A customer brought an (I think) early 1960's Bianchi
frame to me seeking a seatpost. There is a sleeve
reaching from the top of the seat lug to @ 10-12mm
below the bottom of the slot inside the seat tube.
Inside diameter of this sleeve is 25mm. Was this a
repair, or are all Bianchi frames of this vintage
constructed in this way? I owned a Bianchi track bike
many years ago and don't remember anything so unusual
about how the seat post fit.