Aluminum frame fatigue???
a...@novice.uwaterloo.ca
I'm wondering if anyone has ridden an aluminum frame long enough to
know how it stands the test of time.
I've been told by someone that aluminum soaks everything up and will
one day reach its limit and fail. I would like to verify this
property of aluminum.
I've also recently heard that Klein has changed their warranty to 3
years on their frames. Does anyone know the reason behind this
decision. Is it because they were receiving too many frames? I have
a Klein Rascal from some years back and am not sure how to take this
news.
Any help would be greatly appreciated, thanks.
Please email me at a...@novice.uwaterloo.ca
Garry Lee
This is all from what I read, but aluminium does fatigue, but they say
that a properly designed aluminium bike has a very long life, maybe a
million miles. Who they are, I don't know. I have one aluminium bike. The
rest are steel.
Ronald L. Beldon
I too, am curious about the long term (10 to 20 years) life of
bicycle frame construction materials and methods. My assumption is that
aluminum frames, in general, will depreciate through fatigue more
quickly
than other frame types. What about carbon fiber(CF) tube lugged and
monocoque (OCLV) frames? What is the life of the epoxy resin? Would
a CF frame with the normally accumulated micro cracks obtained even
in normal(non-racing) riding eventually lead to the collapse of the CF
tubes after 10 to 20 years? I also assume that titanium will hold up
as long as steel cro-moly if the joints make it through the first year.
I would appreciate comments by any or all materials engineers on
the subject. Oh well, back to my nearly 20-year old R-531 Paramount.
Thanks
Tho X. Bui (bleep@mwci.net)
Garry Lee wrote:
>
> This is all from what I read, but aluminium does fatigue, but they say
> that a properly designed aluminium bike has a very long life, maybe a
> million miles.
A well built aluminum bike will outlast a poorly built steel bike.
Everything can fail by fatigue. Most of the time, it's the rider.
tho
B17 GUY
I've got a 10 year old road bike and it has carried all 225lbs 6'3" of me
with no sign of wear and tear except a few scratches. I also have a 'dale
tandem and a M.B. all are alive and doing just fine.
Erik Speckman
a...@novice.uwaterloo.ca wrote:
>
> I'm wondering if anyone has ridden an aluminum frame long enough to
> know how it stands the test of time.
It doesn't say much about the entire picture but a weld on a friends
cannondale mountain bike broke where one of the chain stays met the
bottom bracket. He was a fairly big guy (225lbs) and the bike was only
a few years old.
Brooks Magruder
Erik Speckman wrote:
>
> a...@novice.uwaterloo.ca wrote:
> >
> > I'm wondering if anyone has ridden an aluminum frame long enough to
> > know how it stands the test of time.
>
i have a 14 year old vitus979 "racing" alum frame that i strapped
paniers onto & road over cobble stone streets of europe.
i commuted with this bike for 5 years, i still ride it almost
every day. it's still seems fine to me. of course, there
maybe some surprise catastrophe awaiting my next 45mph downhill
run...
- brooks
Shane Grimm
I have a 1991 Trek 8000 still riding strong after occassional weekend trail
bashing and frequent weekday commuting.
And what about all the old Aluminum planes still flying about? Why aren't
they crashing more often with all that stressed aluminum? ;)
Judith Manson
Garry Lee <gl...@iol.ie> wrote:
>This is all from what I read, but aluminium does fatigue, but they say
>that a properly designed aluminium bike has a very long life, maybe a
>million miles. Who they are, I don't know. I have one aluminium bike. The
>rest are steel.
I own a canondale 3.0 which started to corrode. It was due to the
original paint chipping and the water and sweat getting underneath the
paint. The fix was to repaint it. Since then I have had no problems
with the aluminium corroding
Dario Gasbarra
Erik Speckman (espe...@halcyon.com) wrote:
: a...@novice.uwaterloo.ca wrote:
: >
: > I'm wondering if anyone has ridden an aluminum frame long enough to
: > know how it stands the test of time.
: It doesn't say much about the entire picture but a weld on a friends
: cannondale mountain bike broke where one of the chain stays met the
: bottom bracket. He was a fairly big guy (225lbs) and the bike was only
: a few years old.
I have a 10 years old Alan ciclocross frame. I had once a problem with the
glue (it is glued) but it was not difficulte to repair and now now it works
quite well.
On the other side I must admit that I never liked it too much, the rebound is
not OK and the only good reason to have such a frame is, in my opinion, ot
have something lite if you want run with it on yourself (ciclicross).
But it is only an opinion of course, S. Kelly had an aluminium frame, so...
Best regards,
Stefano Ferri
sas
Sheldon Brown
Shane Grimm wrote:
>
> I have a 1991 Trek 8000 still riding strong after occassional weekend trail
> bashing and frequent weekday commuting.
>
> And what about all the old Aluminum planes still flying about? Why aren't
> they crashing more often with all that stressed aluminum? ;)
I got to work on one of those that had fallen off of a car rack on
the New York Thruway. What a mess! Wheels, cranks, bars, stem, saddle,
all trashed. When I checked the frame alignment, however, it was still
spot on. Those bikes are tanks!
Sheldon "And I'm Not Even A Trek Dealer" Brown
Newtonville, Massachusetts
+---------------------------------------------------------+
| The Law, in its majestic equality, forbids the rich, |
| as well as the poor, to sleep under the bridges, |
| to beg in the streets, and to steal bread. |
| --Anatole France |
+---------------------------------------------------------+
http://www.sheldonbrown.com/biz/hub/
Harris Cyclery, West Newton, Massachusetts
(617) 244-1040 FAX 244-1041
John Thompson
In <01bbaeee$49ac51e0$b6cf...@SGrimm.fin.gov.bc.ca>, "Shane Grimm" <Shane_...@fincc02.fin.gov.bc.ca> writes:
>a...@novice.uwaterloo.ca wrote:
>> I'm wondering if anyone has ridden an aluminum frame long enough to
>> know how it stands the test of time.
>I have a 1991 Trek 8000 still riding strong after occassional weekend trail
>bashing and frequent weekday commuting.
When I worked for Trek during the development of the bonded
aluminum frames we did destructive testing to determine if this
would be a problem. What we found is that a properly designed
Aluminum frame can have a life very comparable to that of a steel
frame, but when it does fail it tends to go from the initial
cracking to complete failure much more quickly than a steel
frame.
>And what about all the old Aluminum planes still flying about? Why aren't
>they crashing more often with all that stressed aluminum? ;)
The FAA has very rigorous maintainance requirements for aircraft.
Parts that are found to be marginal are removed from service and
replaced with good parts. I'm not aware of any similar
requirement for bicycles.
-John (jth...@ibm.net)
sw...@austin.i-link.net
In article <01bbaeee$49ac51e0$b6cf...@SGrimm.fin.gov.bc.ca>,
Shane_...@fincc02.fin.gov.bc.ca says...
>
>I have a 1991 Trek 8000 still riding strong after occassional
weekend trail
>bashing and frequent weekday commuting.
>
Why aren't
>they crashing more often with all that stressed aluminum? ;)
>
>
I was under the impression they regularly inspect those aluminum
structures very carefully and repair when needed.
Kenly Uy - MHNG/W94
sw...@austin.i-link.net wrote:
: In article <01bbaeee$49ac51e0$b6cf...@SGrimm.fin.gov.bc.ca>,
: >And what about all the old Aluminum planes still flying about?
: Why aren't
: >they crashing more often with all that stressed aluminum? ;)
: I was under the impression they regularly inspect those aluminum
: structures very carefully and repair when needed.
You've got it. Aeroplane maintenance is often costly and very meticulous.
Some aero-afficionados tend to compare aircraft to bikes. Not often very
prudent. For wealthy privateers that own "disarmed" fighters (like
Mig17s or something, a 1950s fighter), the costs for maintenance even for
simple planes are astoudingly high.
Bikes go nowhere near the stresses of flying planes, but give you a
picture of what type of dangers may occur on an improperly inspected plane.
Kristan Roberge
"Shane Grimm" <Shane_...@fincc02.fin.gov.bc.ca> wrote:
>
> I have a 1991 Trek 8000 still riding strong after occassional weekend trail
> bashing and frequent weekday commuting.
Ditto. 1991 Rocky Mountain Stratos. Also my bonded '92 Trek 9000 is also
still holding up well (even though alot of the magazines are now
calling it one of the worst designs in history... lots of people
bought it when the magazines were calling it one of the better designs
back in '92). Of course I'd hope than my straight-gauge and overbuilt
tubing at that 7005 frame of my Stratos would last about a decade. As
for my trek, you can't get much stronger than a bonded Easton Program
7075-T6 frame.
> And what about all the old Aluminum planes still flying about? Why aren't
> they crashing more often with all that stressed aluminum? ;)
What, you mean like the DC-3s built during the 40s that are still flying?!?
Raymond Lopiccolo
> "Shane Grimm" <Shane_...@fincc02.fin.gov.bc.ca> wrote:
> >
> > I have a 1991 Trek 8000 still riding strong after occassional weekend
trail
> > bashing and frequent weekday commuting.
>
Same here. But my Trek 8000 is the 1989 model. It's done a lot of hard
unsuspended mountain biking. The '89 doesn't have the fancy program
tubeset. It's heavy compared to today's bikes but I think it is
over-engineered. So, it will probably last for some time to come in it's
current role as city bike and for occasional road rides. I even used it
recently to pick up a battery for the car. Isn't that ironic?
Also, the original old style rapid fire shifters still work. The rear
shifter was replaced the week I got the bike. The only glitch is that I
need to give an extra push to to the small lever to shift to a smaller cog
after a shift the other way. For some reason, after shifting to a larger
cog, the next click on the small lever doesn't do anything. Then it will
shift to a smaller cog on each successive click like it's supposed to. I
can live with this for the type of riding I do with this bike.
Ray
Jim Papadopoulos
Kenly Uy - MHNG/W94 <k...@acs.ryerson.ca> writes:
>Bikes go nowhere near the stresses of flying planes, but give you a
strength "aerospace" alloys, and also break. So the stresses
had to be pretty high! probably GREATER than in a
well designed airplane.....
Jim
altavoz
Kristan Roberge wrote:
>
> "Shane Grimm" <Shane_...@fincc02.fin.gov.bc.ca> wrote:
> >
> > I have a 1991 Trek 8000 still riding strong after occassional weekend trail
> > bashing and frequent weekday commuting.
>
> still holding up well (even though alot of the magazines are now
> calling it one of the worst designs in history... lots of people
> bought it when the magazines were calling it one of the better designs
> back in '92). Of course I'd hope than my straight-gauge and overbuilt
> tubing at that 7005 frame of my Stratos would last about a decade. As
> for my trek, you can't get much stronger than a bonded Easton Program
> 7075-T6 frame.
>
> > And what about all the old Aluminum planes still flying about? Why aren't
> > they crashing more often with all that stressed aluminum? ;)
>
> What, you mean like the DC-3s built during the 40s that are still flying?!?
altavoz:
DC-3's ?..40's how about 1933.... thats better.
I was a airframe specialist in the USAF and we dont have welded
airplanes . It's all riveted or bolted or in some fancy fighters
it's glued .
recently a 7000 type aluminum was invented that is weldable
( 7000 types are not normally weldable.)
Carbon fiber is at it's best where it doesnt take a concentrated
load as in a bike. Ti has the most promise , but i see poor eng'
where the stress increases at the joints !!
Steel,Ti,al will all be just as strong 100 years from now,
but your epoxy bonded carb fiber frame will continue to polymerize
with time and make a weaker frame .
______End of text from altavoz___________
altavoz
Kristan Roberge wrote:
>
> altavoz <alt...@worldnet.att.net> wrote:
> > recently a 7000 type aluminum was invented that is weldable
> > ( 7000 types are not normally weldable.)
>
> years.
altavoz: Since i didnt date it , i cant be out of date. "Recently"
to the history of Alum' alloys can easily mean "years"
You are net noise.
altavoz
Jim Papadopoulos wrote:
>
> <and...@inforamp.net> writes:
>
> >poor design, sloppy engeneering, cheep manufacturing are all alowed in
> >bike building. In aerospace you would never get away with some of the
> >sloppy crap that passes as normal in bike building.
>
> So I guess you are supporting my assertion that
> stresses are high?
> .
> In fact, not only are bicycles often UN-intentionally
> underdesigned, this is also the rule: to give bikes
> infinite lives would make them unacceptably heavy.
>
> Jim P.
altavoz: Thats nonsense , bikes are hype today . the frames
dont break cause they're light weight , they break cause of
poor engineering.* I will restate my oppinion that approx'
12 years ago we made a sudden direction change toward HYPE.
Prior to that , any one trying to smoke screen the public
would quickly get hammered by the excellent magazine articles
that showed the truth.
* I even saw a steel frame with individual beads ( tig) like
you must do on alum' cause you'll plate the tungsten if you
dont puddle then pull it away and add the filler rod . ha ha
Maybe the idiot figured "if they do it on alum' ,it's good
for steel too"
....or the bike company that didnt design enuf stiffness in so
they advertize " our frames cushion the ride for ...."
Take apart an expensive pedal and calc the bearing capacity , and
you'll see what i mean HYPE . A $150 pedal could have bearings
that are 1/2 whats required !! I have worked on that problem for
years ( you need rollers and 1 ball bearing to "locate" the
rollers ). You say there's not much rotational friction ? Try
hanging a 150 lbs on the pedal and MEASURE THE FRICTION !!
and...@inforamp.net
Jim Papadopoulos <bicyc...@delphi.com> wrote:
poor design, sloppy engeneering, cheep manufacturing are all alowed in
bike building. In aerospace you would never get away with some of the
sloppy crap that passes as normal in bike building.
Quality Assurance, TFI Aerospace
Jim Papadopoulos
<and...@inforamp.net> writes:
>poor design, sloppy engeneering, cheep manufacturing are all alowed in
>bike building. In aerospace you would never get away with some of the
>sloppy crap that passes as normal in bike building.
Jim Papadopoulos
altavoz <alt...@worldnet.att.net> writes:
>poor engineering.* I will restate my oppinion that approx'
>12 years ago we made a sudden direction change toward HYPE.
>Prior to that , any one trying to smoke screen the public
>would quickly get hammered by the excellent magazine articles
>that showed the truth.
>
era. What do you know about low cycle fatigue, anyway?
Jim P.
Joshua_Putnam
>12 years ago we made a sudden direction change toward HYPE.
>Prior to that , any one trying to smoke screen the public
>would quickly get hammered by the excellent magazine articles
>that showed the truth.
