I have a vintage Shimano derailleur that I'm trying to identify, specifically to figure out which jockey wheel set is compatible as mine badly need replacing. The derailleur is marked "Shimano SIS" but doesn't otherwise seem to have a model number or other identifier. As far as I know the bike is a custom build done in the mid-to-late 1980s. I don't necessarily need to know the derailleur model if for instance all derailleurs from that period use the same jockey wheels. I've found a few photos online that match my derailleur, but unfortunately not with an accompanying model number... derailleur front derailleur reverse

  • Road or mountainbike?
    – DoNuT
    Commented Mar 2 at 16:26
  • 1
    @DoNuT Road bike.
    – Kyle
    Commented Mar 2 at 17:42

2 Answers 2


I think, by the period (85-89), speeds and the SIS label (indicating "Shimano Index Shifting"), you can narrow it down, it could be

enter image description here

  • Dura-Ace 7400 - 6/7/8-speed
  • 600 EX - 6-speed
  • Ultegra 600 (6400) - 7-speed

6/7/8-speed are the same chain, so pulley designs could be universal.

See also: https://en.wikipedia.org/wiki/Shimano#Road_groupsets

  • Great, thanks a lot. Forgot to mention it's a 6-speed, so that narrows it down a bit more.
    – Kyle
    Commented Mar 3 at 12:10

Mine seems to be the RD-L541-SS variant based on the catalogue page reproduced here. Apparently a MTB derailleur, despite being mounted on a road bike. But it was a custom build by the original owner, so who knows why they chose it...

  • Sure about the model number, though? RD-M531 gives me lots of results for a fairly modern late-2000s 9-speed Deore rear derailleur. Deore XT was Shimano's first MTB groupset but those were numbered M7xx from the start, for example the '87 6-speed group was M731....
    – DoNuT
    Commented Mar 3 at 18:12
  • @DoNuT I noticed the same. I think more accurately it's a L541, but see the catalogue page scan that I linked. Unless they misprinted the listing for the M531, then there's also a derailleur from the 80s with the same part number...
    – Kyle
    Commented Mar 4 at 8:03
  • Looks legit, I'm actually surprised, Shimano are usually pretty strict with their numbering and there is continuity from the 80s to present day in most groupsets. I wonder if this is an original '88 document because West Germany didn't exist anymore when a "new" RD-M531 came out (in 2008). #27 and #31 would be the (legacy) part numbers for the pulleys, then. That could even be a hint to the pulleys you need.
    – DoNuT
    Commented Mar 4 at 9:13

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