This Bridgestone Klimatic was a tidied up child of the Bridgestone SMS Max. (both were manufactured by SunTour). The indexing cylinder below the derailleur has become a fraction of the size, although it still turns a cam that drives a roller that drives the parallelogram in the same basic way. The pulley cage on this long arm ‘GTL’ version is SunTour’s third generation ‘Tech’ double pivot design. Unlike the short arm version, the knuckles on the long arm version are aluminium. All very good, but by this time Shimano had established SIS and no one (except Bridgestone) was interested in SunTour’s cam based system. I believe that SunTour manufactured the Klimatic range exclusively for Bridgestone.

Interestingly the indexing mechanism means that the adjustment screws have been moved to the front of the derailleur (as on the original SunTour Competition). Long ago this design was abandoned because the screws tended to catch spray from the front wheel and rust solid - this would not be a problem with the plastic knuckles on the short arm version - but might be more entertaining with the aluminium knuckles on this example.


  1. Brand: Bridgestone, manufactured by SunTour

  2. My category: SunTour - Frank Berto and the curse of Duopar, SunTour  - indexing insanity

  3. Country: Japan

  4. Date of introduction: 1986?

  5. Date of this example: 1986 (two letter date code is CH)

  6. Model no: unknown

  7. Weight: 387g

  8. Maximum cog: 34 teeth?

  9. Total capacity: 40 teeth?

  10. Pulley centre to centre: 80mm

  11. Index compatibility: 6 speed?

  12. Chain width: 3/32”

  13. Logic: top normal

  14. Pivots: three pivots, rear unsprung and the other two sprung

  15. Material: aluminium knuckles, steel parallelogram plates and pulley cage plates, aluminium link plate.


Bridgestone Klimatic GTL