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.

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1. •Brand: Shimano
   

2. •My category: Shimano - weirdness
   

3. •Country: Japan
   

4. •Date of introduction: 1986
   

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

6. •Model no: L525
   

7. •Weight: 264g
   

8. •Maximum cog: 28 teeth (Sutherland’s 6th edition)
   

9. •Total capacity: 28 teeth (Sutherland’s 6th edition)
   

10. •Pulley centre to centre: 55mm
    

11. •Index compatibility: 6 speed (Sutherland’s 6th edition says the SS version is SIS compatible)
    

12. •Chain width: 3/32”
    

13. •Logic: top normal
    

14. •Pivots: two sprung pivots
    

15. •Material: aluminium knuckles and outer parallelogram plate, steel pulley cage and inner parallelogram plate.
    

0307/K