Originally Posted by
Road Fan
For the fore-aft balance thing, I think there might be two things, but I think only one is significant. First is the weight on the front and rear wheels. Going back to the mid-1970s, "Bicycle Frames" by Joe Kossack says (p. 24) that British designers of the day generally tried to get 45% of the bike+rider weight on the front wheel and ... well, the rest on the rear. This is termed as being for good handling. I've never seen anything that says what goes wrong if you don't achieve this.
More significant for me is the location of my body center of gravity (CG) to the BB. When I ride no-handed I need either be planted on the saddle or to have my CG above the BB. If I don't I'll fall forward or backward. When I'm in the drops or deep into the hoods, I don't want too much pressure on my hands and especially if i have to remove my hands to negotiate a bump, scratch an itch, take a drink, or make clothing or anatomical adjustments, I don't want too much sensation of weight pulling me forward. I also like to lift my body, sometimes including my hands, off of the contact points to negotiate bumps (no, I do not know how to bunny hop). That body weight distribution is managed by moving the saddle back relative to the BB, either by sliding the saddle along the rails or getting a seatpost with more setback. Obviously, KOPS is not a significant part of this beyond being a rough philosophy. I near always end up with my knee significantly (1 to 2 cm) behind the pedal spindle.
Bunny hopping is totally worth learning how to do. The downside of it is that it takes time and therefore distance to set up, Timing is also critical. You don't want your rear wheel to hit the object at the end of the bounce, the worst possible outcome. That said, it's fun to do and a worthwhile skill to develop. Nothing to do with weight balance of course. On my 52cm road bike, the seat tube has been made more steep, which I counteract by using a special large setback post, just as you say. IOW, the seatpost angle gained me nothing. Stupid. The only possible gain is that my seatstays are slightly longer than they would be otherwise, which may give me a slightly smoother ride in the back. I am grateful that the BB is where it is, no toe overlap.