The early Shimano 600 derailleurs were revolutionary in a number of ways. They were part of a full groupset - a new phenomenon for a mid level price point, they were designed for Campagnolo drop-outs (gone was the homage to Simplex), and most important of all, they were well finished and looked ruthlessly composed and modern. I can well remember marvelling at the sheer glamour of mid-range bikes kitted out in the full 600 groupset - they looked so much better than their peers clad in a mishmash of Weinmann centre pulls, SR cranks and SunTour V series gears.

This example is a short pulley cage, black, version of the second generation which have 6100 model numbers. The distinguishing feature is that the ‘600’ on the outer parallelogram plate is in small script - I have never been able to detect if there were any more substantive differences.

All in all, a pretty damn fine derailleur - particularly in its short cage version, which gave a pleasant fluid gear change despite its lack of a slant parallelogram.

The 6100 series of Shimano’s 600 groupset was the first to sell in quantity in Britain. It feels like an old friend!

• Derailleur brands: Shimano
• Categories: Shimano - the Ultegra story, Shimano - the Deore XT story
• Country: Japan
• Date of introduction: 1976
• Date of this example: 1977 (two letter date code is BI)
• Model no.: 6100
• Weight: 231g
• Maximum cog: 28 teeth (Sutherland’s 6th edition)
• Total capacity: 28 teeth
• Pulley centre to centre: 46mm
• Index compatibility: friction
• Chain width: 3/32”
• Logic: top normal
• B pivot: sprung
• P pivot: sprung
• Materials: largely aluminium, steel pulley cage plates