Carbon Fork Damage

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Date: 11 Jul 2007 16:11:15
From: Allan Leedy
Subject: Carbon Fork Damage

Ti bike, carbon fork, metal steerer tube. It was involved in a crash with
injuries and a broken helmet. Only visible effect on bike was a twisted
seatpost. LBS wants to replace the forks, even though there isn't a mark or
a sign of stress or damage. Does that make any sense at all? As long as
there is a wheel fixed in the dropouts, it's hard for me to see how the
forks could be damaged or stressed by impact without leaving some visible
evidence.

Date: 12 Jul 2007 07:43:39
From: bjw@mambo.ucolick.org
Subject: Re: Carbon Fork Damage

On Jul 11, 9:46 pm, Allan Leedy <rale...@aracnet.com > wrote:
> > I can't help but think of the new Boeing Dreamliner when I read this post.
>
> Isn't that the truth! I said to someone that if this fork advice is for
> real, I'm never setting foot in that airplane. Ever.

They will have a pretty strict inspection regimen for it,
probably using ultrasound to sense internal flaws.
I bet one could use a similar test on bike forks, but
few would pay for it. They test aluminum airplanes too.
Most aluminum bikes and parts recieve only cursory
inspections, and I wouldn't want to fly in an aluminum
airplane that was maintained as haphazardly as a typical
aluminum bicycle.

Ben

Date: 11 Jul 2007 20:38:31
From: jim beam
Subject: Re: Carbon Fork Damage

Allan Leedy wrote:
> Ti bike, carbon fork, metal steerer tube. It was involved in a crash with
> injuries and a broken helmet. Only visible effect on bike was a twisted
> seatpost. LBS wants to replace the forks, even though there isn't a mark or
> a sign of stress or damage. Does that make any sense at all? As long as
> there is a wheel fixed in the dropouts, it's hard for me to see how the
> forks could be damaged or stressed by impact without leaving some visible
> evidence.
>

testing and caution are the keys to safe fork use - "crashed" or new.

assuming it passed close visual inspection:

1. grip the fork ends both in one hand and squeeze as hard as you can.
2. place fork between two blocks of wood so it bridges the gap. should
be able to support your full body weight.

in both cases, if testing makes any creaking or groaning or cracking
noises, discard and destroy. [same applied for any carbon componentry
in use - creaking and cracking noises are /bad/ news. do /not/
ignore!!!] of not, i'd continue use. i ride a "crashed" fork almost
daily. no problems.

Date: 13 Jul 2007 13:44:42
From: Callistus Valerius
Subject: Re: Carbon Fork Damage

> in both cases, if testing makes any creaking or groaning or cracking
> noises, discard and destroy. [same applied for any carbon componentry
> in use - creaking and cracking noises are /bad/ news. do /not/
> ignore!!!] of not, i'd continue use. i ride a "crashed" fork almost
> daily. no problems.
-----------
I was involved in a pack crash, I went down sideways on the non-drive side,
and the rider behind me rode over the seat stay, and left a tire burn on my
leg from his spinning rear tire. The bike was a Trek 5200. I've ridden
10,000 miles since on it, with no problem. It was years ago, and wasn't
aware that a problem with the CF could come about due to a situation like
this, so sometimes ignorance is bliss. Now with what I know, if I enter
these mass demolition derbys I ride my Trek 1000 with a cro-moly fork, and
MA3 wheels. I'll do the CF mashing.

Date: 13 Jul 2007 16:21:06
From: A Muzi
Subject: Re: Carbon Fork Damage

>> in both cases, if testing makes any creaking or groaning or cracking
>> noises, discard and destroy. [same applied for any carbon componentry
>> in use - creaking and cracking noises are /bad/ news. do /not/
>> ignore!!!] of not, i'd continue use. i ride a "crashed" fork almost
>> daily. no problems.

