So much for avoiding the flame war.
Originally Posted by
lsberrios1
I think it makes sense if you say, "try running in sand and then running in concrete" You will probably be faster off the line on concrete than sand.....
That's not a relevant comparison.
1) When you deflect the frame, the returned energy still winds up going to the drivetrain. (Yes, I know, it's counter-intuitive.) The only losses are to friction, and that's negligible.
2) No one has produced any solid evidence to settle the matter. In comparison, we have seen real-world tests which demonstrate the performance advantages of aerodynamic frames, wheels / spokes / rims, helmets, helmet covers, foot covers, skinsuits, etc. Even those often-tiny differences have been tested and quantified.
The advantages of a stiffer frame are not in power transmission; it's in improved handling, ride feel, and keeping the wheels on track. That is important, but it's also not going to be any different when comparing a BB that deflects 0.3mm vs 0.5mm.