DISRAELI GEARS

SY

SY main image SY main image SY main image

SY 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:

Three further pieces of relevant information are that:

  • The patents covering the Sun-Bow 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 the S.Y. derailleur.
  • 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.

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.


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 Sun-Bow - YA-100 label 1977?

see also Sun-Bow - YA-100 label 1977?

Sun-Bow YA-100 label thumbnail


Koyo Corporation - web site 2019

Koyo Corporation - web site 2019

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