The more I considered this issue the more it seems that there no longer is no good way to "equalize" frame measurements between bikes with single statistics.
Cannondale had been (and maybe still are) measuring their frames to the top of the seat tube... but this top point even on road bikes had extended considerably above the top of the top tube - and that was with level top tubes on their bikes. -- Measuring either c-c or c-t does not take into consideration the drop of the bottom bracket. -- Stand-over height also depends on the size of the tire in order to compare frames, so perhaps measuring with bare rims would be better... but how would we account for differences between time-trial bikes with 19 mm tubular tires and city/hybrid bikes with 38 mm clincher tires -- "stand-over height at center of top tube" would help compare compact frames with lowered rear triangles... but it does not account for the length of top tubes, so I would not know if I'm comparing a virtual 60 cm with a virtual 52 cm frame. And, even comparing "virtual" level top tubes as a basis could result in my comparing my 62 cm 1950s randonneur frameset with your current 52 cm Trek racing bike.
Anyone have an idea for a NEW perfect system?
Bob Hanson, Albuquerque, NM, USA
Here's a question that relates to framebuilding and history of the craft so I will beg forgiveness to cross-post to Framebuilders and CR list.
Does anyone have any insight about using c-c vs c-t dimensions for seat tubes lengths when describing a frame size. It seems that most Italian builders used c-t dimensions. Was there a reason for this vs c-c dimensions? Did it have to do with the build process itself in some way? Did these methods of measure change over time for any reason. Are there any build traditions where the top tube is not measured c-c as is the norm now?
Roman Stankus
Atlanta, Georgia
USA