Anyone looking at the history of cycling "innovations" knows
that's bunk. Remember the drilled-out component craze of the
'70s? Teledyne Ti frames? Twisted spokes? Miraculous bent
cranks with no dead spot? (Not to mention all the maintenance
myths perpetuated by "excellent" magazine articles, like the old
tale about splitting cranks if you grease the tapers, or
under-tensioning wheels to provide shock absorption.)
Hype has been part of bicycle marketing since bicycles were
invented.
--
Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
"My other bike is a car."
Used & classic bike parts for sale: finger Joshua...@WolfeNet.com for list.
Campy C-Record pedals, new-in-box w/clips (L) and straps, $95
Gary Helfrich
Organization: West Coast Online, Inc.
Distribution:
and...@inforamp.net wrote:
: poor design, sloppy engeneering, cheep manufacturing are all alowed in
: bike building. In aerospace you would never get away with some of the
: sloppy crap that passes as normal in bike building.
: Quality Assurance, TFI Aerospace
Yeah, but at least we have figured out how to use the shift key and a
spell checker. Aren't QA guys supposed to be a bit more type A?
Since you seem so sure of yourself, try this: Design, build and market a
a full suspension frame that weighs 1.75 kg or less. You have to do this
with no fat government or commercial contracts, and get it done before
the off-shore market rips it off. After you have done this, come back and
share your thoughts with us.
High performance sports equipment has very different design and
engineering goals than aircraft. Just because they are different does
not imply that these standards are higher or lower.
Gary Helfrich
Arctos Machine
Matt Bushore
In article <326330...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
|> Jim Papadopoulos wrote:
|> >
|> > <and...@inforamp.net> writes:
|> >
|> > >bike building. In aerospace you would never get away with some of the
|> > >sloppy crap that passes as normal in bike building.
|> >
|> > stresses are high?
|> > .
|> > In fact, not only are bicycles often UN-intentionally
|> > underdesigned, this is also the rule: to give bikes
|> > infinite lives would make them unacceptably heavy.
|> >
|> > Jim P.
|>
|>
|> dont break cause they're light weight , they break cause of
|> Prior to that , any one trying to smoke screen the public
|> would quickly get hammered by the excellent magazine articles
|> that showed the truth.
Designing for finite life is perfectly valid.
I don't read the magazines, but the *good* designers
I have spoken with do know what is going on.
An inspection procedure is a part of most any critical
application.
A comparison with the aerospace industry should include
the fact the regular inspection and extreme maintenance
requirements are what keep things in check.
Aerospace parts are finite life. They don't break because
they are pulled out of service well before they are expected
to fail (hopefully).
I'm not denying that some bikes are poorly designed.
I've also seen some pretty terrible designs in airplanes.
The Magnesium seat brackets in my dad's Cessna 421 comes
to mind...
|> * I even saw a steel frame with individual beads ( tig) like
|> you must do on alum' cause you'll plate the tungsten if you
|> dont puddle then pull it away and add the filler rod . ha ha
|> Maybe the idiot figured "if they do it on alum' ,it's good
|> for steel too"
Help me to understand what exactly you are saying.
Your description of what is happening is so poor that
I am not sure you fully understand what you are talking about.
I have never heard of "plating the tugsten" and I have been
TIG welding for 3 years.
The beads form automagically if you are using a pulser.
The bead size is a function of input heat, filler rod size,
speed, etc.
|> ....or the bike company that didnt design enuf stiffness in so
|> they advertize " our frames cushion the ride for ...."
Again, one can design for compliance.
|> Take apart an expensive pedal and calc the bearing capacity , and
|> you'll see what i mean HYPE . A $150 pedal could have bearings
|> that are 1/2 whats required !! I have worked on that problem for
|> years ( you need rollers and 1 ball bearing to "locate" the
|> rollers ). You say there's not much rotational friction ? Try
|> hanging a 150 lbs on the pedal and MEASURE THE FRICTION !!
|>
|>
|>
|> ______End of text from altavoz___________
Thankfully....
Kristan Roberge
and your a fool. Its lucky for you that I spotted your error and not
someone really picky like Gary Helfrich. 7005 has been used for bike
frames since the early 80s so I guess a decade could be considered
recently, though the alloy itself has existed since the 70s as I recall
so two decades in an industry (aluminum only came into general usage
in the late 1800s) that has only existed for a century might also be
considered recently...
Kenly Uy - MHNG/W94
Jim Papadopoulos (bicyc...@delphi.com) wrote:
: Kenly Uy - MHNG/W94 <k...@acs.ryerson.ca> writes:
:
: >Bikes go nowhere near the stresses of flying planes, but give you a
:
: What can you mean by this? Some bikes use high
: strength "aerospace" alloys, and also break. So the stresses
: had to be pretty high! probably GREATER than in a
: well designed airplane.....
:
: Jim
Oh, yeah, I forgot that high-performance bikes go to 9G acclerations.
Please give me a case where a bike has undergone greater stresses than a
well-designed airplane. The point is, if bikes need to be of aero-grade
metals to be durable, why the hell did we not get catastrophic numbers of
failures with steel bikes?
What's the use of aero alloys if they're machined so thin such that their
best structural strengths are negated? To say that bikes exceed fighter
planes in performance is simply ridiculous.
altavoz
altavoz: UR FULL OF SHIT . And the weldable 7000 is not
strong !! Thats why i pick Titanium as the highest strength/weight
ratio for reasonable cost . You dont know the basics of bike frame
design ! Go back to school .
altavoz
> >Prior to that , any one trying to smoke screen the public
> >would quickly get hammered by the excellent magazine articles
> >that showed the truth.
>
> that's bunk. Remember the drilled-out component craze of the
> '70s? Teledyne Ti frames? Twisted spokes? Miraculous bent
> cranks with no dead spot? (Not to mention all the maintenance
> myths perpetuated by "excellent" magazine articles, like the old
> tale about splitting cranks if you grease the tapers, or
> under-tensioning wheels to provide shock absorption.)
>
> Hype has been part of bicycle marketing since bicycles were
> invented.
>
> --
> Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
> "My other bike is a car."
> Used & classic bike parts for sale: finger Joshua...@WolfeNet.com for list.
> Campy C-Record pedals, new-in-box w/clips (L) and straps, $95
altavoz : UR FULL OF SHIT .
You're picking all those points that we shot down back then and
ur using them to prove that the hype was the same !! you have
to compare the ratio of hyped points then to today !!
Back then Carbon Fiber was shot down for engineering reasons.
Today we see many Carbon Fiber frames !!
Back then , butted down tubes were shot down and immediately
frame builders switched to plain gage . But today no one even
cares !! We're back to butted down tubes . You're not into
engineering , ur into arguing and hype.
altavoz
Gary Helfrich wrote:
> Plate the tungsten? Are you a charter member of the Big Belt Buckle
> Welding Club? Got news for you altavoz old boy, a good welder
> never touches the work with the tungsten, no matter what the material or
> technique. As others have pointed out, the fish scale beads can be a
> result of using pulsed tig rather than dipping the rod.
> Have you ever welded anything? Do you even know how to turn a welding
> machine on? OK, how about a light bulb?
>
> Gary Helfrich
> Arctos Machine
altavoz : Sorry to do this to you . Yes I tig weld and no one
said anything about the tung' touching the work . Got ur foot
out of ur mouth yet ? LOOK CAREFULLY YOU"LL FIND NO POST THAT
SAYS ANYTHING ABOUT TOUCHING THE ELECTRODE TO THE WORK . DUMB SHIT.
One of my skills is elecrical engineering and i could design, and use
any type of welder. I am also a airframe specialist . I also like
structural mechanics ( wanna compete ? ).
Now watch this idiot , i've proven him wrong but it wont fase him
a bit , he'll pretend like he wasnt wrong ...BILL CLINTON
altavoz
a...@novice.uwaterloo.ca wrote:
>
> Thanks for all those that replied my posting. I do agree with what
> altovoz said about hype in the market today. Just look at all the
> different method of rear suspension to see what I mean. Everyone
> claims their system is the best one. But that's besides the
> point. Getting back to aluminm as a material for frames. As I'm sure
> everyone knows, many companies such as Trek/Klein, Cannondale has
> reduced their warranty on their frames to 5 years. I'm interested to
> know if people out there think that 5 years is enough of
> a warranty for an aluminum frame when they can get a lifetime warranty
> on a comparable steel or titanium frame. I've talked to a number of
> people and most seem to agree that the only real benefit of aluminum
> is the weight. Besides with the quality of steel frames today, I
> doubt that is really the case. For all those people that own an
> aluminum frame or any other material, do you feel 5 years is enough
> for a warranty? I personally don't think so, that's why I posted my
> first posting(I have a Klein Rascal). I wasn't expecting such a heated
> debate. Thanks again for all those who wrote.
>
> alan
> a...@novice.uwaterloo.ca
altavoz : The Heated debate would subside if more would study eng' or go
to eng' school ! We have a large number who would like the credit w/o doing
the work . My background is EE but i love Structural mechanics .
altavoz
Matt Bushore wrote:
>
> In article <326330...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
> |> Jim Papadopoulos wrote:
> |> >
> |> > <and...@inforamp.net> writes:
> |> >
> |> > >poor design, sloppy engeneering, cheep manufacturing are all alowed in
> |> > >bike building. In aerospace you would never get away with some of the
> |> > >sloppy crap that passes as normal in bike building.
> |> >
> |> > So I guess you are supporting my assertion that
> |> > stresses are high?
> |> > .
> |> > In fact, not only are bicycles often UN-intentionally
> |> > underdesigned, this is also the rule: to give bikes
> |> > infinite lives would make them unacceptably heavy.
> |> >
> |> > Jim P.
altavoz : ha ha ha ha ha !!! You notice he uses the word "INFINITE"
lives...
> |>
> |> altavoz: Thats nonsense , bikes are hype today . the frames
> |> dont break cause they're light weight , they break cause of
> |> poor engineering.* I will restate my oppinion that approx'
> |> 12 years ago we made a sudden direction change toward HYPE.
> |> Prior to that , any one trying to smoke screen the public
> |> would quickly get hammered by the excellent magazine articles
> |> that showed the truth.
>
> Designing for finite life is perfectly valid.
> I don't read the magazines, but the *good* designers
> I have spoken with do know what is going on.
altavoz: then why dont you let them talk and you shut up.
> An inspection procedure is a part of most any critical
> application.
>
> A comparison with the aerospace industry should include
> the fact the regular inspection and extreme maintenance
> requirements are what keep things in check.
>
> Aerospace parts are finite life. They don't break because
> they are pulled out of service well before they are expected
> to fail (hopefully).
>
> I'm not denying that some bikes are poorly designed.
> I've also seen some pretty terrible designs in airplanes.
> The Magnesium seat brackets in my dad's Cessna 421 comes
> to mind...altavoz : i notice your use of "inspection" how about "engineering"
>
> |> * I even saw a steel frame with individual beads ( tig) like
> |> you must do on alum' cause you'll plate the tungsten if you
> |> dont puddle then pull it away and add the filler rod . ha ha
> |> Maybe the idiot figured "if they do it on alum' ,it's good
> |> for steel too"
> Help me to understand what exactly you are saying.
>
> Your description of what is happening is so poor that
> I am not sure you fully understand what you are talking about.
altavoz :ALL ALUM WELDERS KNOW HOW TO PUDDLE ALUM' THEN FEED THE FILLER ROD !!
> I have never heard of "plating the tugsten" and I have been
> TIG welding for 3 years.
altavoz : Maybe you need 20 or 30 years more.
but most who weld alum will notice that if they get the filler
rod too close to the Tung' they will find the tung' is plated with
alum crap that must be removed . That is why all alum welding is
discontinous , small beads. Steel does not require this technique.
> The beads form automagically if you are using a pulser.
> The bead size is a function of input heat, filler rod size,
> speed, etc.altavoz : You Are FULL OF IT . Tung Inert Gas tig does not pulse !!
>
> |> ....or the bike company that didnt design enuf stiffness in so
> |> they advertize " our frames cushion the ride for ...."
>
> Again, one can design for compliance.
>
> |> Take apart an expensive pedal and calc the bearing capacity , and
> |> you'll see what i mean HYPE . A $150 pedal could have bearings
> |> that are 1/2 whats required !! I have worked on that problem for
> |> years ( you need rollers and 1 ball bearing to "locate" the
> |> rollers ). You say there's not much rotational friction ? Try
> |> hanging a 150 lbs on the pedal and MEASURE THE FRICTION !!
> |>
> |>
> |>
> |> ______End of text from altavoz___________
>
> Thankfully....
altavoz: as long as you hype us , i'll be here .
ALUMINUM AND CARBON FIBER ARE NOT GOOD BIKE FRAME MATERIALS.
"V" brakes are crap ! They still havent figured out MTN bike brakes,
cant's are crap ! Most expensive pedals have shitty bearings.
TELESCOPIC SHOCKS ARE WRONG ! Stop copying motorcycles !!
Motorcycles went to inverted tubes and forgot why they did that !
( to get rid of the triple clamps and make it one piece Magnesium )
You cant use a 12-xx freewheel ! It'll lose races thru friction !!
Too few teeth on the chain !! Campy BB bearings are inferior to the
low cost cart' bearings made by SKF !!
THROW YOUR DAMN CAMPY RELIGION OUT THE WINDOW AND GO TO ENG' SCHOOL !!
altavoz
Jim Papadopoulos wrote:
>
> altavoz <alt...@worldnet.att.net> writes:
>
> >poor engineering.* I will restate my oppinion that approx'
> >12 years ago we made a sudden direction change toward HYPE.
> >Prior to that , any one trying to smoke screen the public
> >would quickly get hammered by the excellent magazine articles
> >that showed the truth.
> >
>
> era. What do you know about low cycle fatigue, anyway?
> Jim P.
altavoz: WELL THAT PROVES IT ( NOT !)
Understanding the characteristics of materials is easy
if you dont touch on fatigue failures !
The resonance of the material, cycles/sec, amplitude of the
stress.... it is less of a science and more imperical than
you think . That is, the facts we have today on fatigue limits
are from experiments as much as from engineering books !!
In other words we still havent tied it down completely .
We all know that brasing a lugged frame involves loosing some
of the "cold work" that was put into the tubes for strength.
This is a very complex analysis that the magazines arent talking
of anymore ! THEY DID 12-14 yrs ago !
Low cycle fatigue is not a big problem , im sure some would like
to label all ruptures as low cycle for they're own reasons . It's
only higher freq fatigue cycles that causes much shorter life than normal.
