I have learned that the first couple of letters on a stamped Shimano part mean the part type e.g. FD - front derailleur, and the first digit indicates the series e.g.

M960 XTR/DCL 9s
M950 XTR 9s
M900 XTR 8s
M800 Saint 9s
M760 DeoreXT/DCL 9s
M750 DeoreXT 9s
M740 DeoreXT 8s
M700 DeoreXT 7s
M630 DeoreDX 7s
M580 DeoreLX/DCL 9s
M570 DeoreLX 9s
M560 DeoreLX 8s
M550 DeoreLX 7s
M520 Deore 9s
M510 Deore 8s

However, when I look at a couple of bikes, there is nothing similar:

  • FC-M191 is an Alivio crank arm, while the "1" should have indicated a Tourney
  • ST-EK70 and SL-M310 - those are both shifters, the first one with integrated brake lever. Why are the first two letters different? What is "EK"?
  • CS-HG30-8I - cogset marking - wtf!?

Ideally, I would appreciate a .pdf Shimano catalogue, the paper version of hich I have seen at the LBS. Alternatively, explaination about my listed parts would also be an answer.

  • The confusion is intentional, so you will not be able to compare components by price/quality. The bike manufacturers like this since you can't set two different brands side-by-side and compare model numbers -- there's always some difference, even if artificial. Commented Jun 25, 2013 at 11:22
  • @Daniel R Hicks , at the LSB they have a several hundred page catalogue with pictures. Do you think somethink similar could be available online? Also, why imprint numbers at all, if their goal is not to provide information?
    – Vorac
    Commented Jun 25, 2013 at 12:00
  • The ST-EK70 doesn't seem to exist. But the EF in an ST-EF60 means "EZ-Fire". As for some of the other confusion, they sometimes share items between groups, and also offer "non-series components" which aren't in a particular group. I guess it's an internal numbering system, which maybe outsiders aren't supposed to fully understand? Commented Jun 25, 2013 at 16:26

1 Answer 1


Not a full answer, but I can fill in one small blank for you - in the CS-HG30-8I, the HG refers to Hyper Glide - this is Shimano's name for multi-speed sprockets that are designed to allow smooth gear shifting.

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