So if you don't count weight, the only performance advantage that this era SR rear derailleur is this the ability to utilize these two additional teeth. Other than that, the parallelogram is exactly the same except for the new top and bottom plates; but all the parts of a NR and SR are interchangeable, because except for the outer plate, that are the same. But that didn't stop Campagnolo from claiming the SR as a huge improvement over the NR. The new top plate was supposed to be some exotic material , not just aluminum and the black coating used on the parallelogram ends and background for the Camapgnolo script was something other than common anodizing anodized. The shifting was touted as being extrodinary, but in reality is was exactly the same as the NR. Of course it does have titanium pivot bolts, but besides knocking off a few grams, they do nothing to increase performance.
But that is not say that being able to use a bigger cog or Titanium bolts are not wanted, but I never got the the new top plate. It was supposed to be new age, but it did not fit the rest of the components that were still the 1966 design. When Campy finally did upgrade to the short lived C-Record, they looked nothing like the graphics on SR rear derailleur (nor did any of the other SR components, which still followed the NR looks and designs.The first SR rear derailleur had a much more subdued look; pretty much a NR rear derailleur, only with the black parallelogram ends and instead of the "Campagnolo Nuovo Record" script on the top plate it said "Campagnolo Super Record".
My vintage Specialized Allez has a NR and I would like to mount this 1st generation SR rear derailleur except for two reasons. The first is they are quite rare and command top dollar and second it would not be period correct. All the other parts are 1984/85 NR and SR. So my plan was to combine the NR and SR rear derailleurs to make a defacto SR rear derailleur that looks like a NR rear derailleur. I have done this before with Nuovo Gran Sport rear derailleur with very positive results; again all the parts for all three of these derailleurs re interchangeable. To gather the parts I would need a SR inner cage and titanium pivot bolts. A while back I found a wrecked SR rear derailleur (see above) that had the lower titanium pivot bolt; it also had the inner cage, but that is being used on another derailleur on another bike right now. It was missing the upper pivot hanger bolt, which is not uncommon. These have a strange history as it was thought by many that the titanium hanger bolt was flexy and easily broken. There was probably little truth behind this, however it was common for racers to switch out the titanium hanger bolt for a NR steel bolt, which makes this bolt harder to find. I did however find one NOS at a web store and bought ot for much more than I should have. But then I had put this plan on hold until I found another SR inner cage. My patience paid off when I found someone selling the NOS SR inner cage on ebay; now I can finally put it all together.
What first needs to be done, is remove the cages off my NR rear derailleur. This is done by unscrewing the lower pivot.
Next I switch the pulleys from the NR outer cage to the SR outer cage; many refer to this as the inner cage or inner cage plate. However Campy situates parts starting from the frame, so the cage that holds the pulleys are referred to the inner cage and this cage, because it's farther away from the frame is the outer cage.
Next I attach the SR cage and pulleys
Next I load the spring, screw in the holding pin, and insert titanium upper pivot.
And viola! A stealthy SR rear derailleur that fits with the other components and is period correct. Not only that, I can now use a 28T freewheel if the mood takes me..
