Originally Posted by
Andrew R Stewart
I don't want to tell you what your frame design should be, more to see how others do things.
The front center is getting long, some feel that this should be balanced by a rear center (chain stay) length. As the frame size grows so does the seat's set back from the BB center. So tall size with short stays and long front center means more rearward weight center.
Seat set back is generally thought as the horizontal dimension from the tip of the seat to a vertical that bisects the BB. 3-8cm is a range that many find right.
I agree about wide tires being better often. And
What you say about the rear triangle makes sense. Looking at some manufacturers figures, they often use exactly the same chainstay length for all but the smallest frame sizes - I guess that is for production/cost reasons.
The chainstay length on the bike I am working from is 410mm and it handles real nice,. I have increased that to 418mm for clearence rather than balance. I am making quite a big frame so maybe I will increase it a bit further still.
The set back is 95mm on my drawing, I will check my other bikes as this seems a biy high going by your figures.
Thanks Andy, - these are the sorts of things I need to think about.