Re: [CR]Re: Debunking time again


Example: Production Builders:LeJeune

Date: Thu, 30 May 2002 12:24:10 -0700 (PDT)
From: Tom Dalton <tom_s_dalton@yahoo.com>
Subject: Re: [CR]Re: Debunking time again
To: classicrendezvous@bikelist.org
In-Reply-To: <20020530.134741.-148969.12.richardsachs@juno.com>


I'm not sure you took my comments in the spirit in which they were intended, or that I have fully understood the intent of your message. What I was suggesting is that while there may not be an appreciable difference between two otherwise identical bikes, one with tubes made from alloy A with heart treatment 1 and one with tubes of alloy B / heat treatment 2, these alloys and heat treatments are not just conjured up to pull the wool over the eyes of hapless retail bike buyers, or even hapless engineers at bike companies. Metallurgical differences are real, and exist to meet real demands brought about by a world of potential end uses, even if certain of the effects of these differences may be negligable in certain end uses.

For example, the Reynolds 753 material was developed to meet the yield strength requirements of a super-thin-walled tubeset because the 531 material would not be adequately strong at the desired gauges. 753 had a real edge in yield strength that made it strong enough to meet the real demands of light gauge tubes, but the modulus of steel is fixed so the thin tubes don't really work because they are too flexy. By the time Reynolds drew the 753 material into tubes that were thick enough not to noodle around under a strong rider, the added stregth imparted by the material was unnesessary... and in the end other differences (fatigue strength?) may even have contributed to increased failure rates. Tom Dalton Bethlehem, PA

Richard M Sachs <richardsachs@juno.com> wrote: Tom Dalton writes: snip: <...This assumes that consumers, including engineers spec'ing steels for bike tubes, turbine blades, surgical instruments, etc. are universally idiotic...> (continued in the text below)

uh, i think we have a winner! at the risk of losing friends on the list by agreeing 100% with this here statement, i'll only say that (as far as materials go...) there is a 'this year's flavor' with regards to material, joining processes, shapes, guages, etcetera. (nearly) all the stuff presented to the consumer base as a choice worthy of consideration is made for industrial use, read: production bicycle making. bread and butter bikes. price point bikes. 'i just went to the mall and bought this here bike' bikes.

and guys-don't bust me up on this. it's only my opinion! you don't have to believe it to the degree that i do. e-RICHIE chester, ct ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

On Thu, 30 May 2002 10:21:04 -0700 (PDT) Tom Dalton writes:
>
> The Bohemian Bicycles website contains Scot Nichol's 6-part series
> about frame materials. It is somewhat general, but quite
> informative. It don't know a lot about materials science, but I did
> take one undergraduate course and Nichol's information was
> consistent with what I learned in that class. I think what Steven
> is driving at is that the mechanical properties of a steel tube that
> would influence ride (not durability, not yield strength) depend
> primarily on the geometry of the tube (wall thickness, diameter, and
> subtler aspects of material distribution dictated by tapers and
> butting). The density of steels is essentially constant as is the
> elastic modulus, therefore "stiffness" and weight should not change
> with different alloys, assuming the tubes are dimensionally
> identical. The catch is that a carbon steel bike would be pretty
> frail if the tubes were thin-walled and oversized. It would be
> light and stiff, but a collision with a pothole may exceed it's
> yield strength.
> The above is consistent with what they teach you in school, in the
> real world of frame building things may be different, at least in
> subtle ways. Personally I've never ridden two frames of differing
> materials that were otherwise similar enough to provide adequate
> control to assess the "feel" of different alloys and heat
> treatments... but based on what I've read, I doubt I'd feel a
> difference. Of course alloys still matter for other reasons,
> otherwise they wouldn't exist. Taken to the exteme, suggesting
> otherwise implies that steel companies "invent" special, expensive
> materials to screw consumers, when plain carbon steel would serve
> all purposes adequately. This assumes that consumers, including
> engineers spec'ing steels for bike tubes, turbine blades, surgical
> instruments, etc. are universally idiotic. Hey, I'm no lover of
> engineers, but I'll conceed that this is not the case.
> Tom Dalton, with apologies to engineers, in Bethlehem, PA
> NortonMarg@aol.com wrote: In a message dated 5/30/02 7:07:19 AM
> Pacific Daylight Time,
> monkeylad@mac.com writes:
>
> << I'm sure most people will chime in that I'm just full of it.
> Before
> you react look for the article in Bicycle Guide and look at the
> materials used in bike construction 40 years ago. Also note that
> we're talking about ride and not weight, longevity, ETC. . . Like
> everyone I want to believe that it really does matter since I'm
> paying extra for quality tubing, but when it comes to ride it just
> doesn't matter. I'm now off to put on my asbestos underwear. >>
>
> Have to disagree. Magazines publish articles to fill space and sell
>
> magazines. I've said this before and I'll say it again, Albert
> Eisentraut was
> one of the first American builders to vary the tubing gauges in a
> frame, not
> just using the standard "tube set". It made a HUGE difference in
> ride quality
> and a minuscule difference in weight. If what you are saying is that
> you can
> get a similar ride quality from cheap tubing (with a weight
> penalty), that's
> a somewhat fair statement. However, the cheaper, heavier steel
> tubing doesn't
> allow the artistic and talented frame builder to design in the
> subtleties
> that varying the best quality of tubes allows. Your statement would
> be fully
> true if subtlety did not exist in the universe.
> The smartest article I remember reading on the subject had to do
> with telling
> riders it's not the "steel" that matters, it's the "tubing". Tube
> configuration, wall thickness, taper, etc. matters more to a
> finished frame
> than "what steel is it?"
> Caeterus paribas, assuming first class workmanship.
> Stevan Thomas
> Alameda, CA