Originally Posted by
Amen
Think of it this way.
If you had to lift a weight using a pulley system twice, once with a super strong chain, the second time with a flexible peice of nylon, you will have a harder time lifting it with the nylon because you "wasting" energy on stretching the nylon.
So yes, stiffer frames are faster. Assuming all things equal you will probably gain a tiny amount of performance. Not noticeable of course.
Next topic.
Your analogy was definately not worth bumping a one and a half month old thread. Once the nylon is stretched, the effect should be the same on pulling(it won't continue stretching as you pull). Your analogy would be better if you said there is a weight you are pulling in opposite directions with your hands. Additionally, when a frame flexes in one direction, as it returns it should "give back" to the other direction. Either way these analogies do nothing to prove the topic.
The only time anyone can say "next topic" is when they've built exact same dimensional bikes with greatly varied stiffness qualities and power testing is done at actual riding speeds and conditions.
My thought is we would find stiffness numbers moot.