In fact bikes suffer very low levels. It's simply pushing the frame
close to the upper end of it's elastic region , not operating it at
lower elastic levels and much more cycles.
That is FATIGUE FAILURE , lower stress at millions of cycles rather
than higher stress at the upper end of the proportional limit ( elastic
limit ) at fewer cycles .
Example, steel at 20 hz , at 10kips might fail at several million cycles
and your steel bike would fail at .001 hz at 50kips in 1000
"back and forth" bendings, the later should not be considered fatigue
failure , but a UTS ( ultimate tensile strength) failure. just as .0001
hz at 55kips at 1 back and forth bending s/b considered a UTS failure .
The cycles a bike frame suffer are not 20 hz nor 100 hz nor 10000 hz
and this is required for a fatigue failure. Otherwise it's just a UTS
( or Yield failure...u cant ride it if it's bent).
Alum' is used cause as you thin a tube to make it strong( moment
of inertia) the wall gets so thin on steel ,you could push
a pin thru it. Ratio of MOM of INERTIA to it's wall thickness.
This is where Titanium is king ! It has the low weight ( allows
you to keep a thick wall , and has much higher modulus of elast'
( bend resistance) than Alum !! Yea i know some alum has 60k
or 80 k proportion limit ( another word for mod of elast,strength)
But it cant be welded , TI can . But we must start making the joint
thicker as a lugged frame is . I dont think you'll see failures
in the middle of a tube as often as the joint !
I havent heard of many mentioning that SUSPENSION WILL SAVE
YOUR FRAME ! Suspension dramatically lowers the stress on a frame !
But i predict unsprung,standard front fork( brake design is
easier) with 5" of bar suspen' and a much simpler rear sus'
without links or pins . all springs will be progressive rate .
You cant race w/o dual rate springs ! Damping s/b < 10/90.
In fact if you feel any compression damping , it's probably
wrong . try pushing down a Yamaha 250 mx saddle , u wont feel
a bit of damping . think of it as "the springs resist compression"
..." the damper resists rebound"
In other words , in a very competetive race the top rider
with 0/100 damping ( progress' rate springs) would win easily
but on a 50/50 damped bike he'd do much worse. its not the damping
that prevents bottoming , its progressive spring rates.
Once again you must use a plain gage down tube , the torsion
is too high to thin it down .
I put 6003 metric bearing in my english bb shell to get twice the life
of the other cart' bearing BB . I first tried putting the frame
on the mill but the shell was so flexible that the bore/bar wouldnt
work . So i tapered the 6003 on 1 edge to about .012" then used this
bearing and some Prussian blue to grind out the shell. Sounds crude
but it makes a perfect fit.
Gary Helfrich
: s.inforamp.net> <Z5GzGeU.b...@delphi.com>
<326330...@worldnet.att.net>
Organization: West Coast Online, Inc.
Distribution:
altavoz <alt...@worldnet.att.net> wrote:
: altavoz: Thats nonsense , bikes are hype today . the frames
: dont break cause they're light weight , they break cause of
: poor engineering.* I will restate my oppinion that approx'
: 12 years ago we made a sudden direction change toward HYPE.
: Prior to that , any one trying to smoke screen the public
: would quickly get hammered by the excellent magazine articles
: that showed the truth.
Cool, another person who feels that bicycle magazines are a valid source
of technical information. What FACTS are you basing this observation that
bikes took a turn towards hype 12 years ago? I figure that hype in the
bike industry might even predate the first Italian framebuilder.
: * I even saw a steel frame with individual beads ( tig) like
: you must do on alum' cause you'll plate the tungsten if you
: dont puddle then pull it away and add the filler rod . ha ha
: Maybe the idiot figured "if they do it on alum' ,it's good
: for steel too"
Did your parents give you that stupid name, altavoz, or is your real one
too much of an embarasment to mention in public? Anonymous posters seem
to require a good set of hip waders these days.
Plate the tungsten? Are you a charter member of the Big Belt Buckle
Welding Club? Got news for you altavoz old boy, a good welder
never touches the work with the tungsten, no matter what the material or
technique. As others have pointed out, the fish scale beads can be a
result of using pulsed tig rather than dipping the rod.
Have you ever welded anything? Do you even know how to turn a welding
machine on? OK, how about a light bulb?
If you are going to rant and rave, start backing up your statements with
some facts. This "I saw" or "I read it in a magazine" shit is just that.
I think that it is time for my medication.
Gary Helfrich
Arctos Machine
Jim Papadopoulos
Kenly Uy - MHNG/W94 <k...@acs.ryerson.ca> writes:
>Oh, yeah, I forgot that high-performance bikes go to 9G acclerations.
>
actually confuse ACCELERATION with STRESS???!!! (They even have different
units!)
.
As you probably know, a weak structure will fail under
even 1G gravity or acceleration loads, which means that the
stress was too high! If it fails by plastic collapse,
then the stress was ABOVE the yield stress. That is a
rather high stress level.
.
>Please give me a case where a bike has undergone greater stresses than a
>well-designed airplane. The point is, if bikes need to be of aero-grade
"new style" bicycle parts made unthinkingly out of
exotic materials. If they yielded or fatigued in a
few months, the stress was greater than in a well-designed
airplane.
.
Even the well designed lightweight parts, if used
hard for a few years, will shred. Not because the
stresses were low!
.
Cheers
Jim P.
a...@novice.uwaterloo.ca
Mike Davis
Here's an opinion. Warranties suck. If your frame fails due to a flaw in
manufacture or materials, then it was unsuitable for its intended purpose
and you should be entitled to a replacement anyway. If your frame fails
'cos you rode off a twenty-foot drop-off or hit a tree at 30mph then it's
your fault and you're not entitled to a replacement. 5 years is plenty of
time. Hell, I've only been MTBing for 6.5 and I'm on my fourth frame.
<SWEEPING_GENERALISATION>People who buy trick lightweight exotica are
people who buy new stuff all the time. They'll probably buy a new frame
next year anyway. People who want stuff that lasts choose more
conservatively</SWEEPING_GENERALISATION>.
I've never bought a frame on the strength of the warranty...
Later,
Mike.
--
Mike Davis
mda...@futurenet.co.uk
http://www.futurenet.co.uk/
Mr D.M. Whittle
In article <3261D5...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
> Kristan Roberge wrote:
> >
> > "Shane Grimm" <Shane_...@fincc02.fin.gov.bc.ca> wrote:
> > >
> > > I have a 1991 Trek 8000 still riding strong after occassional weekend trail
> > > bashing and frequent weekday commuting.
> >
> > Ditto. 1991 Rocky Mountain Stratos. Also my bonded '92 Trek 9000 is also
> > still holding up well (even though alot of the magazines are now
> > calling it one of the worst designs in history... lots of people
> > bought it when the magazines were calling it one of the better designs
> > back in '92). Of course I'd hope than my straight-gauge and overbuilt
> > tubing at that 7005 frame of my Stratos would last about a decade. As
> > for my trek, you can't get much stronger than a bonded Easton Program
> > 7075-T6 frame.
> >
> > > And what about all the old Aluminum planes still flying about? Why aren't
> > > they crashing more often with all that stressed aluminum? ;)
> >
> > What, you mean like the DC-3s built during the 40s that are still flying?!?
>
>
>
> altavoz:
>
> DC-3's ?..40's how about 1933.... thats better.
> I was a airframe specialist in the USAF and we dont have welded
> airplanes . It's all riveted or bolted or in some fancy fighters
> it's glued .
> ( 7000 types are not normally weldable.)
Eh?! the 7xxx series are the only ally alloys that dont need heat
treating after welding to regain their strength, so i'd say theyre the
MOST weldable alloys.
>
> Carbon fiber is at it's best where it doesnt take a concentrated
> load as in a bike. Ti has the most promise , but i see poor eng'
> where the stress increases at the joints !!
> Steel,Ti,al will all be just as strong 100 years from now,
> but your epoxy bonded carb fiber frame will continue to polymerize
> with time and make a weaker frame .
>
>
Joshua_Putnam
>The point is, if bikes need to be of aero-grade
>metals to be durable, why the hell did we not get catastrophic numbers of
>failures with steel bikes?
Because lightweight steel bikes use aero grade metals, 4130
chromoly and Reynolds 531, for example.
>What's the use of aero alloys if they're machined so thin such that their
>best structural strengths are negated? To say that bikes exceed fighter
>planes in performance is simply ridiculous.
Nobody said anything about "performance," but rather stresses.
It's quite clear that steel bicycles, which are made from
aircraft alloys, suffer from fatigue failures significantly more
often than airframes do. That's pretty clear indication that
they are under higher stress, isn't it?
Joshua_Putnam
In <541ob2$j...@newsfeed.ftn.net> a...@novice.uwaterloo.ca writes:
>Thanks for all those that replied my posting. I do agree with what
>altovoz said about hype in the market today. Just look at all the
>different method of rear suspension to see what I mean. Everyone
>claims their system is the best one.
But that's nothing new -- Davis Sewing Machine (a/k/a Huffy)
claimed monostay gas shocks were better than sprung chainstays
back around the turn of the century. In the end neither design
was a great success because roads got better. But at the time,
each was the best thing since sliced bread.
>Getting back to aluminm as a material for frames. As I'm sure
>everyone knows, many companies such as Trek/Klein, Cannondale has
>reduced their warranty on their frames to 5 years. I'm interested to
>know if people out there think that 5 years is enough of
>a warranty for an aluminum frame when they can get a lifetime warranty
>on a comparable steel or titanium frame.
A lifetime warranty is a marketing gimmick, not a promise the
product will never fail. The manufacturer calculates the
expected failure rate and prices warranty service into the cost
of a new frame. Ultra-light steel frames will eventually fail
if ridden regularly for enough years, just like ultra-light
aluminum frames. Few riders use their bikes enough to reach that
point.
>For all those people that own an
>aluminum frame or any other material, do you feel 5 years is enough
>for a warranty?
I have six or eight bikes, mostly steel, none with any sort of
warranty on the frame, and it doesn't bother me a bit. Bicycle
frames are not meant to last forever -- inspect them periodically
for incipient failures, then ride bike.
Mike Davis
In article <326470...@worldnet.att.net>, altavoz
<alt...@worldnet.att.net> wrote:
> altavoz : UR FULL OF SHIT .
I do like a considered, rational discussion. Hey ho.
> You're picking all those points that we shot down back then and
> ur using them to prove that the hype was the same !! you have
> to compare the ratio of hyped points then to today !!
> Back then Carbon Fiber was shot down for engineering reasons.
> Today we see many Carbon Fiber frames !!
Technology progresses.
> Back then , butted down tubes were shot down and immediately
> frame builders switched to plain gage . But today no one even
> cares !! We're back to butted down tubes . You're not into
> engineering , ur into arguing and hype.
Aha. So double-butted frame tubing is 'hype', is it? I see.
Hans-Joachim Zierke
Gary Helfrich schrieb am 16.10.96:
> Cool, another person who feels that bicycle magazines are a valid source
> of technical information. What FACTS are you basing this observation that
> bikes took a turn towards hype 12 years ago? I figure that hype in the
> bike industry might even predate the first Italian framebuilder.
According to Archibald Sharp, hype in the bike industry reached a peak
around 1893.
h.
Kristan Roberge
dwh...@liverpool.ac.uk (Mr D.M. Whittle) wrote:
> >
> >
> > altavoz:
> >
> > DC-3's ?..40's how about 1933.... thats better.
> > I was a airframe specialist in the USAF and we dont have welded
> > airplanes . It's all riveted or bolted or in some fancy fighters
> > it's glued .
> > recently a 7000 type aluminum was invented that is weldable
> > ( 7000 types are not normally weldable.)
>
>
> Eh?! the 7xxx series are the only ally alloys that dont need heat
> treating after welding to regain their strength, so i'd say theyre the
> MOST weldable alloys.
>
Actually it depends on the specific 7xxx alloy. 7005 (which is what
most every 7xxx series bike frame is made from including Easton's famous
Program tubes) is easily welded but some 7xxx alloys cannot be welded
at all (at least not at a price which would make it economically feasible
for bike frames... you can even braze aluminum if you wanted to, but
its VERY expensive). 7075 and 7001 are two such alloys, better suited
to machined parts or bonding. You often see 7075T6 being used for such
things as cranksets, chainrings, fork braces, stanchion tubes,
fork crowns and such. 7075T6 is roughly 60% stronger than 7005T6 but the
only frames made out of it in recent years have been some bonded Trek,
Raleigh USA, and Reflex frames, usually using the Easton Program E9
tubeset (E9 was their bonded-only 7075 tubing). My trek 9000 has a
bonded Easton Program E9 7075 tubeset and the main-triangle is only
3 Ibs for a 22" frame. 7001T6 which I have only seen used in ONE bike
part so far (Caramba double-barrel cranksets) is just about the strongest
aluminum alloy availble, falling roughly between Ti CP Grade-4 and Ti
3-2.5 in the strength department, while also being quite a bit lighter.
If it was actually possible to cheaply weld the damn stuff, a sub 2-pound
aluminum frame would be possible.
Matt Bushore
In article <326486...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
|> Jim Papadopoulos wrote:
|> >
|> > altavoz <alt...@worldnet.att.net> writes:
|> >
|> > >poor engineering.* I will restate my oppinion that approx'
|> > >12 years ago we made a sudden direction change toward HYPE.
|> > >Prior to that , any one trying to smoke screen the public
|> > >would quickly get hammered by the excellent magazine articles
|> > >that showed the truth.
|> > >
|> >
|> > Every bike part I've broken (in normal riding) was from that
|> > era. What do you know about low cycle fatigue, anyway?
|> > Jim P.
|>
|>
|> altavoz: WELL THAT PROVES IT ( NOT !)
|>
|>
|> Understanding the characteristics of materials is easy
|> if you dont touch on fatigue failures !
|> The resonance of the material, cycles/sec, amplitude of the
|> stress.... it is less of a science and more imperical than
|> you think . That is, the facts we have today on fatigue limits
|> are from experiments as much as from engineering books !!
No kidding? I would have guessed that all the data
used to write those books was pulled out of thin
air. I guess my friends in the fatigue lab actually
do something?
|> In other words we still havent tied it down completely .
|> We all know that brasing a lugged frame involves loosing some
|> of the "cold work" that was put into the tubes for strength.
|> This is a very complex analysis that the magazines arent talking
|> of anymore ! THEY DID 12-14 yrs ago !
