Originally Posted by
AzTallRider
It's kind of like the Max Heart Rate formula. Average a big population, and it works, but that doesn't mean it works, for any specific individual, to be at KOPS. When you say relative to KOPS, then of course that makes sense, as that could describe a wide range of saddle positions
Actually, he was pushing himself back, then sliding forward until he was about to fall off, then pushing himself back. He was asked about it, and attributed it to a minor fit issue that was later corrected.
TT geometry doesn't just slide the rider forward, it rotates the entire body, both bringing it forward and tilting it into an agressive aero position. How far forward is limited by UCI rules, at least for those racing in UCI events, and there are saddles (e.g., ISM) designed to get the rider as far forward as possible without violating UCI rules.
I couldn't remember if it was forwards or back.
I don't see the relationship to a HR formula. People have been adjusting the sitting position relative to the spindle and not necessarily over the spindle to achieve different ends forever. It's well recognized that exactly where you adjust your knee relative to the spindle is just a guess until you get some experience. The HR formula never changes no matter the experience factor. The age variation is bogus as well.
When you rotate the seat tube forward, you do rotate the entire body forward, just like when you adjust the knee forward by moving the seat forward. The rider goes forward relative to the bb/spindel and his knees move forward of his original kos relative position in both cases. The only difference I can see is that while in both instances the seat height changes, the change is in opposite directions.
You can (could?) get seat posts wth set-forward instead of set-back to accomplish the same thing as rotating the seat tube forward.
A steeper seat tube angle also moves the handlebars further away from the rider IF he keeps his original position relative to the bb/pedal spindle. Most folks ignore that when fitting a bike.
It's all related and it's all just adjusting the default or starting sitting position relative to the BB to emphasize different factors.
Al