Originally Posted by
PromptCritical
How does changing the seat angle and so forth change the handling and ride?
When designing a frame, it is necessary to prioritize what is important and compromise on what less so. For example some cyclists that are older, fatter and less flexible can no longer ride in the position that makes them most efficient. They are leaning over too far and putting too much weight on the hands, arms while trying to support their upper body. The solution is not difficult design frame wise. And that is to slide your butt back until your weight is balanced over the pedals and - like magic - you no longer strain to hold up your upper body. Of course this more upright position makes you less aerodynamic. US bicycles with drop handlebars are not designed for this situation. There is a zillion go fast bicycles in all materials that are designed with speed as a priority. They are not designed with a shallower seat angle (maybe 71º) to sit more comfortably upright. Because then you will run into toe clearance issues. And so the compromises to best handling begins. That might include smaller wheels or being more conscience of keeping your foot out of the front wheel when turning. For many people as they age, they will find that if they are not comfortable riding, they just won't ride so "how does the bike handle" becomes a non-issue. It is possible to design a frame with a shallower seat and - as a consequence - swallow head angle that rides okay. The alternative is to lose 50 or more pounds or become younger so you can go back to riding the bikes of your youth.
Lots of my framebuilding class students have retired and designed their frames for a more upright position and as a result continue to enjoy cycling (maybe at a slower pace). And by the way, it is not hard to figure out a comfy bike position. I have several fitting bikes (I've provided a schematic to a DIY one on this forum) and they don't need bells and whistles to provide trustworthy results. It is the guys/gals trying to shave a few seconds off of their results that are the bigger challenge. They will go to a store with one of the latest fitting bikes that are computer controlled with video feedback to make sure they are buying the right carbon bike.