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.