Shimano RS chrome (RS12)

Shimano RS derailleur (RS12) main image

With the Shimano RS (RS12) the already venerable Skylark design took a couple of small steps forward. The cable clamp was mounted on a Centeron lever, allowing the derailleur to automatically compensate for the need to overshift. Perhaps more significantly the Centeron lever acted on the outer parallelogram plate - changing the geometry of the gear, as previously the cable clamp was attached to the front knuckle.

Despite these changes, the RS is a cheap, basic, tidy, design that is clearly a Shimano Skylark underneath.

  • Derailleur brands: Shimano
  • Categories: Shimano - from Skylark to world domination
  • Country: Japan
  • Date of introduction: 1981?
  • Date of this example: 1981 (two letter code FB)
  • Model no.: RS12
  • Weight: 290g including hanger plate
  • Maximum cog: 28 teeth
  • Total capacity: 28 teeth
  • Pulley centre to centre: 54mm
  • Index compatibility: friction
  • Chain width: 3/32”
  • Logic: top normal
  • B pivot: sprung
  • P pivot: sprung
  • Materials: steel
Shimano RS derailleur (RS12) additional image 01