DISRAELI GEARS

Sanko S3? (1951? version)

Sanko S (S3? 1951? version) main image

The Sanko S series dominated the small, but influential, derailleur market in Japan in the 1950s. These were very conventional low-normal, pull-chain, derailleurs that were extremely derivative of contemporary French designs. However, as with all Sanko products, they were very well made and excellently finished - possibly surpassing the Gallic originals.

The S series was made up of 9 models that were christened following a simple set of naming conventions:

  • If the letter is a single 'S', then it is a short cage derailleur, with a short main arm and a rigid (or non-existant) b-pivot.
  • If the letters are 'SR', then it is a short cage derailleur, with a short main arm and a sprung b-pivot.
  • If the letters are 'ST', then it is a long cage derailleur, with a long main arm and a sprung b-pivot.

  • If the number is '1', then it is an axle mounting derailleur with a hanger plate with a, conventional, forward-facing slot.
  • If the number is '2', then it is an axle mounting derailleur with a hanger plate with a rear-facing slot.
  • If the number is '3', then it is a derailleur that mounts on a braze-on beneath the chainstay.

So, for example, an 'SR3' would be a short cage derailleur, with a short main arm, a sprung b-pivot and a mounting under the chainstay. You can see a full listing in Sanko's April 1964 advert in New Cycling.

All S series derailleurs shared the same sliding rod mechanism, although different rod lengths were used for 3, 4 and 5 speed variants. I believe that all S series models could also handle both 1/8" and 3/32" chain.


I believe that this is an early and well-used example of a Sanko S3. It has the following features:

  • It has no b-pivot. The distance from the mounting to the sliding rod is quite small. Also the pulley cage, at 49mm, is short. All of this makes it an 'S' model.
  • It mounts below the chainstay - making it a '3' model.
  • The tension pulley is steel and runs on ball-bearings.

The cable stop on this derailleur does not look to be original (at least to me).


  • Derailleur brands: Sanko
  • Country: Japan
  • Date of introduction: 1951?
  • Date of this example: unknown
  • Model no.: S3?
  • Weight: 265g
  • Maximum cog: unknown
  • Total capacity: unknown
  • Pulley centre to centre: 49mm
  • Index compatibility: friction
  • Chain width: 3/32" and 1/8”
  • Logic: low normal
  • B pivot: none
  • P pivot: sprung
  • Materials: largely steel
Sanko S (S3? 1951? version) additional image 01
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Sanko S (S3? 1951? version) additional image 10
Sanko S (S3? 1951? version) additional image 11
Sanko S (S3? 1951? version) additional image 12
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Sanko S (S3? 1951? version) additional image 19
Sanko S (S3? 1951? version) additional image 20
Sanko S (S3? 1951? version) additional image 21

Browse associated documents.



New Cycling 01/1963 - Sanko ad

New Cycling 01/1963 - Sanko ad

New Cycling January 1963 - Sanko advert thumbnail


New Cycling 04/1963 - Sanko product range

New Cycling 04/1963 - Sanko product range

  • Publisher: New Cycling
  • Date: September 1963
  • Derailleur brands: Sanko
  • Derailleurs: too many to list here
New Cycling April 1963 - Sanko product range thumbnail


New Cycling 04/1964 - Sanko ad

New Cycling 04/1964 - Sanko ad

  • Publisher: New Cycling
  • Date: April 1964
  • Derailleur brands: Sanko
  • Derailleurs: too numerous to mention
New Cycling April 1964 - Sanko advert thumbnail