museum online archive of western photos and thought of your
post for some reason.
I assume that's you, second from the right in the cap and knickers,
listening to the other five fellows at Stanford asking where have all
the young folks of bicycling gone:
http://photoswest.org:8080/cgi-bin/cw_cgi?fullRecord+16444+594+26219+1+0
The full size view shows your bike on the extreme left:
http://photoswest.org/cgi-bin/imager?00130291+C-291
Cheers,
Carl Fogel
|
| | | | | |
Date: 21 Jun 2007 17:54:33
From:
Subject: Re: High Speed Shimmy
|
Carl Fogel writes:
http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
> I chanced upon this picture while looking for bicycle pictures in
> the Denver Museum online archive of western photos and thought of
> your post for some reason.
> I assume that's you, second from the right in the cap and knickers,
> listening to the other five fellows at Stanford asking where have
> all the young folks of bicycling gone:
That's my front porch at the start of a typical Sunday ride, the names
of actors are below the picture. I'm in the blue sweater with white
stripes in the background as the caption indicates.
http://photoswest.org:8080/cgi-bin/cw_cgi?fullRecord+16444+594+26219+1+0
This URL doesn't produce a picture for me at this time.
> The full size view shows your bike on the extreme left:
> http://photoswest.org/cgi-bin/imager?00130291+C-291
Just run the slide show and stop it on the picture you want to
investigate.
Jobst Brandt
|
| | | | | | |
Date: 21 Jun 2007 11:59:32
From:
Subject: Re: High Speed Shimmy
|
On 21 Jun 2007 17:54:33 GMT, jobst.brandt@stanfordalumni.org wrote:
>Carl Fogel writes:
>
> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
>> I chanced upon this picture while looking for bicycle pictures in
>> the Denver Museum online archive of western photos and thought of
>> your post for some reason.
>
>> I assume that's you, second from the right in the cap and knickers,
>> listening to the other five fellows at Stanford asking where have
>> all the young folks of bicycling gone:
>
>That's my front porch at the start of a typical Sunday ride, the names
>of actors are below the picture. I'm in the blue sweater with white
>stripes in the background as the caption indicates.
>
> http://photoswest.org:8080/cgi-bin/cw_cgi?fullRecord+16444+594+26219+1+0
>
>This URL doesn't produce a picture for me at this time.
>
>> The full size view shows your bike on the extreme left:
>
>> http://photoswest.org/cgi-bin/imager?00130291+C-291
>
>Just run the slide show and stop it on the picture you want to
>investigate.
>
>Jobst Brandt
Dear Jobst,
Alas, the Denver site is annoyingly intermittent. A direct link seems
to work better:
http://photoswest.org/photos/00130251/00130291.jpg
Cheers,
Carl Fogel
|
| | | | |
Date: 20 Jun 2007 16:56:37
From: Bill
Subject: Re: High Speed Shimmy
|
jobst.brandt@stanfordalumni.org wrote:
>
> I guess you don't ride bike or you would know that max speeds on fast
> descents are achieved with hands on the bar stem in a tight crouch.
> Even in that position the soft mass of the hands on the stem suppress
> shimmy for most bicycles.
I had a shimmy problem once but it was on a motorcycle and not a
bicycle. Riding my Kawasaki 750cc suicide bike up highway 17 to Santa
Cruz at 90 MPH it had a nasty shimmy in the turns at that speed, mostly
left turns. I took it back to the dealer and it turned out to be a bad
run of tires, Pirelli I think, and replacing them with Dunlops cured the
problem. The tire issue may or may not apply to bicycles, but that is
the only time I have had a shimmy problem on the road.
>
> Just the same coasting at 40mph riding no-hands in common among the
> people with whom I ride. Typically coasting down CAL HWY84 to La
> Honda is a 40mph descent that rolls well sitting up with hands behind
> ones back.
That reminds me of highway 9 coasting down from summit road back to
Saratoga where 40 MPH was on the slower sections and could be done
sitting up and no hands. Getting into a crouch I used to pass cars going
down at who knows what speed, but the drivers sure did a double take.
This was in 1963 on an even older Peugeot ten speed.
>
> I've noticed that riders sneer incredibly when I ask whether their
> bicycle rides straight when ridden no-hands, because I note that the
> wheels are skewed to one another. The response often is "I don't ride
> no-hands!" in a tone as if I had asked whether they ride without a
> helmet.
>
> Where have all the young folks of bicycling gone?
America, Home of the brave, land of the free sissies?
>
> http://www.geocities.com/rayhosler/coastrangeslides/coastrange.html
>
> Jobst Brandt
Bill Baka
Side note. I saw a news article that said car fatalities are climbing
again because the drivers seem to think that the air bag and other
features will protect them no matter how stupidly they drive.
I don't think air bags count when you hit a semi or train.
|
| |
Date: 19 Jun 2007 21:25:32
From: John Forrest Tomlinson
Subject: Re: High Speed Shimmy
|
On Tue, 19 Jun 2007 18:18:48 -0700, mgrath@optonline.net wrote:
>I know this is a well worn topic, but, I've experienced shimmy with my
>new Lightspeed Terramo at 35 - 40mph. I'm 48 and have been riding the
>same hills for 15 years with no problems (for the past 8 years on
>Cannondale, which, sadly developed a cracked frame). The shop
>tightened the spokes, which helped but did not solve the problem.
>Anyway, the point of the post is to poll folks - is this a Lightspeed
>issue?
Litespeed.
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************
|
|
