With the Crane, Shimano pulled out all the stops in an attempt to make a truly world-class derailleur. It was an all aluminium design with a dropped parallelogram - a world first. The finish was excellent with that anodised ‘glow’ that Campagnolo had perfected. The chromed parts were bright and polished. The pulleys had a two part bushing system so that bronze rotated on bronze. Even the springs seemed to have less of a tendency to lose their tension. All very classy.
Shimano were not backward in coming forward with the price - which set new records for a Japanese derailleur (even if it was still someway from Campagnolo’s extravagant pricing).
The only fly in the ointment was SunTour’s patent on the slant parallelogram. The Crane never changed gear quite as well as the much more lowly SunTour V series - despite Shimano’s puff about the efficacy of their ‘servo pantagraph’ design with its two sprung pivots.
This is a well-used example of the third generation of Crane with a steel cable clamp nut.
When I first got this example I thought that the extremely smooth-running steel pulley wheels were not original. However I have since seen four or five Cranes with exactly these pulley wheels - so I have now changed my mind. When Shimano introduced the Dura-Ace EX rear derailleur in 1978 it had pulley wheels with metal teeth - so I now think that Shimano experimented with these ideas on this generation of short cage Cranes. Both the steel cable clamp nut and the steel pulley wheels (and even the name Dura-Ace) could be the result of Shimano’s experience supplying the Crane to European professional racing teams - who might have been more interested in extreme durability than in feather-light weight.