Re: [CR] Down tube shifter position on large frames

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Date: Fri, 1 Dec 2000 07:56:17 -0800 (PST)
From: Morgan Groves <m_groves@yahoo.com>
Subject: Re: [CR] Down tube shifter position on large frames
To: classicrendezvous@bikelist.org


Combining a couple of recent threads: my second serious bike was an Atala 104 (I think). It was a 65cm frame with a top tube some 12 feet long--or so it seemed! In order to make it rideable, I had to find a stem with about a 1 inch extension to be able to reach the handlebars. I'm a tad over six feet (now shrinking), and my arm span is 6' 6", thanks to my primate ancestry, so I need a fairly long top tube, but the Atala was ridiculous! I would have liked to have seen the person for whom my Atala was sized properly, but I suspect he was traveling with a sideshow.

The bike had fairly unusual componentry as well--Gran Turismo rear derailleur, Valentino front, Nuovo Tipo hubs, and cheap Universal center-pull brakes. The frame was all Columbus, with chrome long point lugs, a nice white & red finish, and a beautiful head tube badge.

The Atala introduced me to the tendency of large frames to develop a shimmy on downhill and other high speed coasts--it became practically unmanageable coasting above 20 mph.

I replaced the downtube shifters with Sun Tour barcons, but the Gran Turismo didn't work much better. I only rode the bike about 2k miles, but I had to change to a Sun Tour derailleur as I remember. My next bike was a Bottecchia with a Campy Record (not NR) partial group. It was a better bike altogether, and it stayed in the family for several years. It, too had a tendency to shimmy, but it was always manageable. In 1975, I replaced it with the Bill Boston.

Morgan


--- Joseph Bender-Zanoni wrote:


> The problem here is that the optimum seat-handlebar
> relationship gets kind
> of fixed witin a narrow range. Now consider the
> headtube length for a big
> frame. Downtube shifters get awful far down on a
> bike with an eight or nine
> inch headtube. As Morgan points out, bar-cons, like
> stem shifters and
> brifters stay relative to the handlebars.
>
> I like bar-cons a lot too, especially with modern
> stiff and smooth cables
> and housing to give crisp shifting. This is one area
> where the retro
> approach was all wrong. Flexible coiled stainless
> housings plus serrated
> Campy bar-con cables are virtually unworkable.
>
> As a funny thought think about shifting a Campy Gran
> Turismo with the
> period Campy bar-cons, cables and housings. Ouch.
> Did anyone ever see a
> bike with that set-up? Lets up the ante- over what I
> vaguely remember is
> the the claimed range stamped on the Turismo of
> 36-54 and 14-34.
>
> Forgive my heretic tendencies as I praise Varsitys
> and castigate Campy in
> the same evening.
>
> Joe

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