I wonder if this is because bikes aren't lugged anymore?
|> Low cycle fatigue is not a big problem , im sure some would like
|> to label all ruptures as low cycle for they're own reasons . It's
|> only higher freq fatigue cycles that causes much shorter life than normal.
|> In fact bikes suffer very low levels. It's simply pushing the frame
|> close to the upper end of it's elastic region , not operating it at
|> lower elastic levels and much more cycles.
What in the hell are you talking about?
Cycle frequency usually doesn't matter at typical
riding temps/conditions. Elevated temperatures
or highly corrosive enviroments are usually present
before the loading frequency becomes a factor.
|> That is FATIGUE FAILURE , lower stress at millions of cycles rather
|> than higher stress at the upper end of the proportional limit ( elastic
|> limit ) at fewer cycles .
|> Example, steel at 20 hz , at 10kips might fail at several million cycles
|> and your steel bike would fail at .001 hz at 50kips in 1000
|> "back and forth" bendings, the later should not be considered fatigue
|> failure , but a UTS ( ultimate tensile strength) failure. just as .0001
|> hz at 55kips at 1 back and forth bending s/b considered a UTS failure .
|> The cycles a bike frame suffer are not 20 hz nor 100 hz nor 10000 hz
|> and this is required for a fatigue failure. Otherwise it's just a UTS
|> ( or Yield failure...u cant ride it if it's bent).
No,thats incorrect.
1000 Loadings is a low-cycle fatigue failure.
1 loading is a tensile test.
Your definition of "fatigue failure" is completely
unlike any I have ever heard.
Then again, since you aren't a mechanical engineer,
you probably can't be held responsible for much.
Load frequency doesn't enter into defining high-cycle
or low-cycle. Its based on number of cycles (or reversals),
and load levels.
When your work on fatigue is published and stands up to
peer review, I'll believe your bullshit. Until then....
Thomas H. Kunich
In article <5431a9$3...@ratty.wolfe.net>,
Joshua_Putnam <Joshua...@WolfeNET.com> wrote:
>Who were these builders who abandoned butted down tubes, and why
>aren't any of them around today?
You are aware that Reynolds 531 seat tubes are not butted? I forget
if the downtubes are. If you don't want to go to the expense of
butting tubes you just start a rumor that it is DANGEROUS.
David Blake
Kenly Uy - MHNG/W94 wrote:
> Jim Papadopoulos (bicyc...@delphi.com) wrote:
> : Kenly Uy - MHNG/W94 <k...@acs.ryerson.ca> writes:
> : >Bikes go nowhere near the stresses of flying planes, but give you a
> :
> : What can you mean by this? Some bikes use high
> : strength "aerospace" alloys, and also break. So the stresses
> : had to be pretty high! probably GREATER than in a
> : well designed airplane.....
>
>
> well-designed airplane.
Well, if the frame fails and the plane didn't it is not unreasonable to
assume that the frame underwent greater stresses. Stress is a function
of geometry of material and force. Less material for a given force
means more stress. The plane will almost certainly
be built to a larger margin of safety thereby lowering all the
stresses for a given force. Sure, no bike undergoes 8 Gs,
but no plane puts a large force per unit area on a thin
little tube.
--
Dave Blake
dbl...@phy.ucsf.edu
http://www.keck.ucsf.edu/~dblake
Gary Helfrich
:.ryerson.ca>
Organization: West Coast Online, Inc.
Distribution:
Kenly Uy - MHNG/W94 <k...@acs.ryerson.ca> wrote:
: Oh, yeah, I forgot that high-performance bikes go to 9G acclerations.
The acceleration that a part undergoes has very little to do with its
level of performance. A rifle bullet is very reliable when exposed to far
higher accelerations than 9G. Does that make an M16 a higher performance
machine than an F14?
: Please give me a case where a bike has undergone greater stresses than a
: well-designed airplane. The point is, if bikes need to be of aero-grade
: metals to be durable, why the hell did we not get catastrophic numbers of
: failures with steel bikes?
Lots of things are engineered closer to the edge than high performance
aircraft. Look at engines used in top fuel drag racing competition.
The internal parts are being worked to the hairy edge. Designing parts for
a reliable service life measured in seconds is no easy task. It would be
irresponsible for an aircraft designer to push materials as hard as they
are in a well designed bicycle.
Durabilty is not always the hallmark of engineering excellence. Just
because a heavy bike does not fail, how does that imply that it is well
designed? A good design is one that meets all performance goals that
cannot have on extra gram removed from it without compromising these
performance criteria. Most anyone can "design" a relable 5 pound frame.
Lower that to sub three pounds and it starts to get interesting.
: What's the use of aero alloys if they're machined so thin such that their
: best structural strengths are negated? To say that bikes exceed fighter
: planes in performance is simply ridiculous.
You have to define performance in order to make this statement. High end
bikes work the material closer to its yield point than most aircraft.
Aircraft are very complicated expensive machines. Bikes are simple,
elegant ones. It's apples and oranges again. I am still waiting for an
aircraft designer to step in and design a bike that puts the industry in
its place.
Gary Helfrich
Arctos Machine
Joshua_Putnam
>In article <5431a9$3...@ratty.wolfe.net>,
>Joshua_Putnam <Joshua...@WolfeNET.com> wrote:
>>Who were these builders who abandoned butted down tubes, and why
>>aren't any of them around today?
>You are aware that Reynolds 531 seat tubes are not butted?
Sure they are. 531 Competition and Magnum are 0.8/0.5, 531 ST
and 531 All Terrain are 1.0/0.7, all butted. Even their cheap
welded CrMo tubes are available butted -- the standard 501 seat
tube is 0.9/0.6. 531 seat tubes are also available with external
butting and external butting with a flared bottom end.
>I forget if the downtubes are.
All three main tubes are butted even on sets as cheap as 525
CrMo.
Joshua_Putnam
I'd sure like to know when "back then" butted down tubes were
"shot down." Certainly not in the '60s, '70s, or early '80s, the
magical years before the supposed introduction of hype in
bicycles.
Who were these builders who abandoned butted down tubes, and why
aren't any of them around today?
--
Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
"My other bike is a car."
Used & classic bike parts for sale: finger Joshua...@WolfeNet.com for list.
Suntour Alpha-5000 front touring derailleur, 28.6 clamp, new, $8
Mike Davis
In article <326475...@worldnet.att.net>, altavoz
<alt...@worldnet.att.net> wrote:
> altavoz: as long as you hype us , i'll be here .
> ALUMINUM AND CARBON FIBER ARE NOT GOOD BIKE FRAME MATERIALS.
And why would that be then?
> "V" brakes are crap !
Well, there's no major improvement over cantism I'd grant you. They're
hardly 'crap'. They stop the bike. That's what counts.
> They still havent figured out MTN bike brakes,
You, of course, have all the answers. Do tell how 'They' should be doing it.
> cant's are crap !
Do you have some difficulty with brakes in general? Perhaps you ride
everywhere at Mach 4. Or perhaps you can't set them up properly.
> Most expensive pedals have shitty bearings.
Many reasonably priced pedals have perfectly adequate bearings. Your point?
> TELESCOPIC SHOCKS ARE WRONG ! Stop copying motorcycles !!
I'm going to leave this so as to avoid a telescopic/linkage debate. Hey,
they both work after all.
> Motorcycles went to inverted tubes and forgot why they did that !
Motorcycles do not forget. Or remember. Or think. No brains, y'see.
> ( to get rid of the triple clamps and make it one piece Magnesium )
Make what one-piece magnesium, pray tell?
> You cant use a 12-xx freewheel ! It'll lose races thru friction !!
Of course! That's why I've never won a race! Thanks for pointing that out!!
> Too few teeth on the chain !!
I don't know about you, but my chain doesn't have any teeth on it at all.
> THROW YOUR DAMN CAMPY RELIGION OUT THE WINDOW AND GO TO ENG' SCHOOL !!
THROW YOUR DAMN NONSENSE OUT THE WINDOW AND GO, er, AWAY!
Jobst Brandt
Kenly Uy writes:
> Please give me a case where a bike has undergone greater stresses
> than a well-designed airplane. The point is, if bikes need to be of
> aero-grade metals to be durable, why the hell did we not get
> catastrophic numbers of failures with steel bikes?
Ahem! Especially in a "well-designed" airplane the materials have
uniformly low stresses. That's why it is called well designed. Its
the poorly designed machines that have the high stress. I'm sure you
didn't learn ideas of high stress design at Ryerson.
Jobst Brandt <jbr...@hpl.hp.com>
Kevin Locke
Joshua, I hope that I do not misinterpret your meaning in the following
statement :
>Joshua_Putnam wrote:
>
> Nobody said anything about "performance," but rather stresses.
> It's quite clear that steel bicycles, which are made from
> aircraft alloys, suffer from fatigue failures significantly more
> often than airframes do. That's pretty clear indication that
> they are under higher stress, isn't it?
A "clear indication" ?? fatigue failure occurs for a variety of reasons.
Such as improper use of material/ not enough material, using the material
too much ... Bike manufactures want to sell bikes. We as consumers demand
light weight and low cost. Low cost means cutting some corners on the
design, manufacture and inspection (of the material and weld). Low cost
can mean no big computers doing design research.
Aircraft designers spend an incredible amount of money designing a part to
handle a stress or motion (static and dynamic loads) that is predicted.
Then they throw in a factor of safety. The aircraft engineers have very
expensive high speed computers at thier disposal. The manufacture process
is tightly controlled (robotic). Computers inspect the finished product.
Mechanics inspect for fatigue and other failure modes on a regular basis
and replace a part as needed.
We as cyclists get the benefit of the aviation research (a few years later)
in better materials and processes. Al, Ti, metal matrix composites,
graphite, kevlar, ceramics, even boeshield have been tested and perfected
(or thrown out, ie wood) in aircraft. Yes I realize that other disiplines
use "exotic" materials, and that av did not create all of these materials,
but the discussion is at this point.
Al will fatigue more than other metals used in bikes. The failure mode
usually starts at the welds (a crack source). A well made Al frame will
last as long as a well made steel frame. I think that this thread wanted
to know the answer to this. I own 2 steel bikes and 2 Al bikes. I like
all of them.
btw, I am a rocket scientist.
--
******* O- ********
* ,__o *
* _-\-<, *
* (*)/'(*) *
* Kevin Locke *
* klo...@ti.com *
******* O- ********
TedHas
>and...@inforamp.net wrote:
>
>: poor design, sloppy engeneering, cheep manufacturing are all alowed in
>: bike building. In aerospace you would never get away with some of the
>: sloppy crap that passes as normal in bike building.
That's why every year a couple of new companies start up building bikes.
The proprietors are folks recently downsized from aerospace industries or
are ready to strike out on their own. They figure with all that
engineering and exotic materials experience they can take the bike world
by storm--ought to be easy after jet fighters, space craft, whatever. They
bring their vast knowlege to bear on their breakthrough product and sure
enough it breaks through! If we're lucky, they persevere and actually do
get it right and offer something new and worthwhile. But they learn
quickly that a bike ain't as simple as it seem at first. It's a machine
that must endure high stresses while keeping weight low, and must live in
a hostile, wet and gritty environment. Aerospace ain't got a thing on bike
building except lots of money to throw at each problem.
--Ted Haskell
Robert Horvatich
altavoz wrote:
> One of my skills is elecrical engineering and i could design, and use
> any type of welder. I am also a airframe specialist . I also like
> structural mechanics ( wanna compete ? ).
> Now watch this idiot , i've proven him wrong but it wont fase him
> a bit , he'll pretend like he wasnt wrong ...BILL CLINTON
If you are an airframe specialist, why are you unable to differentiate
between loads and stresses? If a part fails due to yielding no matter
what the load, that means the stresses are high enough to cause
yielding. This can and has happened to bicycle frames. Simple
undergad mechanics of materials class describes such details. Yet it
seems an airframe specialist can not comprehend such details.
It appears with your rash of reposts that you are somewhat defensive
about our responses to your misinformed posts. I would also watch who
you call an idiot as you further displaying your ignorance.
As one wise man has said, "It is better to be silent and thought a
fool than to open ones mouth and remove all doubt".
Rob
--
email: |"You can't take life too seriously,
rhor...@ae0119.pd8.ford.com | you don't get out alive." Buggs Bunny
Jobst Brandt
Hajo writes:
Yes, that's like books titled: "The Complete Book on Modern Bicycles",
titles that could as well have come from the last century as the next.
Often, thinking MY era is the acme of something or other, is naive.
Jobst Brandt <jbr...@hpl.hp.com>
Peter Mills
In article <541ob2$j...@newsfeed.ftn.net> a...@novice.uwaterloo.ca writes:
>From: a...@novice.uwaterloo.ca
>Subject: Re: Aluminum frame fatigue???
>Date: Wed, 16 Oct 1996 07:22:39 GMT
>Thanks for all those that replied my posting. I do agree with what
>altovoz said about hype in the market today. Just look at all the
>different method of rear suspension to see what I mean. Everyone
>claims their system is the best one. But that's besides the
>point. Getting back to aluminm as a material for frames. As I'm sure
>everyone knows, many companies such as Trek/Klein, Cannondale has
>reduced their warranty on their frames to 5 years. I'm interested to
>know if people out there think that 5 years is enough of
>a warranty for an aluminum frame when they can get a lifetime warranty
>on a comparable steel or titanium frame. I've talked to a number of
>people and most seem to agree that the only real benefit of aluminum
>is the weight. Besides with the quality of steel frames today, I
>doubt that is really the case. For all those people that own an
>aluminum frame or any other material, do you feel 5 years is enough
>for a warranty? I personally don't think so, that's why I posted my
>first posting(I have a Klein Rascal). I wasn't expecting such a heated
>debate. Thanks again for all those who wrote.
I don't think I'm alone in believing that all good bicycle frames should
have a lifetime warranty. I would never by a Cannondale. Why? Recently I
lived with a room mate who owned a 'Dale. Behind the seat tube there was a
notice instructing the owner of the bicycle to inspect it regularly for
frame fatique, particularly under the down tube. If Cannondale knows that
these failures are occurring, why don't they do something about it, like
make their bikes stronger? Instead, they put some lame sticker on the
frame, and try to hide it from a potential buyer by placing it in the most
inaccessible location possible. This was even a hybrid, a type of bike
which should be designed for utilitarian use, not high performance riding.
Peter Mills
Joshua_Putnam
>Gary Helfrich schrieb am 16.10.96:
>> Cool, another person who feels that bicycle magazines are a valid source
>> of technical information. What FACTS are you basing this observation that
>> bikes took a turn towards hype 12 years ago? I figure that hype in the
>> bike industry might even predate the first Italian framebuilder.
