You are correct, this is in fact a horizonal, not a slant, parallelogram, and the fact that the SunTour patent was still in force when the Crane appeared is the reason the slant design was not used. Shimano never exactly quit making the Crane, they just changed the name to Dura-Ace. The first Dura-Ace grouppos in the 70's had Crane RD's and the RD's in this group for some reason continued to be marked "Crane" for several years after all the other components were marked "Dura-Ace". Eventually, about 1980 I think, Shimano began marking the derailleurs "Dura-Ace" for consistency with the rest of the group. My only guess about the naming is that Crane had become fairly well established as an aftermarket replacement for some pretty wretched European wide ratio derailleurs, like the Campy Gran Tourismo "boat anchor", and perhaps Shimano wanted to use the good reputation of the Crane in the aftermarket segment to attract buyers to the Dura-Ace grouppo.
Regards,
Jerry Moos
Thomas R. Adams, Jr. wrote:
> I managed to acquire a Shimano Crane GS the other day, and I'm wondering about the details of this shifter. This is the rear long cage model with the round holes drilled in the front chain pull arm. I remember them being standard equipment on older touring Schwinn Paramounts.
>
> It appears to be a horizontal parallelogram design, but not a slant parallelogram. Was this piece made before Suntour's patent expired? When did Shimano stop making Crane derailers.
>
> What size freewheel with the Crane GS handle, and how much chain will it wrap? Does anyone have any experiences to share about the derailer's performance?
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> Thanks
>
> Tom Adams, Kansas City