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PostPosted: Wed Dec 26, 2012 10:54 pm 
Old School Grand Master
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Joined: Fri Oct 14, 2011 8:41 pm
Posts: 9221
Location: Cumbria
I was comparing Campag to the Huret etc that came with the Raleigh 10 speeds I had to set up. First thing to do with them was to take a metal bar and straighten the steel double chainwheels.......if they were too wayward we would claim on the 5-star dealer warranty LOL

I have had a look at a first gen Shimano mech from the mid 70's and at the front it's 12mm, in the middle it's 10 mm and at the back 15mm. The spacer is 10mm wide.

Torqueless is dead right in that a short wheelbase accentuates the chain angle :( BITD if that was a problem we would expand the front mech cage with a pair of pliers.........slot the pliers in narrow side into the cage itself and twist the cage open. Dirty trick but not a lot else to do :( No point in putting a larger spacer in as the usual rings were 52/42 so in the small ring the chain was not that near to the spacer...

Endless fiddling while riding is the order of the day :)

Even that didn't work if you were a big lad as the bottom bracket swayed from side to side knocking the mech into the chainline...........happy days :D


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PostPosted: Thu Dec 27, 2012 1:30 pm 
Retro Guru
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Joined: Tue Jul 20, 2010 8:22 am
Posts: 2173
Location: Warks
torqueless wrote:
Early Campag Record were notoriously narrow

Fair enough.. that's before my time! The only reference I have to hand is a mid 80s Nuovo Gransport. Distance between insides of cage plates: Fore.. 10mm. Aft.. (widest part, just before the outer plate bends in to meet the spacer).. 12mm. The spacer itself is about 8mm.

ps i have an old Bertin with friction shift,

Is it the same model of front changer?.. and how long are the chainstays, compared to this bike?

Re Bertin: No it's a Shim arabesque... can't compare chain stay length cos it's at the girlies house...
On this bike ( Mattolini ): the distance from the centre crank to centre rear QR is 422 mm

geometry doesn't look too steep re clearance from wheel to seat tube?

 Post subject:
PostPosted: Thu Dec 27, 2012 2:42 pm 
Retro Guru
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Joined: Mon Sep 24, 2012 9:10 pm
Posts: 945
Both bikes, Bertin and Mattolini, in your photostream seem to have racing geometry, with chainstays in the 16 1/4"-16 1/2" ballpark, (excuse my imperial) so I'd say that that wouldn't be a factor in this case... i.e. It's a constant. So the variable is the width of the cage, which seems to be confirmed by Midlife's measurements..

But.. you know.. I'm measuring an 80s Gransport, Midlife is measuring a 70s Dura-ace? AFAIK you are best placed to compare your respective cages.. However distant your girl's gaff seems to be, chances are you are much closer to it than us!... :)

(Edit, after a bit of thought) Chain width, cage width, chainstay length, seat tube angle... If one bike has narrower chain, wider cage, longer stays, and more upright seat tube, that could combine to make for a lot less 'trimming' being necessary, however insignificant any one of those four factors appears to be, taken in isolation?

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