The SunTour SX-100 is the SunTour S-1 redesigned so that it fits to a drop-out and does not need any special fittings on the chainstay. The SX-100 also has the indexing in the lever (usually a twist grip), not in the derailleur. The pulley cage is very short, as this gear is aimed at commuter and utility bikes with a single chainwheel.

It retains the somewhat elegant the horizontal parallelogram, but the mounting has become gross. This example has a Japanese-style ‘hanger’ with a rear facing slot.


  1. Brand: SunTour

  2. My category: SunTour  - indexing insanity

  3. Country: Japan

  4. Date of introduction: 1993

  5. Date of this example: 1994 (two letter date code is KA)

  6. Model no: SX-100

  7. Weight: 362g including hanger plate

  8. Maximum cog: 28 teeth?

  9. Total capacity: 26 teeth?

  10. Pulley centre to centre: 43mm

  11. Index compatibility: 5 speed?

  12. Chain width: 3/32”

  13. Material: largely steel, with a plastic rear knuckle and inner pulley cage plate


SunTour SX-100