The Maruishi IC is a SunTour Mighty Click (2700) index system derailleur branded up for Maruishi. The letters 'IC' stand for 'Ideal Change' and continue a naming pattern set by Maruishi's 'PC', 'Perfect Change' electronic system.

There is one small, and perplexing, difference between the Maruishi IC and the contemporary SunTour Mighty Click (2700) - the cable clamp washers are different. Why SunTour changed this tiny component from one very acceptable design to another equally acceptable design is a mystery.

I have not been able to find much information about the Maruishi IC system in adverts or catalogues, except that it was used on teenager's 'Flasher' bikes. Hideki Sasaki seems to claim that the Maruishi IC derailleur was paired with a front-freewheel chainset, imitating Shimano's 1977 'FF' front freewheel components. This is certainly possible, as Maruishi had a number of its own front freewheel chainsets, the most famous of which simulated furiously spinning turbine blades - perfect for severing the fingers of teenage riders in that inevitable accident.

I believe that this is a later version of a Maruishi IC. The outer parallelogram plate is decorated with a strange bulge. This may be to allow more room for the cable - or, of couse, it could be an 'air scoop' relating to that turbine chainset.

• Derailleur brands: Maruishi, manufactured by SunTour
• Country: Japan
• Date of introduction: 1980?
• Date of this example: 1980 (two letter date code is WE)
• Model no.: 4000 (according to Hideki Sasaki)
• Weight: 384g including hanger plate
• Maximum cog: 30 teeth
• Total capacity: 16 teeth (Source: SunTour assuming 26mm dropout) or 22 teeth (Sutherland’s 6th edition)
• Pulley centre to centre: 59mm
• Index compatibility: 5 speed
• Chain width: 3/32”
• Logic: top normal
• B pivot: unsprung
• P pivot: sprung
• Materials: mainly steel with an aluminium rear knuckle

Ref. 1857