Callistus Valerius wrote:
> I was involved in a pack crash, I went down sideways on the non-drive side,
> and the rider behind me rode over the seat stay, and left a tire burn on my
> leg from his spinning rear tire. The bike was a Trek 5200. I've ridden
> 10,000 miles since on it, with no problem. It was years ago, and wasn't
> aware that a problem with the CF could come about due to a situation like
> this, so sometimes ignorance is bliss. Now with what I know, if I enter
> these mass demolition derbys I ride my Trek 1000 with a cro-moly fork, and
> MA3 wheels. I'll do the CF mashing.

"left a tire burn on my leg from his spinning rear tire"

Or a skid mark. Humans don't have nearly the torque you might imagine.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Date: 14 Jul 2007 02:24:13
From: Callistus Valerius
Subject: Re: Carbon Fork Damage

>
>
> "left a tire burn on my leg from his spinning rear tire"
>
> Or a skid mark. Humans don't have nearly the torque you might imagine.
> --
My bike was down on the ground sideways, and he went over my seat stay, when
his rear wheel come off of that, he spun the wheel, in the air, and it
landed on my leg, he crashed after that also. About 20 of us went down.
Like you know, these things happen quick, but when when they're happening it
seems like it's in slow motion. I don't know how he got on top of the seat
stay, but I'm guessing he got shoved from behind. It was quite a mess.
Nothing like the total silence immediately after everyone was on the ground.
It kind of made me mad, because I don't like being in the middle of the
pack, so I fight to be on the side of it, but I let my guard down, and by
the time the crash hit, I was three riders in, so there was no escape.

Date: 13 Jul 2007 06:56:33
From: jim beam
Subject: Re: Carbon Fork Damage

Callistus Valerius wrote:
>> in both cases, if testing makes any creaking or groaning or cracking
>> noises, discard and destroy. [same applied for any carbon componentry
>> in use - creaking and cracking noises are /bad/ news. do /not/
>> ignore!!!] of not, i'd continue use. i ride a "crashed" fork almost
>> daily. no problems.
> -----------
> I was involved in a pack crash, I went down sideways on the non-drive side,
> and the rider behind me rode over the seat stay, and left a tire burn on my
> leg from his spinning rear tire. The bike was a Trek 5200. I've ridden
> 10,000 miles since on it, with no problem. It was years ago, and wasn't
> aware that a problem with the CF could come about due to a situation like
> this, so sometimes ignorance is bliss. Now with what I know, if I enter
> these mass demolition derbys I ride my Trek 1000 with a cro-moly fork, and
> MA3 wheels. I'll do the CF mashing.
>
>
but your steel will bend before their carbon will crack. why protect
/their/ gear by sacrificing your own?

Date: 13 Jul 2007 17:53:31
From: Crescentius Vespasianus
Subject: Re: Carbon Fork Damage

> > I was involved in a pack crash, I went down sideways on the non-drive
side,
> > and the rider behind me rode over the seat stay, and left a tire burn on
my
> > leg from his spinning rear tire. The bike was a Trek 5200. I've ridden
> > 10,000 miles since on it, with no problem. It was years ago, and wasn't
> > aware that a problem with the CF could come about due to a situation
like
> > this, so sometimes ignorance is bliss. Now with what I know, if I enter
> > these mass demolition derbys I ride my Trek 1000 with a cro-moly fork,
and
> > MA3 wheels. I'll do the CF mashing.
> >
> >
> but your steel will bend before their carbon will crack. why protect
> /their/ gear by sacrificing your own?
--------
LOL, you got me there.

