Torsional stiffness, example Klein

On Apr 26, 2:35*am, Chalo wrote:
Andre Jute wrote:

Jimbo said of Klein that "they not only figured out the torsional
stiffness thing, but actually acted on it. *they deserve medals for
that."

Can you give us some references, preferably with pics, and maybe you
want to spin out a short par so we know to look for precisely what
you're referring to.

Gary Klein is often credited as being the first to offer a commercial
big-tube aluminum bike. *As far as I can tell, Harlan Meyers of Hi-E
beat him to it by a span of years, having brought his frame to market
in 1972, a year before Klein claims to have conceived the idea while
in college.

http://www.wooljersey.com/gallery/v/...osters/Hi-E/19...

Fat tubes are torsionally much stiffer than skinny ones. *This
accounts for the relative lack of BB sway in fat-tubed aluminum frames
versus traditional steel ones. *The problem "jim beam" has is in
believing it matters that much. *If one prefers the feel of a
torsionally stiff frame, a very fat-tubed and not-too-light aluminum
frame may be the most cost- and weight-effective way to attain that
end. *But many of us either don't care or prefer more springiness in
our frames.

Having become infatuated at one time with the superior stiffness of
big-tube aluminum frames, I now feel more or less agnostic on the
matter. *I believe that there is far more difference and more benefit
in a stiff crank and BB spindle, since using these has made various
otherwise inadequate skinny-tubed steel bike frames more than
acceptable for my own use.

Chalo

Thanks. Hindsight is such a wonderful thing: I got the big tubes, but
was expecting something *more* from the way Jumbo went on. But of
course, those big tubes weren't handed down from the finger of god;
they had to be scaled in the light of experience, and the processes
worked out.

Andre Jute
I'm not a know-all. I don't need to be. I know who to ask.

On 26 Apr, 15:49, jim beam wrote:

Steel bikes are
proven.

yeah! *proven heavy. *proven fatigue vulnerable.

I've thought about the frame failures I have seen. The failures of
top tube and main tube near to the head tube are, I believe to be due
to the builder not cutting an opening in the head tube to shoot the
top and main tube through. By leaving the headtube intact, the area
is too stiff in comparison to the top and main tube. This extra
stiffness is detrimental to the longevity of top and main tube because
it concentrates the bending loads to the end of the lug or butt.
Making the head tube joints a little less stiff will help to reduce
top and main tube failure. This is more relevant with small frames
(short stiff headtube).

Andre Jute wrote:
On Apr 26, 3:49�pm, jim beam wrote:
Chalo wrote:

why don't you and andre just **** off together and create homoerotic
"art"? �[you're an "artist" aren't you chalo?] �because all you're
doing, without any spark of originality or independent thinking [and
/definitely/ no attempt to educate yourself] is simply humping andre's
completely engineering-free bull****.

I'm always amused when some humourless techie thinks his minor
specialty gives him the right to tell other people what they can do
and say. Yo, Jumbo, I've done more engineering in my life than you
will ever do.

of course you have andre!!! you're a paid professional, not an amateur
hack!!!


Have you for instance built a 68ft long monocoque
structure out of any material? My City of Germiston, a yacht I
designed and built out of moulded wood and then raced on the most
dangerous oceans, is still serving as a weather ship. I subsumed
everything you know that is relevant to me before I finished my teens,
sonny.

this is the one where you dismissed the engineers that didn't agree with
you, right? because you're better than they? i'll bet you build space
shuttles as well.



And if I were in any doubt, I would ask the craftsman machining the
component for his opinion, not you. In short, I'd ask Chalo or his
local equivalent, not you.

poor andre's bent out of shape.



You're pretty unpleasant for a man with so little utility, Jumbo. You
should learn that the material is the least important element of any
artifact. What matters is the structure made with the material.

oh andre, if you only knew how ****ing bizarre that statement was!



Andre Jute
Not everything in materials is dreamt of in Timoshenko

and the guy that shovels coal into a steam loco's boiler is an "engineer".

Nick L Plate wrote:
On 26 Apr, 15:49, jim beam wrote:

Steel bikes are
proven.
yeah! �proven heavy. �proven fatigue vulnerable.

