I currently have a 7 speed cassette, 7 speed derailleur and 7 speed shifter from Shimano. Unfortunately, my rear derailleur (Shimano Tourney) broke, so I want to replace it with something better. The problem I'm facing though is that I'm finding only 9 speed derailleurs that fit what I'm looking for and where I don't have to pay stupidly high shipping fees (I was looking at the Shimano Alivio line).

That's why I'm wondering if a 9 speed derailleur works with a 7 speed cassette and shifter. Would it work with the chain I have right now or does a derailleur only work with chains rated for the same amount of gears?

  • Have you tried sourcing 8-speed derailleur. Pretty sure that will work fine. – OraNob Sep 12 '16 at 15:27

Yes, all 9-speed Shimano rear derailers share the same actuation ratio as all Shimano 7-speed ones, except for pre-7700 Dura Ace.

I've never seen a 7-speed chain rub inside a 9-speed RD cage. If somehow that were an issue, an 8-speed chain would work fine.

| improve this answer | |
  • Theres basically 1/128" of width difference, and you need a bit more tolerance to have the thing work reliably. – Batman Sep 13 '16 at 4:23
  • I can verify this since I am running a 7 speed freewheel with an Alivio RD (9 speed) with a 7 speed chain on my commuter bike. – Mario Chapa Jan 24 '17 at 8:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.