Charles wrote: I posted what I did because I experienced a distinct improvement in sprinting and climbing on the Rensho, over the typical early 70s Colnago Super, which tends to have thinner seat-stays, and slacker angles than the Rensho.
To which I have taken too long to respond: The thinner seat stays have nothing to do with the ride or performance on the bike. They are in compression so on a caliper brake bike, the wall thickness and or diameter of the seat stays is almost irrelevant. I think you are onto something regarding the seat angle though. I wouldn't argue that a steeper seat angle across the board makes for faster performances but for some people it does. You must be one of them.