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Old 06-15-20, 05:33 AM
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Bikes: '73 Bottecchia Giro d'Italia, '83 Colnago Superissimo, '84 Trek 610, '84 Trek 760, '88 Pinarello Veneto, '88 De Rosa Pro, '89 Pinarello Montello, '94 Burley Duet, 97 Specialized RockHopper, 2010 Langster, Tern Link D8

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OK, don't know if anyone is still following this thread. I am updating just for my own record of events.
Started a thread on the FD issue on the Mechanics Forum here.

Looks like I bought a FD for a triple crank. It does not help me understand why the pivot distance is greater. Well maybe it does.
Since the distince of travel is greater for a triple, the pivots are extended to increase the range. When placed on a frame with a double crank, the position of the outer ring is equivalent to the middle ring on a triple. If the 53t was in a position from the center line of the frame equivalent to a triple, the cage would clear.

Why? because the cage moves in a vector that is not 90* from the hanger slot , but less than 90* so the cage is closer to the rings as it extends from the inner to the outer ring. Looking from the front, it moves to the west-north-west from the small ring.
I will have to find a braze on for a double in my stash. Might be a Superbe Pro until I find a reasonable priced Record 10V RD.

BTW. the Chorus RD on the Pinarello measures 18mm between the pivots. The FD in question has a distance of 23mm.

Just read on Sheldon that if an interference occurs with a large chain ring, grind off the bottom of the cage to clear as needed. Do I want to do that? Should I just sell what I have and get what I need?
Bikes don't stand alone. They are two tired.

Last edited by SJX426; 06-15-20 at 05:38 AM.
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