Where are the inexpensive steel bikes?

In article 40d7d62c@darkstar, Benjamin Weiner
wrote:

Warren Block wrote:
Ryan Cousineau wrote:

There were never any Al/steel hybrids because those materials don't play
particularly well with each other for various technical reasons.

Guess my Fisher CR-7 doesn't exist, what with its imaginary aluminum
front triangle and hypothetical bolted-on steel rear triangle.

Just my luck. I make a stupid claim and there's three different readers
of this ng with different Al/steel bikes. Of course, my own stupidity
has drawn out stronger evidence for my thesis about progressive tube
replacement! So I'm even more right! I'm a frickin' genius!!

And did I mention modest?

Ahem. What I should have said is that these hybrids were rare because of
various technical reasons, basically meaning that you have to glue them
together.

I have an Easton Reflex MTB with aluminum main tubes and
steel fork, headtube, lugs and rear triangle. These were
glued together and are related to Raleigh Technia. (Technii?
Whatever the plural of Technium is.) Ryan's point about
the migration of CF into bikes via the rear triangle is
strengthened if anything by remembering all the frames
that had CF main triangle tubes and aluminum lugs (Specialized,
Trek, Giant, Vitus, etc). It's all about product
differentiation.

I think that was also about making frames easily. I suspect that casting
(forging?) Al lugs in a variety of sizes and cutting standard CF tubes
to length made both materials do what they did most easily, and meant
that producing a variety of frame sizes only required about three new Al
molds per size.

Even today, most CF frames use special rear dropouts: the dropout either
bolts to or is fabricated with tube ends that are bonded into the seat
and chain stays. The ends that joins to the seat tube can be adjusted to
various angles and is permanently bolted into place at the correct angle
when the frame is being made. This saves the manufacturer the pain of
stocking a different set of dropouts for each frame size.

Metal frames get around this by just welding or brazing the stay ends
directly to the metal dropout at whatever angle the frame calls for.

Spent my lunch hour bending my derailleur hanger into alignment,
--
Ryan Cousineau, http://www.sfu.ca/~rcousine/wiredcola/
President, Fabrizio Mazzoleni Fan Club

There is also catastrophic failure. Drop a wrench on an aluminum tube and
see what happens. Now repeat the test on steel, titanium and carbon. Which
one shows a dent? How will that dent alter the fatigue tests?

It's one thing to place a pristine frame on a machine and bend it back and
forth. It's something else to get the chain wedged in the stay before doing
the test.

-Dion

http://www.sheldonbrown.com/rinard/E...tigue_test.htm

The most salient conclusion from that test:

"The fact that aluminum and carbon frames in this test lasted longer
than the steel frames is not in our estimate a question of the
material, but the design effort. Not the material, but its skillful
use gives the result."

In other words, any of these materials (Al, Ti, steel, carbon) can
be used to make a durable, lighhtweight frame. Conversely, poor
design can lead to a weak and heavy frame, whatever material is used.

A dent would not qualify for warranty work as it was not caused by a defect
in the frame. Likewise for failures that were initiated by dents and
gouges.

-Dion

"Tai" wrote in message
om...
"Dion Dock" wrote in message
...
There is also catastrophic failure. Drop a wrench on an aluminum tube
and
see what happens. Now repeat the test on steel, titanium and carbon.
Which
one shows a dent? How will that dent alter the fatigue tests?

It's one thing to place a pristine frame on a machine and bend it back
and
forth. It's something else to get the chain wedged in the stay before
doing
the test.

-Dion

Are Al frames really that sensitive to corruption of the frame
integrity? Surely not, since mtn bikes get beat up all the time with
crashes. Bike makers would go back to steel instead of dealing with
warranty replacements.

Tai