>According to Archibald Sharp, hype in the bike industry reached a peak
>around 1893.
I don't know an exact year, but surely the hype was the strongest
back before cars were common, when bicycles filled all the social
and advertising niches now claimed by motorized vehicles:
personal freedom, ease of transport, social status, recreation,
etc. All the ad techniques used to hype cars after WW II were
used to sell bikes before WW I.
--
Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
"My other bike is a car."
Used & classic bike parts for sale: finger Joshua...@WolfeNet.com for list.
Silca Impero pump w/ultralight Presta head, white, 440mm, NEW, $8
Eric W. Bryant
altavoz (alt...@worldnet.att.net) wrote:
:*
:* altavoz : The Heated debate would subside if more would study eng' or go
:* to eng' school ! We have a large number who would like the credit w/o doing
:* the work . My background is EE but i love Structural mechanics .
:*
:* ______End of text from altavoz___________
I would like to briefly state that not all of us EE's are as big of
morons as this altavoz character.
--
Eric Bryant Electrical Engineering undergraduate
ewbr...@mtu.edu Michigan Technological University
finger ewbr...@kirchhoff1.ee.mtu.edu for various info
Mark Hickey
k...@acs.ryerson.ca (Kenly Uy - MHNG/W94) writes:
> Oh, yeah, I forgot that high-performance bikes go to 9G acclerations.
>
> Please give me a case where a bike has undergone greater stresses than a
> well-designed airplane.
Show me where an airplane has to carry 8-10 times its weight, and
THEN undergo 9G's and I'll be impressed.
Mark Hickey
Habanero Cycles
http://www.cynetfl.com/habanero/
Mark Hickey
Kevin Locke <klo...@ti.com> writes:
> Joshua, I hope that I do not misinterpret your meaning in the following
> statement :
>
> >Joshua_Putnam wrote:
> >
> > Nobody said anything about "performance," but rather stresses.
> > It's quite clear that steel bicycles, which are made from
> > aircraft alloys, suffer from fatigue failures significantly more
> > often than airframes do. That's pretty clear indication that
> > they are under higher stress, isn't it?
>
> A "clear indication" ?? fatigue failure occurs for a variety of reasons.
> Such as improper use of material/ not enough material, using the material
> too much ... Bike manufactures want to sell bikes. We as consumers demand
> light weight and low cost. Low cost means cutting some corners on the
> design, manufacture and inspection (of the material and weld). Low cost
> can mean no big computers doing design research.
>
> Aircraft designers spend an incredible amount of money designing a part to
> handle a stress or motion (static and dynamic loads) that is predicted.
> Then they throw in a factor of safety. The aircraft engineers have very
> expensive high speed computers at thier disposal. The manufacture process
> is tightly controlled (robotic). Computers inspect the finished product.
> Mechanics inspect for fatigue and other failure modes on a regular basis
> and replace a part as needed.
All well and fine, but you're missing a couple key points. First,
aircraft have to be designed with a lot more margin than a bicycle.
Just one or two wing struts cutting loose could bankrupt an aircraft
builder, where most bike frame failures are far less catastrophic.
Second, I don't think you have enough computer power in the airline
industry to do a realistic model of the stresses of a bicycle. "WHAT?!"
you say? Think about the literally infinite number of variables that
you encounter on a typical MTB ride - every rider will drastically alter
the way the bike handles and absorbs punishment, unlike aircraft design,
where you pretty much know what it's going to encounter. It would be
like designing an airplane wing that would stay together if something
that weighed 8-10x as much as the airplane were jumping back and forth
on it while it gyrated over 2 to 8 foot bumps.
Plus, with the standard diamond frame, bike builders have literally
millions of data points of anecdotal evidence about what works. Is that
"scientific".... well, not if your definition is measured by how many
hours it takes a Cray to figure it out.. but it IS scientific in the
same way most medicine has been developed. It's really not that hard
to build a frame that's not going to fall apart, unless you're really
trying to push the edge of the "anecdotal envelope".
PS - I've NEVER had a frame failure.
Camiel Rouweler
altavoz <alt...@worldnet.att.net> wrote:
>Alum' is used cause as you thin a tube to make it strong( moment
>of inertia) the wall gets so thin on steel ,you could push
>a pin thru it. Ratio of MOM of INERTIA to it's wall thickness.
I don't know wether you have a different definition of moment of
intertia from what I have, or this is just complete BS. What would
one care what the moment of inertia of a tube is? They sure aren't
rotating when I ride my bike.
I also never heard of making tubes _stronger_ by making them thinner.
--
Camiel Rouweler (cami...@surf.phys.tue.nl)
"I don't want to be called 'boy' anymore. I find that term
sexist and demeaning!". "How do you want to be called then?"
"I want to be called 'chromosomally advantaged youth." (Calvin&Hobbes)
Paul
In article <5455t8$o...@tuegate.tue.nl>, Camiel Rouweler
<cami...@surf.phys.tue.nl> wrote:
> altavoz <alt...@worldnet.att.net> wrote:
>
> >Alum' is used cause as you thin a tube to make it strong( moment
> >of inertia) the wall gets so thin on steel ,you could push
> >a pin thru it. Ratio of MOM of INERTIA to it's wall thickness.
> I also never heard of making tubes _stronger_ by making them thinner.
A lot of frame maker make the frame stiffer by making the tubes
larger. To maintain the weight, they make the tube thinner.
With a low density material like aluminum, you can get a decent
thickness and still maintain the weight. A higher density material
like steel would have to be thinner to maintain the same weight.
The thinner walls would be suspectible to crushing like a beer can.
Not quite thinner = stronger, but perhaps that's what the other
poster meant.
Don't know what MOM or INERTIA is or have to do with frames.
Mike Davis
In article <PATMILLS.1...@SCIENCE2.watstar.uwaterloo.ca>,
PATM...@SCIENCE2.watstar.uwaterloo.ca (Peter Mills) wrote:
> I don't think I'm alone in believing that all good bicycle frames should
> have a lifetime warranty. I would never by a Cannondale. Why? Recently I
> lived with a room mate who owned a 'Dale. Behind the seat tube there was a
> notice instructing the owner of the bicycle to inspect it regularly for
> frame fatique, particularly under the down tube. If Cannondale knows that
> these failures are occurring, why don't they do something about it, like
> make their bikes stronger? Instead, they put some lame sticker on the
> frame, and try to hide it from a potential buyer by placing it in the most
> inaccessible location possible. This was even a hybrid, a type of bike
> which should be designed for utilitarian use, not high performance riding.
I think you'll find that a lot of alu bikes have these stickers in the
States. The CPSC make manufacturers put them there, like the _really_ lame
one about doing up the QRs properly. Besides, inspecting the frame
regularly for cracks or other damage is good practice whatever the frame
is or what it's made of...
Jeff Stenquist
I'm not trying to defend Cannondale or advocate aluminum, however, I think
something needs to be said about what are commonly called "Lawyer stickers" for
good reason. In the unlikely event that one of cannondale's frames failed for
any reason, some ambulance chasing lawyer could take cannondale to court which
could cost millions in legal fees and settlements etc. These warning stickers
are nothing more than insurance against litigation and don't necessarily have
anything to do with the reliability of the frame. Most new bikes I've seen have
several of these stickers, often giving useless warnings about riding in the rain
or the improper use of skewers.
Basically, don't take them too seriously or read more into them than they're worth.
-Jeff Stenquist
Salt Lake City, Utah
altavoz
Kristan Roberge wrote:
>
> dwh...@liverpool.ac.uk (Mr D.M. Whittle) wrote:
>
> > >
> > >
> > > altavoz:
> > >
> > > DC-3's ?..40's how about 1933.... thats better.
> > > I was a airframe specialist in the USAF and we dont have welded
> > > airplanes . It's all riveted or bolted or in some fancy fighters
> > > it's glued .
> > > recently a 7000 type aluminum was invented that is weldable
> > > ( 7000 types are not normally weldable.)
> >
> >
> > Eh?! the 7xxx series are the only ally alloys that dont need heat
> > treating after welding to regain their strength, so i'd say theyre the
> > MOST weldable alloys.
altavoz ?!!! BS ! No weldable metal has any significant strength
after welding ( w/o heat treatment) . GO TO SCHOOL ,
GET SOME EXPERIENCE !
> Actually it depends on the specific 7xxx alloy. 7005 (which is what
> most every 7xxx series bike frame is made from including Easton's famous
> Program tubes) is easily welded but some 7xxx alloys cannot be welded
> at all (at least not at a price which would make it economically feasible
> for bike frames... you can even braze aluminum if you wanted to, but
> its VERY expensive). 7075 and 7001 are two such alloys, better suited
> to machined parts or bonding. You often see 7075T6 being used for such
> things as cranksets, chainrings, fork braces, stanchion tubes,
> fork crowns and such. 7075T6 is roughly 60% stronger than 7005T6 but the
> only frames made out of it in recent years have been some bonded Trek,
> Raleigh USA, and Reflex frames, usually using the Easton Program E9
> tubeset (E9 was their bonded-only 7075 tubing). My trek 9000 has a
> bonded Easton Program E9 7075 tubeset and the main-triangle is only
> 3 Ibs for a 22" frame. 7001T6 which I have only seen used in ONE bike
> part so far (Caramba double-barrel cranksets) is just about the strongest
> aluminum alloy availble, falling roughly between Ti CP Grade-4 and Ti
> 3-2.5 in the strength department, while also being quite a bit lighter.
> If it was actually possible to cheaply weld the damn stuff, a sub 2-pound
> aluminum frame would be possible.
All weldable Alum has significantly less strength than non weld' .
7075-T6 has much greater strength than the weldable 7xxx Alum.
Which turns us toward Ti as being much more cost effective ( <$5000)
for frames . It's not just 10% or 20% better !
BTW Moment of Inertia was raised in a post about strength. Mom of Inertia
is how much material u have away from the nuetral bend axis. So it's a
measure of stiffness. All the material at the nuetral bend axis makes
something very limp . An I beam has the material pushed out as far as
possible from the nuet bend axis to raise the Mom Of Inertia ( "Io")
altavoz
Mike Davis wrote:
>
> In article <326470...@worldnet.att.net>, altavoz
> <alt...@worldnet.att.net> wrote:
>
> > altavoz : UR FULL OF SHIT .
>
> I do like a considered, rational discussion. Hey ho.
>
> > You're picking all those points that we shot down back then and
> > ur using them to prove that the hype was the same !! you have
> > to compare the ratio of hyped points then to today !!
> > Back then Carbon Fiber was shot down for engineering reasons.
> > Today we see many Carbon Fiber frames !!
>
> Technology progresses.
>
> > frame builders switched to plain gage . But today no one even
> > cares !! We're back to butted down tubes . You're not into
> > engineering , ur into arguing and hype.
>
> Aha. So double-butted frame tubing is 'hype', is it? I see.
IF YOU'LL NOTICE HE DROPPED THE WORD "DOWN" AND CONTINUED WITH
" DOUBLE BUTTED FRAME TUBING" THAT MAKES HIM A LIAR !
My post clearly says DOWN tube . Look for the asterisk * above.
altavoz
Thomas H. Kunich wrote:
>
> In article <5431a9$3...@ratty.wolfe.net>,
> Joshua_Putnam <Joshua...@WolfeNET.com> wrote:
>
> >aren't any of them around today?
altavoz : They are, you dont see them cause you cant see or dont want
to.
>
> You are aware that Reynolds 531 seat tubes are not butted? I forget
> if the downtubes are. If you don't want to go to the expense of
> butting tubes you just start a rumor that it is DANGEROUS.
you're misjudging bike owners( >$600 level) they will quickly
shoot plain gage down ! Seat tubes can be single butted.
Mike Davis
In article <545iiq$2...@news.wco.com>, Gary Helfrich <lap...@wco.com> wrote:
> :ws.wco.com> <326478...@worldnet.att.net>
> Organization: West Coast Online, Inc.
> Distribution:
>
> altavoz <alt...@worldnet.att.net> wrote:
>
> : altavoz : Sorry to do this to you . Yes I tig weld and no one
> : said anything about the tung' touching the work . Got ur foot
> : out of ur mouth yet ? LOOK CAREFULLY YOU"LL FIND NO POST THAT
> : SAYS ANYTHING ABOUT TOUCHING THE ELECTRODE TO THE WORK . DUMB SHIT.
> :
>
> I believe that Ur was an ancient city in the Mid east. I have a big mouth
> but fitting an entire city in it seems unlikely. Even only one foot in
> would be tough.
[Really quite amusing and splendid ripostes snipped]
If anyone is still in any doubt as to the verisimilitude (er, or
something) of 'altavoz', they may find it instructive to hop over to
www.dejanews.com and marvel in his postings to, amongst others,
alt.electrical.engineering (yes, really), alt.female.supremacy (he goes
down _really_ well there) and, er, alt.sex.anal.
altavoz
Mike Davis wrote:
>
> In article <326475...@worldnet.att.net>, altavoz
> <alt...@worldnet.att.net> wrote:
>
> > altavoz: as long as you hype us , i'll be here .
> > ALUMINUM AND CARBON FIBER ARE NOT GOOD BIKE FRAME MATERIALS.
>
> And why would that be then?
>
> > "V" brakes are crap !
>
> Well, there's no major improvement over cantism I'd grant you. They're
> hardly 'crap'. They stop the bike. That's what counts.
altavoz : No its not what counts, riders are complaining about
adjusting the power ( how hard they pull on lever). My brake
has adjustable power cause of "over center" . Do you need an
explain on over center ?
> > They still havent figured out MTN bike brakes,
>
> You, of course, have all the answers. Do tell how 'They' should be doing it.
altavoz : SARCASTIC
> > cant's are crap !
>
> Do you have some difficulty with brakes in general? Perhaps you ride
> everywhere at Mach 4. Or perhaps you can't set them up properly.
>
> > Most expensive pedals have shitty bearings.
>
> Many reasonably priced pedals have perfectly adequate bearings. Your point?
altavoz: THEY ARE NOT ADEQUATE.
> > TELESCOPIC SHOCKS ARE WRONG ! Stop copying motorcycles !!
>
> I'm going to leave this so as to avoid a telescopic/linkage debate. Hey,
> they both work after all.
>
> > Motorcycles went to inverted tubes and forgot why they did that !
>
> Motorcycles do not forget. Or remember. Or think. No brains, y'see.
>
> > ( to get rid of the triple clamps and make it one piece Magnesium )
>
> Make what one-piece magnesium, pray tell?
>
> > You cant use a 12-xx freewheel ! It'll lose races thru friction !!
