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.


  1. Brand: SunTour manufactured by Iwai

  2. My category: SunTour - pull-chain models

  3. Country: Japan

  4. Date of introduction: 1955?

  5. Date of this example: unknown

  6. Model no: unknown

  7. Weight: 316g including integral mounting plate but excluding external chain tension spring and chainstay clamp.

  8. Maximum cog: 28 teeth?

  9. Total capacity: 28 teeth?

  10. Pulley centre to centre: 70mm

  11. Index compatibility: friction

  12. Chain width: 1/8”?

  13. Logic: low normal

  14. Pivots: one sprung pivot

  15. Material: steel


SunTour Iwai Wide (1st style)