Old 02-25-12, 02:15 PM
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onespeedbiker
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Originally Posted by JohnDThompson View Post
If you're willing to step out of the Nuovo/Super Record era, by the late 80s Campy was making an off-road group that included an elegant long-cage derailleur that incorporated the Simplex sprung upper pivot and Shimano dropped parallelogram (as did the original Rally) but also the SunTour slant parallelogram that allowed the upper pulley to better track the freewheel cogs:

The original Rally was not a slant parallelogram; this a very common misnomer. There is a difference between a drop parallelogram and slant parallelogram. Suntour had a closely guarded patent on the slant parrellegram from 1964 to 1984 and no other derailleurs utilized the slant parallelogram design except Suntour. Campy didn't even get in the game until 1988. The Icarus derailleur (1992) you show is indeed a slant parallelogram. Yes I know that Classic Rendezvous says that the Rally was a slant parallelogram
"The first edition Rally was controversial in Italy as the slant parallogram style seemed to mimic Japanese derailleur design,
which was unacceptable to many Italians!" "1980s: new Rally with a different body, no longer slant parallelogram (less effective design)"
but they are wrong. Compare the Icarus to the 2 3450 Rallys I am posting. A drop parallelogram lowers the derailleur and turns it sideways, but as with all straight parallelograms the face if straight and not canted up or down. In order to incorporate the slant parallelogram, the parallelogram must be slanted downward, so the face plate of the derailleur is canted upward as with the Icarus. There is a little bit more information on this in this post http://forums.roadbikereview.com/ret...am-254759.html
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Last edited by onespeedbiker; 02-25-12 at 02:19 PM.
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