I've thought about the frame failures I have seen. The failures of
top tube and main tube near to the head tube are, I believe to be due
to the builder not cutting an opening in the head tube to shoot the
top and main tube through. By leaving the headtube intact, the area
is too stiff in comparison to the top and main tube. This extra
stiffness is detrimental to the longevity of top and main tube because
it concentrates the bending loads to the end of the lug or butt.
Making the head tube joints a little less stiff will help to reduce
top and main tube failure. This is more relevant with small frames
(short stiff headtube).

dude, you're barking up entirely the wrong tree as usual. "diamond"
frames are fundamentally flawed in the head tube location because it's
not a triangle, it's a trapezium. geometry and loading ensures it has
has the maximum degree of movement at this location. movement means
strain. strain means fatigue. if you want to mitigate the strain,
mitigate the movement. quite a few modern designs "trumpet" the top and
down tubes in this location for precisely this reason. others add
reinforcing places to increase stiffness.

either way, you need to understand engineering fundamentals. mitigate
the strain, you'll mitigate the fatigue.

Andre Jute wrote:
On Apr 26, 4:47�pm, Jay Beattie wrote:
On Apr 25, 6:35�pm, Chalo wrote:



Andre Jute wrote:
Jimbo said of Klein that "they not only figured out the torsional
stiffness thing, but actually acted on it. �they deserve medals for
that."
Can you give us some references, preferably with pics, and maybe you
want to spin out a short par so we know to look for precisely what
you're referring to.
Gary Klein is often credited as being the first to offer a commercial
big-tube aluminum bike. �As far as I can tell, Harlan Meyers of Hi-E
beat him to it by a span of years, having brought his frame to market
in 1972, a year before Klein claims to have conceived the idea while
in college.
http://www.wooljersey.com/gallery/v/...osters/Hi-E/19...
Fat tubes are torsionally much stiffer than skinny ones. �This
accounts for the relative lack of BB sway in fat-tubed aluminum frames
versus traditional steel ones. �The problem "jim beam" has is in
believing it matters that much. �If one prefers the feel of a
torsionally stiff frame, a very fat-tubed and not-too-light aluminum
frame may be the most cost- and weight-effective way to attain that
end. �But many of us either don't care or prefer more springiness in
our frames.
Having become infatuated at one time with the superior stiffness of
big-tube aluminum frames, I now feel more or less agnostic on the
matter. �I believe that there is far more difference and more benefit
in a stiff crank and BB spindle, since using these has made various
otherwise inadequate skinny-tubed steel bike frames more than
accepIttable for my own use.
Chalo
With modern AL frames, you can get a fairly steel like feel at a far
lower weight. �

I'm not so sure that can be generalized to an absolute rule. My steel
bike, roughly the same style and fitting out as my ali bikes, is
actually lighter by at least ten pounds than they are.

that's bull****.


It might be an
anomaly, and I know the makers are on a determined, permanent,
expensive weight saving programme.

My current Cannondale has a very stiff BB but not
nearly as stiff as the straight gauge first generation frame I bought
in 84/85. �It is slightly more stiff than the BB on my old Columbus SP
frame with a boat anchor heavy Cinellli cast BB. Overal, the Al frame
has a more lively feel. �IMO, it needs to be a little more stiff
through the front end for climbing. � Going for a hard ride in my
capacity as old-guy team mascot for racer dudes. -- Jay Beattie.

Keep those remarks down, will you. You're ten years younger than I am!
I feel pretty young.

Andre Jute
You can ride only one bike at a time


you can only blow smoke up the skirts of fools.

Andre Jute wrote:
On Apr 26, 3:28�am, Tom Ace wrote:
On Apr 25, 7:08�pm, Hank Wirtz wrote:

Didn't Sheldon once (or more often) mention that his wife Harriet had
built a fat-tube Al bike herself while attending college with Gary
Klein?
Yes.http://tinyurl.com/cey646

Tom Ace

Looks like it wasn't Gary Klein who had the idea but their professor.
Good work for the prof, a career for one of his students, eventually a
husband for another. Not a bad return for a practical tutorial.

Andre Jute
Teachers and preachers


idiot. the engineering precedes both klein /and/ his professor. what
klein did though, and for which he deserves full credit, is actually
/doing/ something with it. unlike you. the irony of the empty vessel
making the loudest sound it can on "engineering", yet missing something
so fundamental is quite incredible.

