Originally Posted by
sovende
Perhaps it was the first day on the job for the person that did the brazing of the lower "pibb"! The one for the shifter band was oriented with the "lobes" up so they did the same for the lower one
. I'm wondering if the "heart" shape of the pibb was design specific for a proprietary set clamps that had corresponding cutouts
?
I can't say if this is what the pibb was designed for, but on my 1973 Nishiki it pairs perfectly with a Shimano 333 clamp (with the heart brazed on the other way around).
The clamp has seen better days. It was original equipment on this bike.