Mike Kone wrote:
> Hi CR folks,
> I'm wondering if anyone has any definitive knowledge of early record rears with the sprung upper pivot? I just assumed they existed because a friend has one and another one hit about $600 on ebay about 6 months ago. In retrospect, these mean nothing if they are rare and exist soley because they were modified units that are mistaken for real production items.
> As further evidence,it turns out that my friends record with spring came off a bike that was a Spence Wolf machine - which is consitent with it being a modified version. There is a chance my friend might be able to bring it to the Cirque for analysis. (cut)
> I thought I generally knew about the older campy gran sports. I need help on this one. I figure it to be 1950's as it has the cable adjuster (That has a cast arm that causes it to set very far away from the body, different than all of my other G.S.) as compared to the cable stop. What is REALLY odd is the at the bolt for mounting it to the frame or in this case the hanger to mount it on the frame that does not have have a drop out hanger is aspring set up like the bottom end for piviting the pulleys. At first I thought someone had just been stupid and spaced out which side they assembled the spring on, but this has a very shallow coveron the back side also. That with the different castings tell me this is a different animal. Any Ideas? Thanks
Yes, it's a hotrodded part!
You take the top pivot of the Sport derailleur (intro'd 1952), which is sprung because it is a single pulley derailleur design, and you swap it out with the top pivot of the Gran Sport. (Remember the early Campagnolo drop out with the small hole just above the derailleur mounting hole? That's where the spring end goes.)
Then your Gran Sport has the equivalent of the Simplex parallelogram derailleur with the superior sprung upper pivot.
I don't know who did this mod first, but I know Spence Wolfe of Cupertino Bike did some conversions like this. Maybe in conjunction with his Alpine extended pulley cage conversion too.
Chuck Schmidt South Pasadena, Southern California