Without getting into the testing methodology, the conclusions on the web site cited below are in my opinion useless.
The author claims there is no downside to a frame that is too stiff. That in my opinion is just plain wrong. Again, a Raleigh 3sp is super stiff, but dead. A frame must be neither too stiff or too flexible. It must have flex characteristics that enhance the riders pedal stroke without causing a sub-optimal amount of additional body motion.
Without getting drawn back into discussion that is in the archives - remember that frames DO NOT absorb significant amounts of energy - they are big springs.
The author of the frame flex tests and discussion cited below seems to have missed this important point.
Mike Kone in Boulder CO
> You might want to start at Sheldon's archive of Damon Rinard's bike
\r?\n> tech site.
\r?\n> Almost all the tests include frames from the pre-'83 time period or at
\r?\n> least a "KOF" frame of some kind.
\r?\n> Vancouver, B.C.
\r?\n> On Wednesday, Sep 28, 2005, at 13:20 US/Pacific, charles nighbor wrote:
\r?\n> > IN RIDE Issue Number 29 WINTER 2005 Page 139 there is a very
\r?\n> > interesting article on Frame Flex Testing with a Jig. Than on the
\r?\n> > following pages five frames are tested (Yes Modern new frames way past
\r?\n> > 1983 cut off but still tests results worth noting) and worth studying.
\r?\n> > When we discussed brazing materials silver versus brass and testing of
\r?\n> > them it brought this article to my mind. If you get a copy decide which
\r?\n> > one you prefer over the others. Than decide how it would affect ride.
\r?\n> > Then read how it did ride. See if you can go from test numbers to a
\r?\n> > correct interruption of results. I wonder just how much testing was
\r?\n> > ever
\r?\n> > done on steel lugged frames we all love and admire?
\r?\n> > Charles Nighbor
\r?\n> > Walnut Creek, CA