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

see also Japanese Patent # S54-57737 1977

see also Japanese Patent # S54-57737 1977

Japanese Patent S54-57737 thumbnail

Sun-Bow - YA-100 label 1977?

Sun-Bow - YA-100 label 1977?

Sun-Bow YA-100 label 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

I shall attempt to mask the poverty of my knowledge about Sun-Bow, by remarking on the strange tendency for the Sun to pop up in the names of derailleur brands. Sun-Bow, SunRace, SunRun, SunTour and I think I have even seen Golden Sun, Sunrise and Sunset - what is it all about? Is this solar fixation common to many products from the Far East - or is it peculiar to derailleurs? Why doesn’t the Moon get a look in? Mars and Venus make an appearance but what about Jupiter, Pluto or even Uranus?

The little that I do know about Sun-Bow is that one derailleur that I acquired had a brown card label attached to it saying ‘Yamashita Iron Works Ltd. YA-100 Rear Derailleur’. Coincidentally, the only S.Y. derailleur that I have seen has the words ‘Yamashita Japan’ stamped on its inside parallelogram plate. It also shares some small parts with Sun-Bow derailleurs.

Based on these tiny crumbs of evidence, my pitiful researches on Google have thrown up two possible companies who may possibly have manufactured the Sun-Bow brand.

  • The first of these is the Yamashita Manufacturing Company based in Sakai, Japan the home of Shimano and SunTour. This company was established in 1902 as the Yamashita Ground Metal Shop (!?) and 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 the manufacture of bicycle components died out at this point. Koyo Corporation exists to this day. It has a history page on its web site.
  • A company called Yamashita Iron Works was established in 1931 in the Nishiyodogawa ward in Osaka, about 20 km from Sakai. Shimano also started out (in 1921) called Shimano Iron Works and SunTour started out (in 1912) called Maeda Iron Works. In 1968 Yamashita Iron Works spun off Yamashita Machinery Co. Ltd. a maker of industrial handling equipment which seems to continue to have a serious business supplying production lines to Toyota amongst others. Yamashita Machinery Co. Ltd. also has a web site.

The strength of the first possibility is that the company definitely made bicycle components in the relevant period. The strength of the second possibility is that the company definitely had ‘Iron Works’ in its name.

Sun-Bow is vaguely interesting in that the brand is a rare example of a Japanese manufacturer producing cheap derivatives of the products of another Japanese manufacturer (SunTour in the case of the derailleur in this collection). In the early days, Japanese manufacturers often copied European designs, and latterly the Taiwanese, Chinese, Indians and finally the Europeans have copied Japanese designs, but it is unusual for the Japanese to copy other Japanese designs.

I have no solid information on dates, but I vaguely remember seeing a Sun-Bow on a no-name Japanese bike in about 1977.

Sun-Bow derailleur thumbnail

Sun-Bow 1977?

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