Just as I suspected frame design has been to a great degree by seat of the pants engineering. Look at comments we get. Some are drawn from what seems logical concussions but in fact nothing to back them up other than a ride on a certain bike. The ride and how it feel parts is a good indicator of how frame functions but the reason given for that function may be completely wrong. Then reading other comments from people in Physics and related fields and articles on actual testing are much more relevant and leave behind ''seat of the pants engineering' Just an observation. Charles Nighbor, Architect King of Observations and wrong concussions Walnut Creek, CA