>
> Of course! That's why I've never won a race! Thanks for pointing that out!!
>
> > Too few teeth on the chain !!
>
> I don't know about you, but my chain doesn't have any teeth on it at all.
>
> > THROW YOUR DAMN CAMPY RELIGION OUT THE WINDOW AND GO TO ENG' SCHOOL !!
>
> THROW YOUR DAMN NONSENSE OUT THE WINDOW AND GO, er, AWAY!
> Mike.
altavoz :We who want the facts want you who distort to go away.
and we're going to hammer you non-techies til you shut up.
altavoz
altavoz : EVERYTHING !! Frame makers are desperately fighting to
get the Mom of inertia higher !! The lack of stiffness ( M of I....
"Io") works only for spokes and others . In spokes we dont want an
extremely high Io cause they need to stretch to allow the adjacent
spokes to take up the load when they arnt perfectly adjusted.
If one spoke is too loose , it will still take some of the
load cause the ones next to it will stretch to force
some of the load on the loose one ...kind of intuitive with rubber bands.
> Paul
> pa...@discordia.org
altavoz
Matt Bushore wrote:
>
> In article <326486...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
> |> Jim Papadopoulos wrote:
> |> >
> |> > altavoz <alt...@worldnet.att.net> writes:
> |> >
> |> > >poor engineering.* I will restate my oppinion that approx'
> |> > >12 years ago we made a sudden direction change toward HYPE.
> |> > >Prior to that , any one trying to smoke screen the public
> |> > >would quickly get hammered by the excellent magazine articles
> |> > >that showed the truth.
> |> > >
> |> >
> |> > Every bike part I've broken (in normal riding) was from that
> |> > era. What do you know about low cycle fatigue, anyway?
> |> > Jim P.
> |>
> |>
> |> altavoz: WELL THAT PROVES IT ( NOT !)
> |>
> |>
> |> Understanding the characteristics of materials is easy
> |> if you dont touch on fatigue failures !
> |> The resonance of the material, cycles/sec, amplitude of the
> |> stress.... it is less of a science and more imperical than
> |> you think . That is, the facts we have today on fatigue limits
> |> are from experiments as much as from engineering books !!
>
> No kidding? I would have guessed that all the data
> used to write those books was pulled out of thin
> air. I guess my friends in the fatigue lab actually
> do something?
altavoz : SARCASM . My point is that magazines are getting paid
to publish hype not good engineering.
> |> In other words we still havent tied it down completely .
> |> We all know that brasing a lugged frame involves loosing some
> |> of the "cold work" that was put into the tubes for strength.
> |> This is a very complex analysis that the magazines arent talking
> |> of anymore ! THEY DID 12-14 yrs ago !
>
> I wonder if this is because bikes aren't lugged anymore?
>
>
> |> Low cycle fatigue is not a big problem , im sure some would like
> |> to label all ruptures as low cycle for they're own reasons . It's
> |> only higher freq fatigue cycles that causes much shorter life than normal.
> |> In fact bikes suffer very low levels. It's simply pushing the frame
> |> close to the upper end of it's elastic region , not operating it at
> |> lower elastic levels and much more cycles.
>
> What in the hell are you talking about?
>
> Cycle frequency usually doesn't matter at typical
> riding temps/conditions. Elevated temperatures
> or highly corrosive enviroments are usually present
> before the loading frequency becomes a factor.
altavoz: You're confused . Corrosion/heat has nothing to do
with FATIGUE FAILURE !! Fatigue analysis is conducted at room
temp and no corrosion , no electrolysis, no change in freq.
> |> That is FATIGUE FAILURE , lower stress at millions of cycles rather
> |> than higher stress at the upper end of the proportional limit ( elastic
> |> limit ) at fewer cycles .
>
>
>
> |> Example, steel at 20 hz , at 10kips might fail at several million cycles
> |> and your steel bike would fail at .001 hz at 50kips in 1000
> |> "back and forth" bendings, the later should not be considered fatigue
> |> failure , but a UTS ( ultimate tensile strength) failure. just as .0001
> |> hz at 55kips at *1 back and forth bending s/b considered a UTS failure .
> |> The cycles a bike frame suffer are not 20 hz nor 100 hz nor 10000 hz
> |> and this is required for a fatigue failure. Otherwise it's just a UTS
> |> ( or Yield failure...u cant ride it if it's bent).
>
> No,thats incorrect.
>
> 1000 Loadings is a low-cycle fatigue failure.
> 1 loading is a tensile test.
altavoz: i stated above that in low cycle , varying load ( on a bike)
you're likely to yield rather than Fatigue . You will notice
the asterisk "i back and forthg bending.." but you cant follow that.
We all know that 1 flex below prop limit will not cause failure.
We also dont have NDT and Fatigue labs in our back yard. So we
cant assume that a frame failure was due to fatigue when we know the
probability that it was driven into the plastic region and failed
thru simple yield .
> Your definition of "fatigue failure" is completely
> unlike any I have ever heard.
>
> Then again, since you aren't a mechanical engineer,
> you probably can't be held responsible for much.
> Load frequency doesn't enter into defining high-cycle
> or low-cycle. Its based on number of cycles (or reversals),
> and load levels.
>
>
> When your work on fatigue is published and stands up to
> peer review, I'll believe your bullshit. Until then....
>
--
Kristan Roberge
altavoz <alt...@worldnet.att.net> wrote:
>
> Joshua_Putnam wrote:
> > Hype has been part of bicycle marketing since bicycles were
> > invented.
> altavoz : UR FULL OF SHIT .
that he may be, but at least he's not a Git like you.
> Back then , butted down tubes were shot down and immediately
> frame builders switched to plain gage . But today no one even
> cares !! We're back to butted down tubes . You're not into
> engineering , ur into arguing and hype.
When did 'butted down tubes' get shot down? I have a Gitane Professional
frameset, circa 1968-72 with a FULL Double-Butted Reynolds 531 tubeset.
Reynolds invented butted tubing a hundred years ago and I'm pretty sure
they've offered it on all the main tubes (except the BB shell and head
tube) since Day 1.
Your not into providing proof, your just into insulting, swearing,
and flaming, which your not very good at either! Take it from me,
I'm an expert (that note added for the benefit of mr. Helfrich).
Kristan Roberge
Gary Helfrich <lap...@wco.com> wrote:
> altavoz <alt...@worldnet.att.net> wrote:
>
> : altavoz: Thats nonsense , bikes are hype today . the frames
> : dont break cause they're light weight , they break cause of
> : poor engineering.* I will restate my oppinion that approx'
> Cool, another person who feels that bicycle magazines are a valid source
> of technical information.
I hate myself for this, but I'm agreeing with Gary... For those who haven't
paid attention, Altavoz is the latest "I'm an engineer so that means
I'm an expert on bikes" applicant to the newsgroup. So far his batting
average for useful contributions is below .100. His batting average
on insulting people is running around .950, much higher than mine in
fact.
> : * I even saw a steel frame with individual beads ( tig) like
> : you must do on alum' cause you'll plate the tungsten if you
> : dont puddle then pull it away and add the filler rod . ha ha
> : Maybe the idiot figured "if they do it on alum' ,it's good
> : for steel too"
>
> Did your parents give you that stupid name, altavoz, or is your real one
> too much of an embarasment to mention in public? Anonymous posters seem
> to require a good set of hip waders these days.
He has at times claimed to be an electrical engineer who also dabbles
in mechanical stress analysis (which obviously makes him qualified to
pick up a Tig welder and build a frame that will never fail).
> Have you ever welded anything? Do you even know how to turn a welding
> machine on? OK, how about a light bulb?
He's claimed to be an EE, so one assumes that means he knows how to
turn on a light bulb. Whether he knows how to unscrew a lightbulb
is another question.
> If you are going to rant and rave, start backing up your statements with
> some facts. This "I saw" or "I read it in a magazine" shit is just that.
Now I really hate myself for agreeing with you... hey, I bet he's
a technical consultant for MBA...
> I think that it is time for my medication.
And after reading this posting your likely going to want to check to
make sure you took the right medication.
altavoz
Joshua_Putnam wrote:
>
> In <53v4kp$a...@ns2.ryerson.ca> k...@acs.ryerson.ca (Kenly Uy - MHNG/W94) writes:
>
> >The point is, if bikes need to be of aero-grade
> >metals to be durable, why the hell did we not get catastrophic numbers of
> >failures with steel bikes?
>
> chromoly and Reynolds 531, for example.
>
> >What's the use of aero alloys if they're machined so thin such that their
> >best structural strengths are negated? To say that bikes exceed fighter
> >planes in performance is simply ridiculous.
>
> Nobody said anything about "performance," but rather stresses.
> It's quite clear that steel bicycles, which are made from
> aircraft alloys, suffer from fatigue failures significantly more
> often than airframes do. That's pretty clear indication that
> they are under higher stress, isn't it?
>
> Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
> "My other bike is a car."
> Used & classic bike parts for sale: finger Joshua...@WolfeNet.com for list.
My point is that these failures may not be FATIGUE FAILURES !! They
may be yield failures . and you'll spin your wheels trying to prove
they're fatigue failures !!
Kristan Roberge
altavoz <alt...@worldnet.att.net> wrote:
>
> Gary Helfrich wrote:
> > Have you ever welded anything? Do you even know how to turn a welding
> > machine on? OK, how about a light bulb?
> altavoz : Sorry to do this to you . Yes I tig weld and no one
> said anything about the tung' touching the work . Got ur foot
> out of ur mouth yet ? LOOK CAREFULLY YOU"LL FIND NO POST THAT
> SAYS ANYTHING ABOUT TOUCHING THE ELECTRODE TO THE WORK . DUMB SHIT.
Well, while I agree that gary does stick his foot in his mouth
occasionally, and while my general opionion of him involves the word
"shit",it doesn't however involve the word "dumb".
> One of my skills is elecrical engineering and i could design, and use
> any type of welder. I am also a airframe specialist . I also like
> structural mechanics ( wanna compete ? ).
Let's see... he's the poster-boy (and not for his looks) of the Titanium
bike industry, one of 3 co-founders of Merlin Metalworks, teachs framewelding
at the United Bicycle Institute, has likely by this time been inducted
into the Bicycle Hall of Fame (at least I'd hope so... lord knows his
ego doesn't need anymore boosting by getting inducted now or in the
future) for his contributions to the bike industry. He also gets invited
on alot of tours of the big Ti mills/suppliers and supposedly his backyard
is filled with piles of Ti and Steel and Aluminum tubing (lucky sod!).
I think he's qualified to match wits with you. He's certainly OVER-qualified
to insult your lack of intelligence. Kinda takes the sport out of it.
Kristan Roberge
altavoz <alt...@worldnet.att.net> wrote:
> > Designing for finite life is perfectly valid.
> > I don't read the magazines, but the *good* designers
> > I have spoken with do know what is going on.
>
> altavoz: then why dont you let them talk and you shut up.
Ok, let's get Keith Bontrager (who posts to this newsgroup fairly often),
Scott Nicol (who has been seen occasionally), and Gary Helfrich to
say a few words... But no wait, Keith already tells it like it is...
but the ONLY bike magazine that wants to print the truth as Keith tells
it and doesn't care about offending advertisers is a british mag
called MTB-Pro or MTB-UK. Gary does all his publishing in this
newsgroup and off-road occassionally, plus the odd magazine interview
every couple years. Scott Nicol runs his articles in velonews as I recall.
> > Aerospace parts are finite life. They don't break because
> > they are pulled out of service well before they are expected
> > to fail (hopefully).
Not in canada. Here we keep things flying until they become 10,000
individual parts flying in close formation...
> altavoz :ALL ALUM WELDERS KNOW HOW TO PUDDLE ALUM' THEN FEED THE FILLER ROD !!
Why save time and money welding aluminum when you can braze it... you
did know that you can braze aluminum right?!?
> > I have never heard of "plating the tugsten" and I have been
> > TIG welding for 3 years.
> altavoz : Maybe you need 20 or 30 years more.
Nope, your never supposed to plate or touch the tungsten to anything,
your supposed to let the electric current JUMP from the electrode
to the frame/tubing (like crossing the gap on a spark-plug).
> but most who weld alum will notice that if they get the filler
> rod too close to the Tung' they will find the tung' is plated with
> alum crap that must be removed . That is why all alum welding is
> discontinous , small beads. Steel does not require this technique.
> altavoz: as long as you hype us , i'll be here .
> ALUMINUM AND CARBON FIBER ARE NOT GOOD BIKE FRAME MATERIALS.
Batshit... Both are GREAT bike frame materials if you know how to
design for their limitations.
> "V" brakes are crap ! They still havent figured out MTN bike brakes,
Actually I have, so has Jobst brandt, Keith Bontrager, and Sheldon Brown.
The myth of V-brakes is that they offer more powerful braking that what
is possible with regular cantilevers. Alas if you fell for the shimano
hype that you needed a low-leverage, long-pull lever you'd also be
a victim of the myth. High leverage brakes don't neccessarily need more
cable pull, but instead need people to be educated that a soft lever
feel equates to more power than a firm lever feel. Lowering the lever's
mechanical advantage and increasing the cable pull allowed shimano to
avoid (A) lawsuits from people who launched over their handlebars
when reaching for a handful of front brake and (B) give the morons of
the world that FIRM brake lever feel that means more powerful brakes.
> cant's are crap ! Most expensive pedals have shitty bearings.
Most do, some don't,
> TELESCOPIC SHOCKS ARE WRONG ! Stop copying motorcycles !!
They are NOT wrong if you want MORE travel than is possible with a linkage
or leading/trailing axle-design. The only way to get more travel out of
a linkage fork without a major redesign in frame geometry in to use a
smaller diameter front wheel.
> Motorcycles went to inverted tubes and forgot why they did that !
Nope, they went to inverted forks to put more material in the spot
where most of the stress was concentrated (the upper legs) while keeping
the weight of the forks the same.
> ( to get rid of the triple clamps and make it one piece Magnesium )
The magnesium alloys used in bike and motorcycle parts today are
NOT an ideal material. let's see.... roughly the same strength as
aluminum, and half the weight, but ALSO half the stiffness... hmmmm...
and people wonder why I laugh at magnesium fork braces.
> You cant use a 12-xx freewheel ! It'll lose races thru friction !!
So you lose a little in the friction... you also gain alot in the gearing
department.
> Too few teeth on the chain !! Campy BB bearings are inferior to the
> low cost cart' bearings made by SKF !!