Date: 11 Jul 2007 16:48:47
From: g
Subject: Re: Carbon Fork Damage

I crashed as well and have ridden safely for 3 years. But I know how the
impact was delivered to my shoulder and not the bike. My helmet was
fractured as well. Still based on my accident which will be different than
yours it's your call and your life on the line.
You have to judge if the bike fork was impacted.
My accident happened so fast I did not know that I had a fractured helmet,
but saw a bruise on my head 2 days later, and checking the helmet -
fractured !
Collar bone broken, lung punctured. To this day collar bone still not healed
but I ride still - more conservatively.
Good luck-
something to consider about a carbon fork, is that it could be damaged and
you won't know it by looking at it. There is resin and carbon fibers. It
could be weakened without showing a craze in the paint or top surface.
Other forum regulars should comment, take advise as you see fit.
greg :)
"Allan Leedy" <raleedy@aracnet.com > wrote in message
news:C2BAB1A3.DFD%raleedy@aracnet.com...
> Ti bike, carbon fork, metal steerer tube. It was involved in a crash with
> injuries and a broken helmet. Only visible effect on bike was a twisted
> seatpost. LBS wants to replace the forks, even though there isn't a mark
> or
> a sign of stress or damage. Does that make any sense at all? As long as
> there is a wheel fixed in the dropouts, it's hard for me to see how the
> forks could be damaged or stressed by impact without leaving some visible
> evidence.
>

Date: 12 Jul 2007 03:19:02
From: Steve Gravrock
Subject: Re: Carbon Fork Damage

On 2007-07-11, g <friend@public.com > wrote:

> something to consider about a carbon fork, is that it could be damaged and
> you won't know it by looking at it. There is resin and carbon fibers. It
> could be weakened without showing a craze in the paint or top surface.

Indeed. I had a carbon fork that was apparently damaged in shipping. It
looked fine initially but showed cracks on the inside of each blade
coming forward from the wide spot below the crown within 30 miles.

Date: 12 Jul 2007 02:06:40
From: Callistus Valerius
Subject: Re: Carbon Fork Damage

> something to consider about a carbon fork, is that it could be damaged and
> you won't know it by looking at it. There is resin and carbon fibers. It
> could be weakened without showing a craze in the paint or top surface.
=======
I can't help but think of the new Boeing Dreamliner when I read this post.

Date: 12 Jul 2007 07:37:32
From: Derk
Subject: Re: Carbon Fork Damage

Callistus Valerius wrote:

> I can't help but think of the new Boeing Dreamliner when I read this post.
I have a cousin who works in the aviation industry and she told me that they
have to check a wing with ultrasound after a hammer has been dropped by a
technician.

Derk

Date: 11 Jul 2007 21:46:30
From: Allan Leedy
Subject: Re: Carbon Fork Damage

Isn't that the truth! I said to someone that if this fork advice is for
real, I'm never setting foot in that airplane. Ever.

On 7/11/07 7:06 PM, in article
Q0gli.6716$Od7.1680@newsread1.news.pas.earthlink.net, "Callistus Valerius"
<jazzyboss@hotmail.com > wrote:

>> something to consider about a carbon fork, is that it could be damaged and
>> you won't know it by looking at it. There is resin and carbon fibers. It
>> could be weakened without showing a craze in the paint or top surface.
> =======
> I can't help but think of the new Boeing Dreamliner when I read this post.
>
>

Date: 12 Jul 2007 19:03:33
From: Phil
Subject: Re: Carbon Fork Damage

"Allan Leedy" <raleedy@aracnet.com > wrote in message
news:C2BB0036.1185%raleedy@aracnet.com...
> Isn't that the truth! I said to someone that if this fork advice is for
> real, I'm never setting foot in that airplane. Ever.

Plan on driving a lot in upcoming years.

--
Phil

Date: 11 Jul 2007 22:03:44
From: jim beam
Subject: Re: Carbon Fork Damage

Allan Leedy wrote:
> Isn't that the truth! I said to someone that if this fork advice is for
> real, I'm never setting foot in that airplane. Ever.

it's b.s. chopper rotors have been composites for 30 years. they put
up with all kinds of abuse, including bullet holes.

>
>
> On 7/11/07 7:06 PM, in article
> Q0gli.6716$Od7.1680@newsread1.news.pas.earthlink.net, "Callistus Valerius"
> <jazzyboss@hotmail.com> wrote:
>
>>> something to consider about a carbon fork, is that it could be damaged and
>>> you won't know it by looking at it. There is resin and carbon fibers. It
>>> could be weakened without showing a craze in the paint or top surface.
>> =======
>> I can't help but think of the new Boeing Dreamliner when I read this post.
>>
>>
>

Date: 11 Jul 2007 18:41:37
From: mrbubl
Subject: Re: Carbon Fork Damage