Hi,
I can understand geometry, but don't know much about bikes, and how their geometry is designed. Here are a few links that actually say something. (Most links I looked at just talked about geometry without describing what it was.)
In the link below, under the item "angles. Sheldon Brown states that the more vertical the vertical posts are, the harsher the ride, but the more quick ly manuverable the bicycle.
http://sheldonbrown.com/gloss_an-z.html#angle
The article below describes how geometry acts to produce the steering characteristics of a bicycle.
http://www.phred.org/~josh/bike/trail.html
I haven't read these entirely yet. I see that I have stayed up WAY too late, once again!
BTW if anyone finds an article that explains this subject in detail, but is incomprehensible, I will try to make sense out of it for this forum.
Mary
Mary