Campy's ball-bearings are some of the NICEST made in the world, always
have been and likely always will be. SKF is one of the best sealed
cartridge bearing makers in the world though. But comparing cartridge
bearings to regular ball-bearings isn't exactly fair.
Dana Rottach
Mike Davis (mda...@futurenet.co.uk) wrote:
>In article <PATMILLS.1...@SCIENCE2.watstar.uwaterloo.ca>,
>PATM...@SCIENCE2.watstar.uwaterloo.ca (Peter Mills) wrote:
>> lived with a room mate who owned a 'Dale. Behind the seat tube there was a
>> notice instructing the owner of the bicycle to inspect it regularly for
>> frame fatique, particularly under the down tube. If Cannondale knows that
>> these failures are occurring, why don't they do something about it, like
>> make their bikes stronger? Instead, they put some lame sticker on the
>
>I think you'll find that a lot of alu bikes have these stickers in the
>States. The CPSC make manufacturers put them there, like the _really_ lame
>one about doing up the QRs properly. Besides, inspecting the frame
>regularly for cracks or other damage is good practice whatever the frame
>is or what it's made of...
If the repeated loading of a steel part is less than about half of what it
would take to immediately break the part, it has an effectively infinite
fatigue life. The 45 year-old bike I tool around on isn't about to
self-destruct.
Aluminum, however, has no such proportion. No matter how overbuilt the
bike is, it will fatigue with use, and eventually fail. I'm still not
too greatly concerned about my eight year-old Cannondale, but I do look
at the joints every once in a while.
--
Dana!
Kristan Roberge
k...@acs.ryerson.ca (Kenly Uy - MHNG/W94) wrote:
>
> Jim Papadopoulos (bicyc...@delphi.com) wrote:
> : Kenly Uy - MHNG/W94 <k...@acs.ryerson.ca> writes:
> :
> : >Bikes go nowhere near the stresses of flying planes, but give you a
> :
> : What can you mean by this? Some bikes use high
> : strength "aerospace" alloys, and also break. So the stresses
> : had to be pretty high! probably GREATER than in a
> : well designed airplane.....
> :
> : Jim
>
>
> Oh, yeah, I forgot that high-performance bikes go to 9G acclerations.
>
> Please give me a case where a bike has undergone greater stresses than a
> failures with steel bikes?
More specifically, why do some people still ride the Kamikaze downhill
every summer on 1020 Hi-tensile steel framed Huffy's and survive while
people riding frames made out of Titanium end up walking down after
their frame failed halfway up the hill?!?
> What's the use of aero alloys if they're machined so thin such that their
> best structural strengths are negated? To say that bikes exceed fighter
> planes in performance is simply ridiculous.
What good is it for the fighter plane to withstand 15Gs if your brain
turns to go at 12G?!?
c m lozier
In <mdavis-1710...@172.18.22.102> mda...@futurenet.co.uk (Mike
Davis) writes:
>
>In article <PATMILLS.1...@SCIENCE2.watstar.uwaterloo.ca>,
>PATM...@SCIENCE2.watstar.uwaterloo.ca (Peter Mills) wrote:
>
should
>> have a lifetime warranty. I would never by a Cannondale. Why?
Recently I
there was a
>> notice instructing the owner of the bicycle to inspect it regularly
for
>> frame fatique, particularly under the down tube. If Cannondale
knows that
>> these failures are occurring, why don't they do something about it,
like
>> make their bikes stronger? Instead, they put some lame sticker on
the
the most
>> inaccessible location possible. This was even a hybrid, a type of
bike
>> which should be designed for utilitarian use, not high performance
riding.
>
>States. The CPSC make manufacturers put them there, like the _really_
lame
>one about doing up the QRs properly. Besides, inspecting the frame
>regularly for cracks or other damage is good practice whatever the
frame
>is or what it's made of...
>
Mike Davis,
I've owned two C'dales and I will tell you they are if not the best,
then they are among the best. If you looked at alum bikes in the usa,
you'd find they all have that sticker. Mountain bikes can break when
ridden to extremes, c'dale has an outstanding warranty on it's bikes.
Please don't knock the product simply because it has a sticker on it
like all other alum bikes in the usa. That's really foolish.
Kristan Roberge
altavoz <alt...@worldnet.att.net> wrote:
> The Heated debate would subside if more would study eng' or go
Alas it would also subside if you weren't such a complete smeghead.
Gary helfrich ( I believe you called him a 'dumb shit') has studied
engineering, teachs bicycle frame building and specifically Ti frame
welding at the United Bicycle Institute, and has been manufacturing
Titanium bike frames for over a decade and steel frames for about two
decades. This makes him qualified enough for everyone else in this
newsgroup to answer technical questions, but apparently not enough for
you... a newbie to the group. a newbie who has earned more enemies in
such a record short-time than even Mike V.
Chris Fabri
>
> Mike Davis,
> I've owned two C'dales and I will tell you they are if not the best,
> then they are among the best. If you looked at alum bikes in the usa,
> you'd find they all have that sticker. Mountain bikes can break when
> ridden to extremes, c'dale has an outstanding warranty on it's bikes.
> Please don't knock the product simply because it has a sticker on it
> like all other alum bikes in the usa. That's really foolish.
At least direct your comment at the right person. Mike was not the one
"knocking" Cannondales. The comment I believe you were referring to was
from Peter Mills.
> In article <PATMILLS.1...@SCIENCE2.watstar.uwaterloo.ca>,
> PATM...@SCIENCE2.watstar.uwaterloo.ca (Peter Mills) wrote:
> > I don't think I'm alone in believing that all good bicycle frames should
> > have a lifetime warranty. I would never by a Cannondale. Why? Recently I
> > lived with a room mate who owned a 'Dale. Behind the seat tube there was a
> > notice instructing the owner of the bicycle to inspect it regularly for
> > frame fatique, particularly under the down tube. If Cannondale knows that
> > these failures are occurring, why don't they do something about it, like
> > make their bikes stronger? Instead, they put some lame sticker on the
> > frame, and try to hide it from a potential buyer by placing it in the most
> > inaccessible location possible. This was even a hybrid, a type of bike
> > which should be designed for utilitarian use, not high performance riding.
> >
> > Peter Mills
> >
> I think you'll find that a lot of alu bikes have these stickers in the
> States. The CPSC make manufacturers put them there, like the _really_ lame
> one about doing up the QRs properly. Besides, inspecting the frame
> regularly for cracks or other damage is good practice whatever the frame
> is or what it's made of...
>
> Later,
>
> Mike.
>
> --
> Mike Davis
> mda...@futurenet.co.uk
> http://www.futurenet.co.uk/
Chris Fabri
fab...@nwu.edu The computer erased my old sig.
c m lozier
In <fabric-1710...@he-man.nsg.nwu.edu> fab...@nwu.edu (Chris
Chill out... What's your point anyway, so what if a continuation of a
thread is incorrectly addressed.
Kristan Roberge
Mark Hickey <mhi...@cynetfl.com> wrote:
>
> k...@acs.ryerson.ca (Kenly Uy - MHNG/W94) writes:
>
> > Oh, yeah, I forgot that high-performance bikes go to 9G acclerations.
> >
> > Please give me a case where a bike has undergone greater stresses than a
> > well-designed airplane.
>
> THEN undergo 9G's and I'll be impressed.
Good point. Typical Ti frame is about 3.5 Ibs. Now I'm not sure home
much Gary Helfrich weighs, but given the stories I've heard (like
how his friends used to send him out on the lake in the winter to test
the thickness of the ice) I'd say he's over the 200 Ibs mark. So
200 / 3.5 = 57.14 ...Hmmmm... now that's a pretty good ratio compared
to an airplane where the useful load : aircraft weight is LUCKY to be
1:1. Now I don't know about 9G loads, but 6G is well within the range
of normal offroad riding. Still, generally only unlimited aerobatic
and military aircraft are designed for continuous loading over 6G...
Hans-Joachim Zierke
Jobst Brandt schrieb am 16.10.96:
> Yes, that's like books titled: "The Complete Book on Modern Bicycles",
> titles that could as well have come from the last century as the next.
> Often, thinking MY era is the acme of something or other, is naive.
An example that I love, are people, who complain about the press, and say
that all those believers into journalists without knowledge is a sign of
our bad modern times.
My answer to this has been since years:
DIREKTOR. Ein solcher Vorwurf läßt mich ungekränkt:
Ein Mann, der recht zu wirken denkt,
Muß auf das beste Werkzeug halten.
Bedenkt, Ihr habet weiches Holz zu spalten
Und seht nur hin, für wen Ihr schreibt!
Wenn diesen Langeweile treibt,
Kommt jener satt vom übertischten Mahle,
Und was das allerschlimmste bleibt,
Gar mancher kommt vom Lesen der Journale.
This is out of "Vorspiel auf dem Theater", Johann Wolfgang Goethe: Faust.
If I remember right, "Faust" was published between 1800 and 1810. Therefore
we see, that complaints about press quality and believers into what was
written, were most likely rather common in the Weimar of 1800.
hajo
P.S.: No, Jobst, this time I'm NOT going to translate. My English might be
enough to translate bicycle books (somehow), but certainly isn't for
poetry.
altavoz
Camiel Rouweler wrote:
>
> altavoz <alt...@worldnet.att.net> wrote:
>
> >Alum' is used cause as you thin a tube to make it strong( moment
> >of inertia) the wall gets so thin on steel ,you could push
> >a pin thru it. Ratio of MOM of INERTIA to it's wall thickness.
>
> intertia from what I have, or this is just complete BS. What would
> one care what the moment of inertia of a tube is? They sure aren't
> rotating when I ride my bike.
>
altavoz" same wt per foot, bigger dia to increase Mom of inertia,
means thinner wall.
> --
> Camiel Rouweler (cami...@surf.phys.tue.nl)
altavoz: Mom of Inertia "Io" is a measure of stiffness ( page
120 machinery handbook 24 th ed) or how much material is far
from the nuetral bend axis. An I beam has all the material
pushed as far as possible from the nut bend axis and has a very
high Io . The web is minimum . It isnt even considered in the
I beam strength unless your ratio of depth to length is < 10:1
approx , cause thats where shear starts to dominate over bend
Moment ( not same as Moment of inertia..notice that there are
MANY MOMENTS !) . As you make the I beam very short , the web is
the only important member ! The compression flange must be braced
every 9" on a 6" I beam ( 150%) cause it will fold up ( the tension
flange is not a problem.
The books say "proportional limit" alias "2% offset" alias "Modulus
of elasticity"...we use Prop limit. Its the load divided by
deflection . Steel has 29 million PSI( heat treated is only slight higher)
and 1 " cube will stretch to 2" at 29 million lbs, but this slope is
LIMITED ( it will fail long before this point). So we use 1/1000 the
load ( 29,000 PSI ) and expect stretch of .001" . since hot rolled
steel yields( permanent bend) at 36000 PSI , you'll only pull
this cube a little more than .001" .
FATIGUE FAILURES occur below this 36000 PSI . You cant subject your
frame to 120 bounces around the race track and one of those bounces bends
the frame , and blame it on FATIGUE , cause your failure went into the
plastic range ( above the Prop' limit).
Henrik Münster
I've always heard, that a tube (hollow) is stiffer than a rod
(solid) of the same outside diameter and material, and the bigger the
bore the stiffer the tube. That must mean, that thinner walls makes
stiffer tubes.
Regards
Henrik
Paul <pa...@discordia.org> wrote (écrivait) :
> In article <5455t8$o...@tuegate.tue.nl>, Camiel Rouweler
> <cami...@surf.phys.tue.nl> wrote:
>
> > altavoz <alt...@worldnet.att.net> wrote:
> >
> > >Alum' is used cause as you thin a tube to make it strong( moment
> > >of inertia) the wall gets so thin on steel ,you could push
> > >a pin thru it. Ratio of MOM of INERTIA to it's wall thickness.
>
> > I also never heard of making tubes _stronger_ by making them thinner.
>
> A lot of frame maker make the frame stiffer by making the tubes
> larger. To maintain the weight, they make the tube thinner.
> With a low density material like aluminum, you can get a decent
> thickness and still maintain the weight. A higher density material
> like steel would have to be thinner to maintain the same weight.
> The thinner walls would be suspectible to crushing like a beer can.
> Not quite thinner = stronger, but perhaps that's what the other
> poster meant.
>
> Don't know what MOM or INERTIA is or have to do with frames.
>
> Paul
> pa...@discordia.org
altavoz
Matt Bushore wrote:
> What in the hell are you talking about?
>
> Cycle frequency usually doesn't matter at typical
> riding temps/conditions. Elevated temperatures
> or highly corrosive enviroments are usually present
> before the loading frequency becomes a factor.
>
> |> than higher stress at the upper end of the proportional limit ( elastic
> |> limit ) at fewer cycles .
>
>
>
> |> Example, steel at 20 hz , at 10kips might fail at several million cycles
> |> and your steel bike would fail at .001 hz at 50kips in 1000
> |> "back and forth" bendings, the later should not be considered fatigue
> |> failure , but a UTS ( ultimate tensile strength) failure. just as .0001
> |> The cycles a bike frame suffer are not 20 hz nor 100 hz nor 10000 hz
> |> and this is required for a fatigue failure. Otherwise it's just a UTS
> |> ( or Yield failure...u cant ride it if it's bent).
>
> No,thats incorrect.
>
> 1000 Loadings is a low-cycle fatigue failure.
> 1 loading is a tensile test.
>
> unlike any I have ever heard.
>
> Then again, since you aren't a mechanical engineer,
> you probably can't be held responsible for much.
>
> Load frequency doesn't enter into defining high-cycle
> or low-cycle. Its based on number of cycles (or reversals),
> and load levels.
>
>
> When your work on fatigue is published and stands up to
> peer review, I'll believe your bullshit. Until then....
altavoz: ooooooppppsss i hit the send button prematurely.
Lets take a vote on who is BS and who isnt ! What have you offerd
this news group ? Everybody bomb the guys mail box who you think
isnt contributing to this NG !
Robert Horvatich
Peter Mills wrote:
> I don't think I'm alone in believing that all good bicycle frames should
> have a lifetime warranty. I would never by a Cannondale. Why? Recently I
> lived with a room mate who owned a 'Dale. Behind the seat tube there was a
> notice instructing the owner of the bicycle to inspect it regularly for
> frame fatique, particularly under the down tube. If Cannondale knows that
> these failures are occurring, why don't they do something about it, like
> make their bikes stronger? Instead, they put some lame sticker on the
> frame, and try to hide it from a potential buyer by placing it in the most
> inaccessible location possible. This was even a hybrid, a type of bike
> which should be designed for utilitarian use, not high performance riding.
