Originally Posted by
Clyde1820
The implication being that when a frame flexes such that a rider's full energy is split between forward motion and downward flex, that upon un-flexing the frame returns that energy directly into forward motion. I suspect a spring could achieve this, aside from heat loss, as it's force is in-line with both compression and return. But a frame's flex would have to be spot-on equivalent and in-line, and occur at a time when the rider could actually use it, for the return, in order to recover that energy in the form of the forward motion that was previously lost. Wouldn't it?
I am unclear what you mean by "in line". But whatever vectors are relevant to the forces that the spring releases would be the same involved when it is compressed. I think that is a bit of a red herring, here.
As far as the timing, that would be part of the question I pose at the end of my post (the part that you did not quote).