crashed bike, replace or not replace?

I crashed my beloved Ti bike (3/2) because some jerk in an ambulance
decided to freak me out with the siren as he passed me (no I guess he
couldn't have it on all the way down and only turned it on as he
passed me on a narrow bridge).

Anyway, I'm ok and the bike wasn't in bad shape. It was on hard
concrete and there's a tiny dent (~1mm in diameter, not that deep) in
the back triangle fork about have way down.

My carbon front fork also had a small scratch. Doesn't seem to be
dented that much and hardly noticable. I was able to sand both down
until I could hardly feel them. I know this now was a bad idea since
I'm just losing more material but seemed like a good idea at the time
and gives you an idea that it wasn't very deep at all.

I got some scrapes on the rear derailleur, shifters and crank but
nothing so hard that it needed replacement or even real readjustment.
Kind of an eye sore but manageable.

How concerned should I be about the frame or the fork breaking
suddenly while on a ride? I went for a 20mile ride and didn't notice
any problems. Should I see an eventual crack form if it does break or
will the whole thing explode and leave me in the hospital?

Just post your replies here for everyone's benefit. Thanks.

Check your fork before and after every ride for stress cracks. A single
scratch into the epoxy layer of the material is all it takes for CF to
rapidly devlop stress cracks at that point. CF is after all a cloth, that
is in layers all held together with epoxy resin. It's the layering that
gives it it's tensile strength, and the epoxy that give it it's rigidity.

"Do not reply to e-mail. Post only" wrote in
message ...
I crashed my beloved Ti bike (3/2) because some jerk in an ambulance
decided to freak me out with the siren as he passed me (no I guess he
couldn't have it on all the way down and only turned it on as he
passed me on a narrow bridge).

Anyway, I'm ok and the bike wasn't in bad shape. It was on hard
concrete and there's a tiny dent (~1mm in diameter, not that deep) in
the back triangle fork about have way down.

My carbon front fork also had a small scratch. Doesn't seem to be
dented that much and hardly noticable. I was able to sand both down
until I could hardly feel them. I know this now was a bad idea since
I'm just losing more material but seemed like a good idea at the time
and gives you an idea that it wasn't very deep at all.

I got some scrapes on the rear derailleur, shifters and crank but
nothing so hard that it needed replacement or even real readjustment.
Kind of an eye sore but manageable.

How concerned should I be about the frame or the fork breaking
suddenly while on a ride? I went for a 20mile ride and didn't notice
any problems. Should I see an eventual crack form if it does break or
will the whole thing explode and leave me in the hospital?

Just post your replies here for everyone's benefit. Thanks.

On Thu, 15 Jul 2004 16:05:48 -0700, "Stephen Foley"
wrote:

Check your fork before and after every ride for stress cracks. A single
scratch into the epoxy layer of the material is all it takes for CF to
rapidly devlop stress cracks at that point. CF is after all a cloth, that
is in layers all held together with epoxy resin. It's the layering that
gives it it's tensile strength, and the epoxy that give it it's rigidity.

"Do not reply to e-mail. Post only" wrote in
message ...
I crashed my beloved Ti bike (3/2) because some jerk in an ambulance

What does Carbon Fiber (CF) frame have to do with a scratch or dent in
a Ti (Titanium) frame?

-B

On Thu, 15 Jul 2004 22:31:06 -0400, Badger_South
wrote:

On Thu, 15 Jul 2004 16:05:48 -0700, "Stephen Foley"
wrote:

Check your fork before and after every ride for stress cracks. A single
scratch into the epoxy layer of the material is all it takes for CF to
rapidly devlop stress cracks at that point. CF is after all a cloth, that
is in layers all held together with epoxy resin. It's the layering that
gives it it's tensile strength, and the epoxy that give it it's rigidity.

"Do not reply to e-mail. Post only" wrote in
message ...
I crashed my beloved Ti bike (3/2) because some jerk in an ambulance

What does Carbon Fiber (CF) frame have to do with a scratch or dent in
a Ti (Titanium) frame?

-B

Duh, ok, nevermind...

-B
....must read whole message...

On Thu, 15 Jul 2004 22:17:27 GMT, Do not reply to e-mail. Post only
wrote:

How concerned should I be about the frame or the fork breaking
suddenly while on a ride? I went for a 20mile ride and didn't notice
any problems. Should I see an eventual crack form if it does break or
will the whole thing explode and leave me in the hospital?

Just my opinions, based on largely inadequate information...

Frame: Probably no concern at all. It's hard to say with certainty,
by my guess from this distance is that you can probably ride it
without hazard.

Fork: Watch for crazing of the resin in the area that was sanded, and
inspect for any unusual flexing until you're comfortable...or replace
it if you're not. Carbon may give little or no warning of failure,
just like steel, aluminum, or anything else. The caveat here is that
fork failures tend to be harder to deal with, and are more likely to
cause a serious crash, than frame failures. If the crash didn't
involve a headlong impact into a fixed object with you aboard the
bike, and if the fork wasn't subject to being run over by something
large and heavy while the bike was down, the chances are good that the
fork has not been overstrained...but you will only find out for sure
*if* it fails.
--
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