I have seen a very similar sticker on a GT as well. Does that mean GT
is out to get us by trying to inform their customers? Is Cannondale
cheating us by informing us on how to inspect our frames? So now
their is a conspiracy theory since the sticker is not smack dab
in the middle of the down tube where it can be seen by everyone and
impact the appearance of the bike.
FYI, the low end hybrid you speak about that has Cannondale written on
the side DOES have a life time warranty. It is only the high end bikes
in Cannondale's lineup that has the limited 5 year warranty.
It is not only Cannondale that knows where bikes typically fail but just
about any other knowledgable frame builder. Take a look at the FAQ
or just read some peoples experience with failures here on the group.
I don't think Cannondale is hiding anything. Think about it for
just one moment. If Cannondale wanted to hide something, why would
they put a sticker on their bikes. Maybe it is the other manufacturers
that are hiding something?
Rob
> Peter Mills
--
email: |"You can't take life too seriously,
rhor...@ae0119.pd8.ford.com | you don't get out alive." Buggs Bunny
Chris Fabri
The computer erased my old sig.
>
> Chris Fabry:
> Chill out... What's your point anyway, so what if a continuation of a
> thread is incorrectly addressed.
It would be nice if you would be this considerate in your personal replies.
It would also be nice if you would spell my name right.
If you're going to be critical about something, it's nice to at least be
critical of the right person. I was simply pointing this out. No flames
intented.
It *is* alright to admit your mistakes. chris.
Gary Helfrich
altavoz <alt...@worldnet.att.net> wrote:
: altavoz : Sorry to do this to you . Yes I tig weld and no one
: said anything about the tung' touching the work . Got ur foot
: out of ur mouth yet ? LOOK CAREFULLY YOU"LL FIND NO POST THAT
: SAYS ANYTHING ABOUT TOUCHING THE ELECTRODE TO THE WORK . DUMB SHIT.
:
I believe that Ur was an ancient city in the Mid east. I have a big mouth
but fitting an entire city in it seems unlikely. Even only one foot in
would be tough.
Why should any one believe that your claim that you tig weld is true?
Hiding behind a pseudonym does little for your credibility. Judging by
your writing style (I am using style in a very loose sense here) I'd say
that you are either Mike Vandeman or Dr. Bronner.
: One of my skills is elecrical engineering and i could design, and use
: any type of welder. I am also a airframe specialist . I also like
: structural mechanics ( wanna compete ? ).
One would think that if electrical engineering is your field, you would be
able to spell electrical. What does electrical engineering have to do with
the ability to weld? Are you sure that you don't have a short somewhere?
I was not aware that structural mechanics was an athletic event. I'm not
that hot at sports, but this is a new one. Or were you referring to that
cute daughter that Mr. and Mrs. Mechanics have? You can have her, little
Structural is a bit young for me. No need to compete.
Why should anyone believe that you are any of these things? An airframe
specialist? Ok, who do you work for? Give it up and beam yourself back
up.
: Now watch this idiot , i've proven him wrong but it wont fase him
: a bit , he'll pretend like he wasnt wrong ...BILL CLINTON
: ______End of text from altavoz___________
Unlike Bill, I inhaled, and I liked it. What have you proved, besides
demonstrating your limited command of the English language? If you are
too much of a twerp to sign your posts with your real name, why should any
one believe anything else that you state?
Gary Helfrich
Arctos Machine
Mike
altavoz wrote:
: altavoz: Mom of Inertia "Io" is a measure of stiffness ( page
: 120 machinery handbook 24 th ed) or how much material is far
: from the nuetral bend axis. An I beam has all the material
: pushed as far as possible from the nut bend axis and has a very
: high Io . The web is minimum . It isnt even considered in the
: I beam strength unless your ratio of depth to length is < 10:1
: approx , cause thats where shear starts to dominate over bend
: Moment ( not same as Moment of inertia..notice that there are
: MANY MOMENTS !) . As you make the I beam very short , the web is
: the only important member ! The compression flange must be braced
: every 9" on a 6" I beam ( 150%) cause it will fold up ( the tension
: flange is not a problem.
: The books say "proportional limit" alias "2% offset" alias "Modulus
: of elasticity"...we use Prop limit. Its the load divided by
: deflection . Steel has 29 million PSI( heat treated is only slight higher)
: and 1 " cube will stretch to 2" at 29 million lbs, but this slope is
: LIMITED ( it will fail long before this point). So we use 1/1000 the
: load ( 29,000 PSI ) and expect stretch of .001" . since hot rolled
: steel yields( permanent bend) at 36000 PSI , you'll only pull
: this cube a little more than .001" .
: FATIGUE FAILURES occur below this 36000 PSI . You cant subject your
: frame to 120 bounces around the race track and one of those bounces bends
: the frame , and blame it on FATIGUE , cause your failure went into the
: plastic range ( above the Prop' limit).
: ______End of text from altavoz___________
Uh oh...
Maybe this EE should stick to wiring toasters.
Mike Johnson - CSM Dept of Metallurgical and Materials Eng - Golden CO
Matt Bushore
In article <32666B...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
|> Matt Bushore wrote:
|> >
|> > In article <326486...@worldnet.att.net>, altavoz <alt...@worldnet.att.net> writes:
|> > |> Jim Papadopoulos wrote:
|> > |> >
|> > |> > altavoz <alt...@worldnet.att.net> writes:
|> > |> >
|> > |> > >poor engineering.* I will restate my oppinion that approx'
|> > |> > >12 years ago we made a sudden direction change toward HYPE.
|> > |> > >Prior to that , any one trying to smoke screen the public
|> > |> > >would quickly get hammered by the excellent magazine articles
|> > |> > >that showed the truth.
|> > |> > >
|> > |> >
|> > |> > Every bike part I've broken (in normal riding) was from that
|> > |> > era. What do you know about low cycle fatigue, anyway?
|> > |> > Jim P.
|> > |>
|> > |> Low cycle fatigue is not a big problem , im sure some would like
|> > |> to label all ruptures as low cycle for they're own reasons . It's
|> > |> only higher freq fatigue cycles that causes much shorter life than normal.
|> > |> In fact bikes suffer very low levels. It's simply pushing the frame
|> > |> close to the upper end of it's elastic region , not operating it at
|> > |> lower elastic levels and much more cycles.
|> >
|> > What in the hell are you talking about?
|> >
|> > Cycle frequency usually doesn't matter at typical
|> > riding temps/conditions. Elevated temperatures
|> > or highly corrosive enviroments are usually present
|> > before the loading frequency becomes a factor.
|>
|> altavoz: You're confused . Corrosion/heat has nothing to do
|> with FATIGUE FAILURE !! Fatigue analysis is conducted at room
|> temp and no corrosion , no electrolysis, no change in freq.
Let me help you out here, or you can help me out. We'll see.
I've built clamps to hold silicone heaters to coupons.
The heaters were used to elevated the temperature of the
test material to the expected use temperature. The samples
were of a heat treated Titanium alloy being considered for
use in the National Space Plane.
You are asserting that the testing was actually a fatigue test?
What was it then?
How am I going to tell this to my friends that do fatigue testing?
How can I tell my prof that his book is all wrong?
|> > |> That is FATIGUE FAILURE , lower stress at millions of cycles rather
|> > |> than higher stress at the upper end of the proportional limit ( elastic
|> > |> limit ) at fewer cycles .
|> >
|> >
|> >
|> > |> Example, steel at 20 hz , at 10kips might fail at several million cycles
|> > |> and your steel bike would fail at .001 hz at 50kips in 1000
|> > |> "back and forth" bendings, the later should not be considered fatigue
|> > |> failure , but a UTS ( ultimate tensile strength) failure. just as .0001
|> > |> hz at 55kips at *1 back and forth bending s/b considered a UTS failure .
|> > |> The cycles a bike frame suffer are not 20 hz nor 100 hz nor 10000 hz
|> > |> and this is required for a fatigue failure. Otherwise it's just a UTS
|> > |> ( or Yield failure...u cant ride it if it's bent).
|> >
|> > No,thats incorrect.
|> >
|> > 1000 Loadings is a low-cycle fatigue failure.
|> > 1 loading is a tensile test.
|>
|> altavoz: i stated above that in low cycle , varying load ( on a bike)
|> you're likely to yield rather than Fatigue . You will notice
|> the asterisk "i back and forthg bending.." but you cant follow that.
|> We all know that 1 flex below prop limit will not cause failure.
|> We also dont have NDT and Fatigue labs in our back yard. So we
|> cant assume that a frame failure was due to fatigue when we know the
|> probability that it was driven into the plastic region and failed
|> thru simple yield .
One cycle (your "i back and forthg bending.." ) is not
a UTS. Ultimate tensile tests, by definition, are conducted
by loading in one direction only.
I'm not sure why you continue to agrue mechanics of materials
with mechanical engineers. If it makes you feel better, you
are amusing a lot of Master's degree students.
Let me ask you these questions:
A bicycle is ridden for 1 year. During the spring,
the owner inspects it and finds a small crack forming
on the underside of the aluminum fork crown where the
steerer tube is pressed into the aluminum.
The crack is propagating from the pressed insert towards
a lightening hole drilled in the bottom side.
(This is how my Rock Shox Mag 20 forks failed)
How did the crack get there?
When will the fork fail?
Will the crack grow faster if the bike is ridden on salty roads
or dirts trails?
Will the failure mode be brittle or ductile?
Hint: You can't answer all of these, but I think they
are very instructive points to consider.
(the above questions might actually be of some interest for
discussion? too bad they are part of this thread..)
Mike
Mike wrote:
: Uh oh...
: Maybe this EE should stick to wiring toasters.
: Mike Johnson - CSM Dept of Metallurgical and Materials Eng - Golden CO
Mike also meant to add:
I'm afraid Mr altavoz (isn't that spanish for "high voice"?) needs to
bone up on his definitions a bit more before spewing forth. Thank goodness
there are people out there who actually understand how to use material
property data.
____________________________________________________________________________
Mike Johnson - CSM Dept of Metallurgical and Materials Eng - Golden CO
Strip mining prevents forest fires. Support the resource industries.
----------------------------------------------------------------------------
nbce...@delphi.com
Przemyslaw Siedzinski <big...@aurora.put.poznan.pl> writes:
>Do you ride one bike longer then 5 years ??? It must be pretty dull :)
>I don't think there are frames that can't be break so maybe cannondale's
>sticker is ... well honest ?
Been riding my Austro Daimler Ultima (after switching out the titanium bb)
since 1979. Let me know how your pop can is doing a age 15 or so.
Brian Lafferty
David Blake
altavoz wrote:
...
> altavoz: ooooooppppsss i hit the send button prematurely.
> Lets take a vote on who is BS and who isnt ! What have you offerd
> this news group ? Everybody bomb the guys mail box who you think
> isnt contributing to this NG !
>
I hereby nominate altavoz for Kook of the Month.
Followups to alt.usenet.kooks
--
Dave Blake
dbl...@phy.ucsf.edu
http://www.keck.ucsf.edu/~dblake
altavoz
Kristan Roberge wrote:
>
> altavoz <alt...@worldnet.att.net> wrote:
> >
> NAME THEM YOU GIT!
> altavoz : GO TO HELL , GIT! ....MORON
altavoz
> > after welding ( w/o heat treatment) . GO TO SCHOOL ,
> > GET SOME EXPERIENCE !
>
> BULL FUCKING SHIT. CrMo does NOT need to be heat-treated to have strength
> after welding, nor does Titanium, nor does Beryllium or Albemet, or
> Aermet 100, nor 7005 aluminum (this at least naturally ages to a T4
> level within a couple months).
altavoz: Ha ha ha ha ha ha ha CrMo has strength after welding !!
ha ha ha ha ha ha h !!!!! Thats the dumbest thing I've ever heard !
The Cr just keeps it from oxidizing at very high temp , it adds
nothing to strength ! S.S. has 11% Cr .
Mo adds toughness ( still no strength increase) .
YOU IDIOT ITS THE CARBON THAT ADDS STRENGTH AND ONLY AFTER QUENCHING
AND YOUR FILLER ROD BETTER BE SLIGHTLY HIGHER CARBON CAUSE OF LOSS IN
WELDING.
You're the loudest, no nothing i've ever seen . Any minute a metalurgist
will happen by and shoot you down !
altavoz
> >
> > > Well, there's no major improvement over cantism I'd grant you. They're
> > > hardly 'crap'. They stop the bike. That's what counts.
> >
> > altavoz : No its not what counts, riders are complaining about
> > adjusting the power ( how hard they pull on lever). My brake
> > has adjustable power cause of "over center" . Do you need an
> > explain on over center ?
>
> The term is modulation (adjusting the power) you git, if your gonna
> talk about brakes get the terms right. I think we'll all get a nice
> chuckle out of your explaination of "over center". A term I've NEVER
> heard/read/seen applied to brakes... and I've been a bike mechanic for
> 10 years.
altavoz: WE INVENTED THESE TERMS BEFORE YOU WERE BORN , GIT.
POWER OR MECHANICAL LEVERAGE IS THE PROPER TERM , GIT , DS,
You , a bike mechanic ?!!?
IF YOU'VE NEVER HEARD OF OVER CENTER, YOU HAVE NO BUSINESS TALKING
ABOUT MECHANICAL THINGS DUMB SHIT.
altavoz
>
> > > Hype has been part of bicycle marketing since bicycles were
> > > invented.
>
> > altavoz : UR FULL OF SHIT .
>
> that he may be, but at least he's not a Git like you.
>
> > Back then , butted down tubes were shot down and immediately
> > frame builders switched to plain gage . But today no one even
> > cares !! We're back to butted down tubes . You're not into
> > engineering , ur into arguing and hype.
>
> When did 'butted down tubes' get shot down? I have a Gitane Professional
> frameset, circa 1968-72 with a FULL Double-Butted Reynolds 531 tubeset.
> Reynolds invented butted tubing a hundred years ago and I'm pretty sure
> they've offered it on all the main tubes (except the BB shell and head
> tube) since Day 1.
altavoz : Is your name Joseph McCarthy ? you use his tactics ! You idiot,
Gitane is proof of nothing , it's just one make !!! MORON
> Your not into providing proof, your just into insulting, swearing,
> and flaming, which your not very good at either! Take it from me,
> I'm an expert (that note added for the benefit of mr. Helfrich).
altavoz : The proof , you will pay for just as i had to pay for it.
so start searching Dumb Shit. ha ha ha ha you're an expert , everybody's
an expert . ha ha ha