Geometry primer
 

I see a lot of references to frame geometry -- aggressive, relaxed, mountain, road, sloping top tube, chainstay length, head-tube length etc -- and would appreciate if someone could give a quick primer on the significance of various geometry-related items and how they make a difference for various types of riding.

Its all about the actual Numbers Tube lengths and Joint angles

in case of seat tube inclination 68 to 75 degrees makes a world of difference..

if you hire a frame built its some of the choices..
sit up and cruise, to down in a racing tuck low bend-over posture

there are lots of charts by various bike companies on their own specifics.

DIY web surf away on those..

fiets, I think you scared him off!

Could have made him go thru tuition billing before letting him into an amphitheater like, class of 300.

Here are three minor points:

- Some of it is to do with getting you in position on the bike, not fit per se, but stuff like lowering wind resistance and therefore needing further adjustments to have a good biomechanical position since now you are leaning way forward.

- Some of it has to do with the bike's relationship to the road, better climbing, more agile, etc...

- And some of it has to do with externals like style, durable misconceptions, nostalgia, marketing, or the performance needs of athletes who are in no way similar to us.