On the RIH I recently acquired the rear derailleur has toothless jockey and tension wheels. I have always associated this with derailleurs older than 1974 (looks like the 1951 Gran sport on CR web site). Would this have been a mod by the previous owner or was this configuration available in 1974? If it was a mod by the owner what is the advantage to the toothless jockey and tension wheel?
Marty Eison
Dallas, Texas