Originally Posted by
RobbieTunes
Centurion measured funny, but basically, from the c-bb to the t-top tube, on the Ironman frames. They actually called it "to the lowest part of the scallop on the side of seat lug." Visually, this is about the same as the top of the top tube.
i see.. essentially "square". thanks as always for the reply robbie, easy way to remember it.
as for the quoted text.. it is interesting how centurion measured ironman and it seems other models of their bikes. i'm accustomed to taking the length from center of bb to center of where the seat and tt meet.. but always came up with a odd number like 51cm or 53cm. mystery solved lol.