This is an early example of a chainstay mounting SunTour Wide derailleur manufactured for SunTour by a company called Iwai. The small enamel badge riveted on just below the frame mounting screws says ‘SunTour Iwai’.

The underlying design remains a version of any number of French designs from the 1930’s (see the Super Champion/Osgear Grand Sport) . As ever, though, this Suntour is a well executed example of the genre. The cutaway mounting plate is particularly stylish.

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• Derailleur brands: SunTour manufactured by Iwai
• Categories: SunTour - pull-chain models
• Country: Japan
• Date of introduction: 1955?
• Date of this example: unknown
• Model no.: unknown
• Weight: 316g including integral mounting plate but excluding external chain tension spring and chainstay clamp.
• Maximum cog: 28 teeth?
• Total capacity: 28 teeth?
• Pulley centre to centre: 70mm
• Index compatibility: friction
• Chain width: 1/8”?
• Logic: low normal
• B pivot: none
• P pivot: sprung
• Materials: steel