It's nice having a friend who does a lot of paint restorations, because I get
to see a lot of bikes going through in various states of paintlessness.
Another friend, Bob, just recently got an integrated headset Bianchi from ebay
(that was in the shop) and was surprised when I said "it's a 1970" as he thought
it was a 1965. The serial number was 170 165 with the 170 smack in the middle
on the right side of the lug and the 165 on the left. The reasons I thought
this are: the 60s bikes have the serial number less separated, running across the
front of the seat lug, his bike has diamond reinforcements on the rear brake
bridge and works with a standard reach rear brake with no drop bolt. All of
the older Bianchis I have seen or owned (60s, not 50s), required a drop bolt
with a standard reach brake or a really long (Universal 51 type) rear caliper.
I had recently seen at the Cupertino Bike Shop 50th anniversary event (and am
going to photograph this bike for Dale's site) a Bianchi from what is
believed to be the last year of production of the integrated headset models. The
serial number begins with 172 xxx, corresponding to a 1972 date. Along with the
diamond reinforcement on the brake bridge, another interesting identifying
feature of these last bikes is the headset internals. These bikes use a headset
made by Campagnolo that is a different dimension than the earlier headsets with
the "V" races. The diameter of the pieces that insert into the lugs on the late
bikes is 32.1mm, the similar pieces on the earlier bikes are 32.8mm. This
came up because Ed Litton, the most excellent restorer in who's shop all this is
taking place, noticed that Bob's frame had a Campagnolo lower stack and a "V"
upper stack that had been ground down (very well done job) to fit the frame. I
have headset parts of both kinds and it never occurred to me they were
different, so I measured them.
The current state of confusion over Bianchi serial numbers is that the early
60s bikes start with 160xxx (for 1960 frames) and go through 165xxx (for 1965
frames) or so. With any luck, if all you Bianchisti out there use Dale's
serial number registry, this may become more clear. At some point serial numbers
started with 200xxx and go through at least 201xxx, before switching to 170xxx
for 70s bikes, finishing with 172xxx.
I welcome any and all contributions to knowledge on this subject.
Stevan Thomas
Alameda, CA