Originally Posted by bike eagle

It always seemed to me that fitting should be based on:

1. How far do I like my saddle (the part where my sitbones rest) from the BB?
2. How far behind the BB do I like that part of the saddle?
3. How much reach do I like from that part of the saddle to where I grip the bars? (For drop bars, that would be to the base of the hoods.)
4. How far below (or above) that part of the saddle do I want that part of the bars?

You really can't size a bike without knowing those four things.

For me, in inches, those four measurements are: 29, 10, 31, and zero.