From: jobst.brandt@stanfordalumni.org
Subject: Re: Carbon frame intregrity after accident
Newsgroups: rec.bicycles.tech
Message-ID: <4%Rpb.3553$Wy2.42989@typhoon.sonic.net>
Date: Tue, 04 Nov 2003 18:13:20 GMT

Mike Jacoubowsky writes:

>> Consider the benefits of riding a well built custom steel frame
>> that you can use or dent without concern and ride downhill on a
>> mountainous course without visualizing a crash over the side as the
>> front wheel breaks away.  I often think about riders I see when
>> descending a series of hairpins high over an abyss in the alps.

> You need to get with the program here and recognize that frame
> durability has much less to do with the material (whether it be
> steel, aluminum, carbon, ti or bamboo) and much more to do with how
> it's built.  You hint at it when you talk about a "well built"
> frame, but then add "custom steel" as if that somehow guarantees a
> better bike.

That was mainly to say that if you are willing to pay extra for a
space age frame, you might as well get a custom built steel frame.
Steel frames generally do not disintegrate as some of the fiber frames
have according to reports here and from bicycle shops.  I'm not
hinting.

> The numbers of failed lightweight steel frames are considerable, yet
> that doesn't make it appropriate to indict steel as a frame
> material.  But when you build frames out of steel at 3.5 lbs and
> below (as many custom steel frame builders, as well as production
> bikes, will do), it's no surprise that they fail.

The difference is the mode of failure.  I and riding companions have
had steel frame failures, all of which could be safely ridden after
the fault was discovered.

> Similarly, you can build a near-indestructible bike out of aluminum,
> carbon or ti... or you can build one that's on the bleeding-edge of
> what's possible to do, and then wonder why it failed.

I don't doubt that you could but the mode of failure of current
composite frames has a spooky nature to it, almost terrifying.  One
local rider descended a steep forest road (Tunitas Creek Rd) and had
the fork disintegrate on the flat runout after the descent.

> A more valid point would be that the endless pursuit of ever-lighter
> bicycles often involves compromises in terms of durability and
> longevity.  But to imply that the use of a particular frame material
> may send somebody hurtling into an abyss in the alps goes beyond the
> norm for hyperbole, even here on rec.bicycles.tech.

The reason for using these frame materials IS to get lighter and
lighter... and more expensive to increase boasting rights.  It runs
parallel to the larger and larger SUV with black everything offset by
chrome.

Jobst Brandt
jobst.brandt@stanfordalumni.org