KEVLAR FORKS



D

Dorian Smith

Guest
Any word on the strength of Kevlar forks? Yesterday I came upon an accident
on a local bike trail. The rider had struck a post and was paralyzed from
the neck down. During the impact, his forks had snapped just below the
brakes. The wheel was still attached. I examined the severed part of the
forks and noted that they were cleanly broken.

Not only did this accident firmly convince me to wear a helmet and ride
safely, but I'm now suspicious of non-metal materials. Should I be? The
rider said the bike was a two-year old Trek with Kevlar forks.
 
Dorian Smith wrote:
> Any word on the strength of Kevlar forks? Yesterday I came upon an accident
> on a local bike trail. The rider had struck a post and was paralyzed from
> the neck down. During the impact, his forks had snapped just below the
> brakes. The wheel was still attached. I examined the severed part of the
> forks and noted that they were cleanly broken.
>
> Not only did this accident firmly convince me to wear a helmet and ride
> safely, but I'm now suspicious of non-metal materials. Should I be? The
> rider said the bike was a two-year old Trek with Kevlar forks.
>
>

I've never heard of kevlar forks. Were they carbon?
 
On Sun, 20 Jun 2004 18:58:49 +0100, Zog The Undeniable
<[email protected]> wrote:

>Dorian Smith wrote:
>> Any word on the strength of Kevlar forks? Yesterday I came upon an accident
>> on a local bike trail. The rider had struck a post and was paralyzed from
>> the neck down. During the impact, his forks had snapped just below the
>> brakes. The wheel was still attached. I examined the severed part of the
>> forks and noted that they were cleanly broken.
>>
>> Not only did this accident firmly convince me to wear a helmet and ride
>> safely, but I'm now suspicious of non-metal materials. Should I be? The
>> rider said the bike was a two-year old Trek with Kevlar forks.
>>
>>

>I've never heard of kevlar forks. Were they carbon?


Dear Zog,

The fork in question may not have been Kevlar, but Kevlar
forks undeniably exist:

http://www.hillbrick.com.au/products/products_columbus_supermuscle_fork.html

Carl Fogel
 
primarily carbon, but with some kevlar fiber to augment the vibration
characteristics. kevlar is not as strong as carbon, but from what i
understand, individual fibers can be less brittle, so you sometimes see
kevlar as "fail safe" where the component can break but not separate.

[email protected] wrote:
> On Sun, 20 Jun 2004 18:58:49 +0100, Zog The Undeniable
> <[email protected]> wrote:
>
>
>>Dorian Smith wrote:
>>
>>>Any word on the strength of Kevlar forks? Yesterday I came upon an accident
>>>on a local bike trail. The rider had struck a post and was paralyzed from
>>>the neck down. During the impact, his forks had snapped just below the
>>>brakes. The wheel was still attached. I examined the severed part of the
>>>forks and noted that they were cleanly broken.
>>>
>>>Not only did this accident firmly convince me to wear a helmet and ride
>>>safely, but I'm now suspicious of non-metal materials. Should I be? The
>>>rider said the bike was a two-year old Trek with Kevlar forks.
>>>
>>>

>>
>>I've never heard of kevlar forks. Were they carbon?

>
>
> Dear Zog,
>
> The fork in question may not have been Kevlar, but Kevlar
> forks undeniably exist:
>
> http://www.hillbrick.com.au/products/products_columbus_supermuscle_fork.html
>
> Carl Fogel
 
"jim beam" <[email protected]> wrote in message
news:[email protected]...
> primarily carbon, but with some kevlar fiber to augment the vibration
> characteristics. kevlar is not as strong as carbon, but from what i
> understand, individual fibers can be less brittle, so you sometimes see
> kevlar as "fail safe" where the component can break but not separate.


It's actually a bit more complicated. Kevlar is actually about as strong in
tension as a high strength carbon fiber and quite a bit stronger than a high
modulus (stiffness) carbon/graphite fiber. Kevlar is however considerably
less stiff which is important in bicycle technology since you will always be
aware of stiffness differenses even if you never come close to the stress
necessary for failure. Kevlar is also poorer in compression which makes
design a bit trickier. It is tougher though which explains why I'd rather
have a Kevlar vest than a carbon fiber one.
 
The rider said they were Kevlar. The bike looked like a high end model. The
rider said he had ridden 3,500 miles in two years. When I looked at the
break, it appeared to be a fibrous material surrounding an inner metal tube.
I may be wrong about the metal tube. Both forks were sheared almost as
cleanly as if they had been cut with a circular saw.

