Simplex used the sprung top pivot on their very early derailleurs introduced in the early 1930s - these were single pulley derailleurs but Simplex continued with the sprung top pivot when they brought out their twin pulley derailleurs around 1946/7. Campy never had a sprung top pivot on the Gran Sport - it was their Sport single pulley derailleur that had a sprung top pivot. It is possible I gather to add a Gran Sport twin pulley cage to a Sport body to get a sprung top pivot Campagnolo gear...
Hilary Stone, Bristol, British Isles
Bob Freitas wrote:
>
> What ever Patent Suntour held it was enough for Campagnolo
> to retreat back to just putting a long cage onto an existing dérailleur.
> The design of both the Suntour and Rally had the body at a 9
> o'clock-3 o'clock orientation while Shimanos design was more of a 10
> o'clock-4 o'clock orientation.
> Jerry points out a Simplex advantage and since I an not
> that familiar with Simplex or its history, I have a question.
> When did Simplex first use an upper sprung pivot? I know that was a
> design feature of the original Campagnolo Gran Sport in the early 1950s.
> In regards to the Spense Wolf long arm conversions he also
> added the top pivot from the Campagnolo Sport dérailleur on some of them
> for an extreme hot rod touring unit . This long arm conversion was
> always used with a wide range front chairing configuration(always TA as
> I remember)
>
> BOB FREITAS
> who replaced 1.000,000 plastic Simplexes back in the day but not in
> MILL VALLEY, CA USA