DISRAELI DOCUMENTS

Sun-Bow

Japanese Patent S54-57737 main image Japanese Patent S54-57737 main image Japanese Patent S54-57737 main image


see also Japan's Bicycle Guide '56 1956

see also Japan's Bicycle Guide '56 1956

Japan's Bicycle Guide '56 - front cover thumbnail






see also New Cycling 05/1981 - Derailleur Collection

see also New Cycling 05/1981 - Derailleur Collection

  • Publisher: New Cycling
  • Date: May 1981
  • Derailleur brands: too numerous to list here
  • Derailleurs: too numerous to list here
New Cycling May 1981 - Derailleur Collection front cover thumbnail


see also Koyo Corporation - web site 2019

see also Koyo Corporation - web site 2019

  • Publisher: SY
  • Date: 2019
  • Derailleur brands: Sun-Bow, SY
  • Derailleurs: none
Koyo Corporation - web site thumbnail

Sun-Bow is the brand of a company called Yamashita Iron Works Ltd. based at No. 36, Sambocho 4-cho, Sakai, Osaka Prefecture, Japan. The evidence for this is:

  • The patents covering the Sunbow derailleur are assigned to Yamashita Iron Works Ltd. based at No. 36, Sambocho 4-cho, Sakai, Osaka Prefecture.
  • One Sun-Bow derailleur that I have acquired had a brown card label attached to it saying ‘Yamashita Iron Works Ltd. YA-100 Rear Derailleur’. This Sun-Bow also shares some small parts with an SY derailleur that I have.
  • Two independant Japanese derailleur enthusiasts have noted that 'Sun-Bow' sounds very like 'Sambocho' - part of the address above. This use of 'soundalike' words has some form in the naming of Japanese brands. It's a story that is just weird enough to be true.

Two further pieces of relevant information are that:

It seems clear that SY derailleurs and Sun-Bow derailleurs were produced by the same company.

It's possible that Yamashita Iron Works Ltd. of Sakai is still in business today. The story might, possibly, be:

  • The company was established in 1902 as the Yamashita Ground Metal Shop.
  • It started producing bicycle components in 1947.
  • In 1973 the company appears to have changed its name to Koyo Giken Company Ltd., and then to have established Koyo Engineering Company Ltd in 1980.
  • It also appears that, in 1973, it changed its main business to producing engineered parts for furniture - and so it is possible that its interest in bicycle components declined from this point.
  • Koyo Corporation exists to this day. It has a history page on its web site.

It is possible that Yamashita Iron Works Ltd. used the SY brand for designs that derived from Shimano models, and the Sun-Bow brand for designs that were inspired by SunTour. Or it is possible that the SY brand was used when the company was called Yamashita Iron Works Ltd., but when it changed its name to Koyo Giken Company Ltd. it also changed its brand to Sun-Bow. Both are guesses.