"Zog The Undeniable" <[email protected]> wrote in message
news:40d5d1b5.0@entanet...
> Dorian Smith wrote:
> > Any word on the strength of Kevlar forks? Yesterday I came upon an

accident
> > on a local bike trail. The rider had struck a post and was paralyzed

from
> > the neck down. During the impact, his forks had snapped just below the
> > brakes. The wheel was still attached. I examined the severed part of the
> > forks and noted that they were cleanly broken.
> >
> > Not only did this accident firmly convince me to wear a helmet and ride
> > safely, but I'm now suspicious of non-metal materials. Should I be? The
> > rider said the bike was a two-year old Trek with Kevlar forks.
> >
> >

> I've never heard of kevlar forks. Were they carbon?
 
On Sun, 20 Jun 2004 15:51:07 -0700, Dorian Smith wrote:

> The rider said they were Kevlar. The bike looked like a high end model. The
> rider said he had ridden 3,500 miles in two years. When I looked at the
> break, it appeared to be a fibrous material surrounding an inner metal tube.
> I may be wrong about the metal tube. Both forks were sheared almost as
> cleanly as if they had been cut with a circular saw.
>
> "Zog The Undeniable" <[email protected]> wrote in message
> news:40d5d1b5.0@entanet...
>> Dorian Smith wrote:
>>> Any word on the strength of Kevlar forks? Yesterday I came upon an

> accident
>>> on a local bike trail. The rider had struck a post and was paralyzed

> from
>>> the neck down. During the impact, his forks had snapped just below the
>>> brakes. The wheel was still attached. I examined the severed part of the
>>> forks and noted that they were cleanly broken.
>>>
>>> Not only did this accident firmly convince me to wear a helmet and ride
>>> safely, but I'm now suspicious of non-metal materials. Should I be? The
>>> rider said the bike was a two-year old Trek with Kevlar forks.
>>>
>>>

>> I've never heard of kevlar forks. Were they carbon?




Please correct me if I'm wrong here. Am I to understand that you were
questioning somebody who was just in an accident and paralyzed from the neck
down?? Aren't your priorities a bit screwed up?? And, the guy was willing
to talk to you about his fork?? I would have been freakin' out if I were
unable to move. I wouldn't give a **** about my fork at that moment.

Did the fork break and cause the crash? Or did hitting the post cause the
fork to break? Just confirming here because you said "during the impact."
If it is the second, then that should not alter your decision to ride with
non-metal materials. Hit something hard enough and it would matter what
material the fork was made from.
--
Skuke
Reverse the domain name to send email
 
"Dorian Smith" <[email protected]> wrote in message
news:[email protected]...
> Any word on the strength of Kevlar forks? Yesterday I came upon an

accident
> on a local bike trail. The rider had struck a post and was paralyzed from
> the neck down.


Got a local news link?



winnard
 
"Dorian Smith" <[email protected]> wrote in message
news:[email protected]...
> Any word on the strength of Kevlar forks? Yesterday I came upon an

accident
> on a local bike trail. The rider had struck a post and was paralyzed from
> the neck down. During the impact, his forks had snapped just below the
> brakes. The wheel was still attached. I examined the severed part of the
> forks and noted that they were cleanly broken.
>
> Not only did this accident firmly convince me to wear a helmet and ride
> safely, but I'm now suspicious of non-metal materials. Should I be? The
> rider said the bike was a two-year old Trek with Kevlar forks.


That's horrible. Do you know it he'll be paralyzed for the rest of his
life?

Dave
 
"Dorian Smith" <[email protected]> wrote in message
news:[email protected]...
> The rider said they were Kevlar. The bike looked like a high end model.

The
> rider said he had ridden 3,500 miles in two years. When I looked at the
> break, it appeared to be a fibrous material surrounding an inner metal

tube.

Did the fibers have color to them? I believe Kevlar's natural color is
yellow.

--
Phil, Squid-in-Training
 
> > Dorian Smith wrote:
> > > Any word on the strength of Kevlar forks? Yesterday I came upon an

> accident
> > > on a local bike trail. The rider had struck a post and was paralyzed

> from
> > > the neck down. During the impact, his forks had snapped just below the
> > > brakes. The wheel was still attached. I examined the severed part of the
> > > forks and noted that they were cleanly broken.
> > >
> > > Not only did this accident firmly convince me to wear a helmet and ride
> > > safely, but I'm now suspicious of non-metal materials. Should I be? The
> > > rider said the bike was a two-year old Trek with Kevlar forks.
> > >
> > >

Where did this occur? I could not find this with a google news search.
 
On Sun, 20 Jun 2004 10:41:18 -0700, "Dorian Smith"
<[email protected]> wrote:

>Any word on the strength of Kevlar forks? Yesterday I came upon an accident
>on a local bike trail. The rider had struck a post and was paralyzed from
>the neck down. During the impact, his forks had snapped just below the
>brakes. The wheel was still attached. I examined the severed part of the
>forks and noted that they were cleanly broken.
>
>Not only did this accident firmly convince me to wear a helmet and ride
>safely, but I'm now suspicious of non-metal materials. Should I be? The
>rider said the bike was a two-year old Trek with Kevlar forks.


