Shimano Light Action (L525 SS)

Shimano Light Action derailleur (L525 SS) main image

Shimano’s Light Action design involved mounting the cable clamp bolt on a short lever that was independantly sprung, allowing some ‘give’ before the parallelogram was shifted. It was the direct descendant of the ‘cable saver’ on the Shimano Lark and Eagle designs.

I liked it a lot. Combined with well made, affordable, slant parallelogram derailleurs it gave a slick, fluid shift - tangibly nicer than SunTour’s comparably priced offerings of the time.

This example is a short cage version of the best of the Light Action range - with a satin finish aluminium outer parallelogram plate.

  • Derailleur brands: Shimano
  • Categories: Shimano - weirdness
  • Country: Japan
  • Date of introduction: 1986
  • Date of this example: 1986 (two letter date code is KD)
  • Model no.: L525
  • Weight: 264g
  • Maximum cog: 28 teeth (Sutherland’s 6th edition)
  • Total capacity: 28 teeth (Sutherland’s 6th edition)
  • Pulley centre to centre: 55mm
  • Index compatibility: 6 speed (Sutherland’s 6th edition says the SS version is SIS compatible)
  • Chain width: 3/32”
  • Logic: top normal
  • B pivot: sprung
  • P pivot: sprung
  • Materials: aluminium knuckles and outer parallelogram plate, steel pulley cage and inner parallelogram plate.
Shimano Light Action derailleur (L525 SS) additional image 01

Browse associated documents.

Shimano Bicycle System Components (1987) scan 25 of 28

Shimano Bicycle System Components (1987) scan 25 of 28

Shimano Bicycle System Components (1987) scan 25 thumbnail