Here's an old posting from the archives:
Subject: [CR]Campagnolo 130mm seat post Date: Mon, 17 Dec 2001 23:14:20 -0800 From: Chuck Schmidt <chuckschmidt@earthlink.net> To: classicrendezvous@bikelist.org
Pete Geurds wrote:
>
> Campy seatposts used to come in 130mm and 180mm lengths.
> I'm pretty sure I could not have used a 130mm post on my 25.5" Raleighs!
> When I saw that in the catalog I wondered who was using them.
Here's my explanation:
The Campagnolo 130mm micro-adjust Record seat post came out in 1956 before the advent of plastic saddles. Leather saddles like the Brooks B.17 have very tall frames measuring 70mm from the rails to the top of the saddle in the middle. Plastic saddles (intro'd around 1960) typically measure 45mm or so from the rails to top of the saddle.
If you add 130mm for the short seatpost to the 70mm for the leather saddle you get a total of 200mm. If you add 180mm for the long seatpost to the 45mm for the plastic saddle you get a total of 225mm, only 25mm (roughly one inch) taller.
One reason the frame you rode in 1950 measured larger than the frame you rode in 1985 (before the current mt. bike seat post craze) would be the low bottom bracket and slack seat tube angle that would increase the seat tube dimension. The stand-over height of the top tube would be the same for the 1950 bike and the 1985 bike, but the BB would be closer to the ground, hence the "larger" 1950 frame.
Chuck Schmidt South Pasadena, Southern California http://www.velo-retro.com (Velo Rendezvous info, t-shirts, reprints & Campagnolo Timeline)
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