The Eagle was Shimano’s attempt to wrest control of their brand back from Schwinn - at the time the most powerful bicycle manufacturer in the world. The Eagle met all Schwinn’s requirements, particularly the bashguard and the ‘cable saver’ sprung cable clamp, but it was Shimano’s own model.

This, 1971, style is branded more prominently than the earlier styles, with the word Shimano on the outer parallelogram plate. This example is a SS version with a standard length pulley cage.

Despite its horrendous weight (the bashguard is a serious piece of steel) the Shimano Eagle sold in vast quantities.

• Derailleur brands: Shimano
• Categories: Shimano - from Skylark to world domination
• Country: Japan
• Date of introduction: 1971
• Date of this example: unknown (no two letter date code, and has ‘3.3.3.’ marking on pulleys)
• Model no.: D310 or 52506001
• Weight: 379g 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 (and plenty of it)