During the 1950s there were two big beasts in the Japanese derailleur market. Sanko dominated the market for short cage derailleurs for racing and utility bikes and SunTour were the kings of the long-cage derailleur for dedicated touring bikes.

But then, in 1963, SunTour started to import the highly affordable Huret Svelto into Japan in quantity. At around the same time SunTour launched its own, flat-plate, low-priced derailleur - the SunTour Skitter. Both were modern, parallelogram-based, short-cage models aimed squarely at utility bikes and junior racers. It was a threat that Sanko could not ignore.

And so we have the 1965 Sanko PF. It was highly derivative of the Huret Svelto, but with a number of intelligent tweaks. Most notably it had sensibly placed adjustment screws and inexpensive, but effective, pulley wheels with plain bearings. It also had clean branding and was finished to a high standard. It's a derailleur that is hard not to like.

However, I would, quietly, suspect that Sanko was not really set up to produce large volumes of cheap products (and may have lacked the ruthless corporate culture required to do so). Unfortunately the Sanko PF faded away when Sanko went out of business in the late 1960s.

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I believe that this example is an early Sanko PF from 1965, largely because it has a round guide pulley (with no teeth). It is surprisingly different from the 1966 version:

• The guide pulley is round, tooth-free and steel with a nylon bearing.
• The tension pulley is a plastic, toothed item with no dust caps.
• The hanger plate has a pointy outline. The dropout bolt has a round, counter-sunk head.
• The inner parallelogram plate rivets have their shop heads on the under-side.
• The cable clamp nut is an 8mm item. The cable clamp washer has a tab on the inside.
• The adjustment screws have simple round heads.

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• Derailleur brands: Sanko
• Country: Japan
• Date of introduction: 1965
• Date of this example: unknown
• Model no.: PF
• Weight: 261g including hanger plate
• Maximum cog: unknown
• Total capacity: unknown
• Pulley centre to centre: 44mm
• Index compatibility: friction
• Chain width: 3/32"
• Logic: top normal
• B pivot: unsprung
• P pivot: sprung
• Materials: largely steel

Ref. 2122