Re: "brittle" vs. non-ductile

jim beam <spamvor...@xxxxxxxxxxxxxxx> wrote:
Peter Cole wrote:
Then how (if there are "warning signs") could there be:
"a lot of people out there riding on damaged (broken) carbon frames &
forks that aren't aware of it." ?
simply pay attention big guy.
We all know it's pointless to argue with "jim beam," but since others
are reading: I think the advice he gives below is practically useless
for most people.
1. the bike comes with an owners manual outlining inspection and
warnings.
In America, warnings are attached to every consumer device. Our
society is perpetually crying "Wolf!" and most people are no longer
believing the warnings. I believe we've reached a point where the
warnings serve only as legal ammunition in a court action.

Any consumer actually reading his CF bike's manual would have to
distinguish whether the CF inspection warnings are any more serious
than statements like "Always check the tightness of every bolt before
any ride" and "Never ride any bicycle at night." Most will assume all
such warnings are legal smokescreens.

2. ask advice on this forum from people that are familiar with the
material and its failures.
:-) Trouble is, some poor sucker might believe advice from "jim
beam"!

3. ask bike shop owners that are familiar with the material and its
failures.

frkrygow@xxxxxxxxx wrote:
Correct me if I'm wrong (Andy? Mike? Sheldon?), but I don't think
all bike shop owners get extensive training in evaluating CF damage.
I've been in bike shops where the kid on duty couldn't operate a quick
release properly! No, he wasn't the owner, but how does the average
consumer tell the difference?

I don't think the typical American sport cyclist has any idea about
the true advantages and disadvantages of CF. IMO, he has no
understanding deeper than "Lance used this. It's 30 grams lighter and
it looks cool. Buycycling gave it 7 chainrings. It's going to
finally let me beat Fred up that hill."

And I think it's a bad idea to whittle the practical factor of safety
down to the point where the typical American sport cyclist has to
pretend to be a CF-certified airframe mechanic. It's like designing
the next Mazda Miata with an all-composite suspension system, and
hoping nobody ever hits a curb.

A Muzi <am@xxxxxxxxxxxxxxxx> wrote:
Right.
Yes, we can sometimes spot damage. But we are clear that our inability to see damage is not an imprimatur of soundness. When in doubt post-crash we suggest replacement. Some riders do, some do not.

Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet have, test equipment to nondestructively spot anomalies and/or damage in composite materials for the Dreamliner. Boeing spokesman pointedly noted that rapping a structural member with a quarter, the previous standard test, is no longer considered sufficient to establish airworthiness.

carlfogel@xxxxxxxxxxx wrote:
In a bold new move, Nepalese pre-flight inspectors now slaughter goats
instead of using the venerable coin-tapping rendered useless by
inflation:

http://www.freerepublic.com/focus/f-news/1890995/posts

Does that work with Chinese carbon BSOs? Or only Nepali? (I once filed an H-1B for a Tibetan, claiming I needed a Tibetan bike mechanic to work on Tibetan bikes. INS signed off right away on that one!)

We have a copy of Gene Daniels' all-time-best wheelbuilding directions on our truing stand [I paraphrase] "sprinkle some chicken blood, do a little dance (counterclockwise) holding a bag of spokes..."

I suppose a sacrificed goat can add that little je ne sais quoi when the manufacturer doesn't either.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
.

Relevant Pages

  • Re: "brittle" vs. non-ductile
    ... warnings are attached to every consumer device. ... I don't think the typical American sport cyclist has any idea about ... we can sometimes spot damage. ...
    (rec.bicycles.tech)
  • Re: "brittle" vs. non-ductile
    ... forks that aren't aware of it." ... believing the warnings. ... all bike shop owners get extensive training in evaluating CF damage. ... just like you wouldn't stand on a plank that made cracking noises under your weight, don't ride carbon that does the same. ...
    (rec.bicycles.tech)
  • Re: "brittle" vs. non-ductile
    ... believing the warnings. ... we can sometimes spot damage. ... test equipment to nondestructively spot anomalies and/or damage in ...
    (rec.bicycles.tech)
  • Re: "brittle" vs. non-ductile
    ... believing the warnings. ... we can sometimes spot damage. ... Chicago Trib last Sunday says Boeing is 'developing' i.e., doesn't yet have, test equipment to nondestructively spot anomalies and/or damage in composite materials for the Dreamliner. ...
    (rec.bicycles.tech)
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