The Mighty Click was a mid-range indexed derailleur system introduced by SunTour in 1977. It was their first response to Shimano's Positron system, which had been introduced two years earlier.

The Mighty Click was a significant improvement over SunTour's previous friction-shifted derailleurs. It offered precise shifting with a positive click feel, making it much easier to shift gears quickly and smoothly. The Mighty Click also featured a slant parallelogram design, which helped to improve chain alignment and reduce wear.