In my Raleigh Banana story
http://www.simonmason.karoo.net/page470.htm
The consensus was that the forks were buckled.
I just received this interesting e-mail from an engineer :
A comment about one of your photo captions: "This picture put up on
Usenet brought the unanimous conclusion that the front forks were
buckled." I must disagree with the unanimous conclusion. The front
fork has not buckled, but bent; most likely caused from an horizontal
impact on the front wheel. Why do I say that, you may ask. Well, for
two reasons. One, is because I am a structural engineer bent (sorry
about that!) on educating people on the distinction between "buckling"
and "bending". Buckling is an instability phenomenon and occurs
suddenly, as when you step on a beer can and suddenly its sides collapse
(load is applied perpendicular to deformation), while bending occurs
more gradually, in proportion to the load (load is in the same direction
of deformation). These explanations are very simplified, of course and
I am always willing to expound forth - but no one ever asks.
But the main reason is that because back in circa 1969, while cycling
from New York to Philadelphia with a friend of mine, I momentarily
looked back to spot my friend and I ran into a parked car while
traveling around 25 mph. My front wheel hit the car bumper square on
and I was ejected over the car, landing on my soft bottom a few feet
ahead of the car. I believe I must have equaled Beamer's broad jump in
Mexico City, and I was at sea level practically. I had not a scratch
nor any bruising or pain, I was just a little dazed to our amazement.
I picked up my bike to resume our trip and gave it a thorough inspection
and could not find anything wrong with it. That is, until I tried to
mount it: the front wheel would not straighten. The front tire was
touching the front diagonal tube of the frame. But everything looked
all right! It was only after we placed our bicycles side by side that
we realized that my front fork developed an extra bend - exactly where
your photo shows. But this bent was more severe, as the wheel was
displaced backwards at least 1", maybe almost 2". The front fork was
almost a perfect shallow "S" shape. The bends were perfectly and
absolutely symmetric, smooth as if carefully formed that way on purpose
and the paint did not even peel. The solution was to flip the wheel 180
degrees relative to the handlebar, and off we went on our trip after
being delayed less than one hour