PANTOGRAFATA SEATPOST VERSIONS
Soon after I posted my first pics of the bike, Ken Denny wrote to tell me that my seat post was a later version of the Pantografata seat post and therefore it could not have been original to the frame. I wanted to get to the bottom of this, so I decided to do some research.
I've looked at a bunch of photos and corresponded with several people, and this is the theory that I have come up with:
There were two generations of the Pantografata style seat post. The first generation, from 1973, is distinguished by having longer and narrower fluting than the second generation posts. I don't know when the second gen posts would have been introduced, but I assume it was around 1975.
The first gen posts came in two versions, standard (180mm) and short (150mm). The two versions have essentially the same pantographic design, with the main difference being that the standard posts have longer fluting than the short posts. The obvious reason for having the two versions was to accommodate tall and short frames.
The pantographic design of the second generation posts is slightly different from the first generation. The second gen posts have shorter and slightly wider flutes. At this point it appears that second gen posts also came in two versions, one for taller frames and one for shorter ones. But unlike the first gen posts, both versions of the second gen use standard length posts - the only difference between the standard and short second gen posts is the length of their flutes.
The following photos show both of the first generation versions. As you can see, the pantographic design is consistent, but the short version has shorter flutes than the standard version.
In the photos below, the short post came from a 74 bike, and the standard post from a 72 bike. My thanks to Brad Stockwell for these three great photos. (And I hope to be able to thank Charles Andrews as well, soon, very soon, for a hiqh-quality scan of his Pantografa brochure .)
Below is my seat post, which is a second generation post. Notice that the diamonds are centered along the length of the blue and green flutes, which is different from the first gen posts, which have the diamonds and the club higher up, closer to the top of the post.
In the photo below you can see another difference: the three sets of flutes above and below the club (the yellow, black and red flutes), are the same length above as well as below the club. The first gen posts always have the flutes below the club longer than the flutes above the club.
The seat post below belongs to Joe Bell. You can see that the diamonds and the club are centered in relation to the flutes. You can also see that the flutes above and below the club are equal in length, which is the exact same pantographic design as on my seat post, so Joe's post is also a second gen post. On Joe's post, however, the flutes are longer than mine, so it appears that Joe's post was intended for taller frames, while mine was intended for smaller frames. BUT, they are both standard (180mm) posts!
It thus appears that in the second generation of Pantografata posts, both the standard and the short versions were 180mm, and only the length of the fluting varied. It may be that "shorty" posts started to fall out of favor by then (probably around 1975), at least with Colnago.
In conclusion (at least for now - although things may change if "new evidence" is discovered), I believe my seat post is a second generation, short version of the Pantografata style of posts. (By the way, if you have a standard/long version and want to trade, let me know.)
Thanks for looking and if you have any input, please let me know (and if you have a Super Pantografata, join the Registry).
My thanks to Ken Denny for alerting me early on to this issue.