From: tran@kepler.Stanford.EDU (Hy Tran)
Subject: Re: Summ. of Frame Materials for Review (enough already)
Organization: stanford
Date: Mon, 31 Aug 1992 22:44:15 GMT

Before more misinformation gets posted, let me give a few pointers to
readily available references:

F. R. Whitt and D. G. Wilson, "Bicycling Science", MIT Press 1982.
This book, though somewhat dated, has an excellent chapter on
materials and stress.  Somewhat demanding reading for those who are
quantitatively impaired.

John Kukoda, `In Praise of Steel', in "Bicycling", July 1988.  In
addition to a good review of steel frame construction (though he is
not very quantitative), this article includes an extensive table of
the tubesets offered by major manufacturers--including Columbus,
Tange, Reynolds, True Temper, and Vitus (steel).

ASM International, "ASM Metals Reference Handbook", Metals Park, Ohio,
1983.  The "Lite" version of the 10+ volume "Metals Handbook" from the
same publisher.  The 10+ volume series has more information about all
sorts of metals than you will ever need to know.  The "Lite" version
is sort of the "Cliff Notes" version, but is a good starting point.

For those of you who are stress and strain impaired, let me add these:

Crandall, Dahl, and Lardner, "An Introduction to the Mechanics of
Solids", McGraw-Hill.

Roark, "Formulas for Stress and Strain", McGraw-Hill.

To reiterate: Frame stiffness is a function of the material and the
geometry.  None of the various alloy steels differ in intrinsic
stiffness by more than a few percent, but the increased strengths may
allow a thinner (and therefore lighter) tube.  Given two tubes with
identical OD's, and varying wall thicknesses, the thicker-walled tube
will be heavier, and "stiffer."  Given two tubes with arbitrary
geometry, I can make them have similar "stiffness" (assuming
cantilevered beams) with different weights--or similar weights, and
radically different stiffnesses.

Mr. Kunich's observation that his "el cheapo" bicycle was 1 lb heavier
than his Reynolds 531 bike would indicate that the geometries were
different.

If Mr. Kunich wishes to build frames using mild steel, say AISI 1214,
(and he can get someone to make double-butted tubesets in 0.9/0.6/0.9
mm with that material), I'm sure he can build a frame without paying
the several hundred $$ that Columbus charges (or rather, Nova Cycle
Supply charges for Columbus tubesets).  I'm sure he will be able to go
on a few rides with the mild steel frame, and not cause permanent
deformation.  But I have serious doubts about the longevity of such a
frame.

As for the assertion by some professional cyclists that after a season
or two of racing, their frames feel "whippy":  I am unaware of any
objective studies that document this effect.  Repainting the "whipped"
frames with structural paint might, in fact, restore their previous
pristine behavior.

Finally: TSX is Columbus's answer to Tange Prestige Ultralight.  It is
a very thin-walled tubing (0.8/0.6/0.8 mm from the table in Kukoda's
article).  TSX frames, with identical lugs, will be marginally lighter
than SLX frames.  They may or may not be more compliant (since TSX has
helical reinforcements along the entire tube, standard analysis
methods are more difficult to apply).  Whether these few ounces of
weight are worth the money is between you and your wallet.

Hy Tran
tran@sun-valley.stanford.edu