Andre Jute wrote:
On Apr 26, 2:35�am, Chalo wrote:
Andre Jute wrote:

Jimbo said of Klein that "they not only figured out the torsional
stiffness thing, but actually acted on it. �they deserve medals for
that."
Can you give us some references, preferably with pics, and maybe you
want to spin out a short par so we know to look for precisely what
you're referring to.
Gary Klein is often credited as being the first to offer a commercial
big-tube aluminum bike. �As far as I can tell, Harlan Meyers of Hi-E
beat him to it by a span of years, having brought his frame to market
in 1972, a year before Klein claims to have conceived the idea while
in college.

http://www.wooljersey.com/gallery/v/...osters/Hi-E/19...

Fat tubes are torsionally much stiffer than skinny ones. �This
accounts for the relative lack of BB sway in fat-tubed aluminum frames
versus traditional steel ones. �The problem "jim beam" has is in
believing it matters that much. �If one prefers the feel of a
torsionally stiff frame, a very fat-tubed and not-too-light aluminum
frame may be the most cost- and weight-effective way to attain that
end. �But many of us either don't care or prefer more springiness in
our frames.

Having become infatuated at one time with the superior stiffness of
big-tube aluminum frames, I now feel more or less agnostic on the
matter. �I believe that there is far more difference and more benefit
in a stiff crank and BB spindle, since using these has made various
otherwise inadequate skinny-tubed steel bike frames more than
acceptable for my own use.

Chalo

Thanks. Hindsight is such a wonderful thing: I got the big tubes, but
was expecting something *more* from the way Jumbo went on. But of
course, those big tubes weren't handed down from the finger of god;
they had to be scaled in the light of experience, and the processes
worked out.

Andre Jute
I'm not a know-all. I don't need to be. I know who to ask.

that sig is a classic - you don't ask people that actually know - you
just ask people that tell you what you want to hear! hubris, thy name
is andre jute.

On Apr 27, 1:35*am, Nick L Plate wrote:
On 26 Apr, 15:49, jim beam wrote:

Steel bikes are
proven.

yeah! *proven heavy. *proven fatigue vulnerable.

I've thought about the frame failures I have seen. *The failures of
top tube and main tube near to the head tube are, I believe to be due
to the builder not cutting an opening in the head tube to shoot the
top and main tube through. *By leaving the headtube intact, the area
is too stiff in comparison to the top and main tube. *This extra
stiffness is detrimental to the longevity of top and main tube because
it concentrates the bending loads to the end of the lug or butt.
Making the head tube joints a little less stiff will help to reduce
top and main tube failure. *This is more relevant with small frames
(short stiff headtube).

Huh? What breaks things is a lack of stiffness, Trevor. To stop them
breaking you want to make them stiffer. That means bigger tubes,
bigger welding or brazing surfaces (which through holes at the
junction may or may not achieve depending on design), internal or
external sleeving or flitch plates. Making tubes shorter,
triangulating them more thoroughly (by for instance shortening the
head tube), and so on will make the assembly stiffer and *less* likely
to break. You really should do some research on the difference between
a structure, which cannot fold even if the joints are pinned rather
than welded, and a mechanism, which folds at pinned joined. When a
bicycle frame breaks, it is because it was at least partly a
mechanism, because there was *movement*, so the last thing we want to
add is more scope for movement.

Andre Jute
Author of "Designing and Building Special Cars", published by
Batsford, London, which has several chapters about materials,
stiffness and structures.

Andre Jute wrote:
snip

Andre Jute
Author of "Designing and Building Special Cars", published by
Batsford, London, which has several chapters about materials,
stiffness and structures.

complete with math, metallography and fatigue analysis. not.

On Apr 27, 3:04*am, jim beam wrote:
Andre Jute wrote:
My steel
bike, roughly the same style and fitting out as my ali bikes, is
actually lighter by at least ten pounds than they are.

that's bull****.

If you think different, Jumbo, prove it. My bikes are at
http://www.audio-talk.co.uk/fiultra/...20CYCLING.html
and you can find the specs for yourself. You're going to fall flat on
your face again because once more you're blustering before you look up
the facts. And don't try to lie about the facts, because I'm watching
you, sonny.

Andre Jute
*You can ride only one bike at a time

you can only blow smoke up the skirts of fools.

You should stick to materials Jumbo. I'll send you nice bit of
leftover curtain material to make a skirt for yourself.

Andre Jute
Help out an aspirant transvestite today: give him a scalpel