Dorian Smith said: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.