Something about this strikes me very oddly. Several somethings, in
fact.

To address only the technical issue raised: The metal tube inside the
stub of the fork that was still on the bike doubtless was the metal
yoke and mounting tube assembly for the carbon fiber fork legs. The
end of the tubes would be the logical failure point for such an
assembly in an impact. This does not sound like a Trek fork, however;
for one thing, they make no mention of Kevlar in their literature.
Several other carbon component producers use Kevlar to reinforce the
carbon fiber matrix; such hybrid composites are actually quite common
in the aerospace and military sectors.

As for the total story...

I find it very odd that a paralysis-inducing incident did not make it
into the local news (print or broadcast) in the Tacoma area,
particularly when such an incident would have involved a technically
challenging extraction from a trail-riding area.

I find it even more odd that the cyclist involved was conscious, let
alone coherent enough to answer questions about the bike. I find it
quite peculiar that if you were the first finder of the incident, you
were examining the bike instead of getting help, though I suppose that
it's conceivable that if you were carrying a cell phone and called 911
from the site, the instructions would have been to stay put, do
nothing, and wait for help to arrive. In that case, I think I might
have been looking at the wreckage myself. If you weren't the first
arriver, I find it odd that you had access to the bike; the emergency
people on the scene ought to have been keeping anyone with no
necessary skills or equipment well away from the incident.

Many things about this scenario don't add up.

Obligatory helmet observation: You didn't say if the rider was so
equipped. I will not fault those who maintain that they'd rather
leave such a site in a body bag than in permanent paralysis. They can
take their chances their way, and I'll take mine in the manner I
prefer.

Trollometer rating: moderate to high.
 
The courage of the rider is a second and even more compelling story. There
were about eight riders in his pace line, nearly all were teenagers (he's
47) who were from a church-related group and training for the
Seattle-to-Portland ride next month. I learned they were from a church when
a co-leader said a prayer over the prostrate rider. Just before the
accident, I was riding about a quarter mile behind with a young man on a
mountain bike who couldn't keep up with the pace line. When we reached the
accident site, someone had already called 911. The others were standing
around waiting for the ambulance. At one point two riders tried to lift the
injured rider's head to give him a drink of water. I suggested they not try
to move his neck. We then sent riders ahead and behind along the trail to
instruct other riders to dismount and walk by the scene. While we waited, I
held up my helmet to shade him from the sun (temperature was in the 80s --
hot for western Washington). He talked almost conversationally about the
bike and how the accident happen. All the while he laid on his back with his
arms and legs stretched out and unmoving.

The young men were somewhat stunned and didn't know what to do or how to
act. He talked to them in an unanxious voice, as if he were trying to help
them maintain composure. Occasionally, he talked about the injury. (That's
how I learned the details.) He was concerned that he couldn't move his
limbs, but once or twice he felt a nudge when someone touched him. That
brought him some comfort.

We probably waited 15-20 minutes before the EMTs arrived. I then left
because there were too many people hanging around and staring at him. I was
irritated by some of the cyclists who passed by uttering *Poor guy* and *Oh,
I'm so sorry.* and the worst was *Jesus, really?!! He can't move!?* I
remember from First Aid training not to utter pessimistic comments to help
the victim maintain composure.

I've been trying to locate the medical sources to find out the results of
his injury. I hope to find out tomorrow or the next few days.

He was a very brave man. I'm sure I would have *freaked out.* But he never
lost his composure. A true leader in the face of tragedy.

On the way home, I mentioned this incident to someone I'd just met. He
recounted one time how he fell 35 feet and was paralyzed from the neck down
for six hours. For the next couple weeks, he wore a neck brace and suffered
an excruciating burning sensation whenever he was touched.

I hope that the cyclist on the trail that day also is as lucky and only
suffers temporary injuries.

"Pistof" <[email protected]> wrote in message
news:[email protected]...
> "Dorian Smith" <[email protected]> wrote in message
> news:[email protected]...
> > Any word on the strength of Kevlar forks? Yesterday I came upon an

> accident
> > on a local bike trail. The rider had struck a post and was paralyzed

from
> > the neck down. During the impact, his forks had snapped just below the
> > brakes. The wheel was still attached. I examined the severed part of the
> > forks and noted that they were cleanly broken.
> >
> > Not only did this accident firmly convince me to wear a helmet and ride
> > safely, but I'm now suspicious of non-metal materials. Should I be? The
> > rider said the bike was a two-year old Trek with Kevlar forks.

>
> That's horrible. Do you know it he'll be paralyzed for the rest of his
> life?
>
> Dave
>
>