Measuring frame angles, head tube and seat tube specifically.


I've found and measured frames with angles ranging from 69 degrees up to 78 degrees. These angles have a huge impact on frame fit and handling behavior, and hugely impact which fit parameters (saddle fore/aft, handlebar style/reach and stem extension length in particular) will be needed to get the best setup for a particular rider.

Without having reliable frame angle and dimensional data to rely on, getting a rider fitted to a bike can be more "black art" than science.