I want to covert my 7 speed to 9. Currently I have a Shimano 600 derailleur. What parts do I need to make this work?

  • 3
    Why? What do you hope to gain through this complicated and expensive modification? Jul 15 at 19:20
  • 1
    You might get more mileage out of buying a second bike, a used one. Either ride as-is, or use as a parts donor.
    – Criggie
    Jul 15 at 19:22
  • 1
    @Criggie unless you know what you are buying, used can be a minefield. I'm surprised it's recommended so much. The chain and cassette are wear parts anyway and could easily be near end-of-life on a used bike and easily missed if not inspected by a weather eye. There were many bargains historically but finding the right bike in the right fit for throwaway money is not the current scenario over most of the world!
    – JoeK
    Jul 15 at 20:04
  • 2
    @JoeK Title says "affordable" and a whole used bike can be had for low/no cost. Its a viable alternative with some caveats, but that's getting away on a tangent. Its also a source of parts when "modern" bike shops may no longer stock older generations.
    – Criggie
    Jul 15 at 20:11
  • @Criggie sure it is!
    – JoeK
    Jul 15 at 20:20

The community generally seems to advocate against upgrading your bike. I'm not sure why, it often makes alot more sense than buying new and more than buying used much of the time.

If your bike was originally equipped with Shimano 600 the likelyhood is that it's a good quality frame with other good components so it's probably worth upgrading if you love it.

If you wanty to upgrade to 9 speed, that's great. The transitions between gears are smoother and the jumps are smaller. You probably won't be able to extend the total range of gears by much though. current 9-speed shifters are Shimano Sora R3000 (or higher 3000-series) and route the gear and brake cables under the bar tape on drop bars so look alot neater. These are probably the most expensive purchase. You will also need a new rear wheel as yours will be one of the earlier 600 series groups if it was supplied as a 7-speed system from new. It is possible to replace the freehub body in some instances but this is not an easy route to go down.

You will also need a 9-speed cassette and chain. You will probably not be able to have a wider range than 11-28 on your 9-speed cassette with the existing 600 derailleur. All the other components will remain functional and are compatible.

Perhaps you should post some photos of your bike; you may gain more support.

  • 1
    It would be better if a comment was posted to improve the answer, rather than being an anonymous drive-by downvote.
    – Criggie
    Jul 15 at 20:23

Basically everything shifting related.

9 speed uses a narrower chain and a wider cassette so you’ll need: New shifters, new chain, new cassette, new rear derailleur, new chainrings. Your old front derailleur+shifter might work. New cables+cable housing will probably be necessary. It’s possible you need a new rear hub (could be cheaper to get a whole wheel) if your old hub uses a freewheel-style cassette instead of freehub.

Upgrading to 8 speed would be simpler, I think you’d only need a new shifter and new cassette (and possibly new rear hub).

  • 1
    Probably don't need new chainrings, otherwise agree.
    – Adam Rice
    Jul 15 at 16:10
  • 3
    Sorry, the new hub is a certainty, or at least a new freehub body. Even freehub-style 7-speed cassettes are narrower so 7-speed freehubs won't fit a 8-speed cassette ...unless the manufacturer of the bike made easy to upgrade and bundled a 8/9/10-speed hub with a 7-speed cassette by using a spacer. Such bundling is unlikely unless the bike was originally very old (when 7-speed was the second most expensive option) and expensive (a cheap bike surely won't have a more expensive wider hub).
    – juhist
    Jul 15 at 16:56
  • @AdamRice I'm always leery of saying it's safe to use a crankset or chainrings with a narrower-than-designed-for chain. Narrower chains can get into places a wider chain can't, and if a narrower chain can fit between chainrings or between the outer chainring and the crankarm and get wedged in tight, that could result in a dangerous lockup or failure of the drive train. If I were to use a crankset with a chain narrower than it's designed for, I'd carefully check that there was absolutely no way for the chain to get between the chainrings or between the chainrings and crankarm. Jul 15 at 17:26
  • Won't need the new deraillieur, the 600 will be fine.
    – JoeK
    Jul 15 at 17:31
  • Why new cables? Jul 16 at 7:20

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