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My cheap bike that I use to commute has been taking a lot of punishment (mostly from salt that's been used to melt the snow). I've been thinking about changing the rear derailleur (maybe not right now, but for the summer), but I'm not sure what replacement part to get. My bike has a 6 speed 14-28T cassette.

This is a picture of my derailleur. I think it's a direct mount, so I was thinking about substituting it with the Shimano TX-35 Rear Derailleur Direct Mount.

Rear derailleur

And this is the replacement part that I'm thinking of buying.

enter image description here

Would the replacement part work, or do I need one with a hanger?

Thank you very much everyone.

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  • What is the name of the new Shimano part? I can see it is Tourney but the exact part number? Does it have 6 speed also? All in all, the old and the new derailleurs look very much alike, apart from cosmetic changes. Commented Feb 6, 2018 at 9:35
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    Tourney is the lowest in the grade, and is the most forgiving. You can probably fit the new one and have it just work, after tweaking the cable length. Note that you probably want a new chain and new cassette too.
    – Criggie
    Commented Feb 6, 2018 at 10:36
  • The current derailleur is a RD-TY21. Would changing the cassette and chain be just because of current wear and tear? I know that you usually replace both chain and cassette at the same time since they kinda wear each other out, so that would be the reason right? Commented Feb 6, 2018 at 21:52

2 Answers 2

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The difference between direct mount and standard hanger mount is the location of the mounting screw. Your frame has the standard hanger, you need an additional piece between it and the derailleur. If you look for images of TX-35, most of them look like this: enter image description here

Note the piece that the pivot screws into, which in turn screws into the frame. If you screw the pivot directly to your frame, the derailleur will work very poorly.

Shimano derailleurs between 6 and 9 speeds (10 for road) have similar actuation ratios and movement limits, so they are compatible. It is not unusual for low end bikes to have derailleur from a higher series, even if it is intended for more speeds than the cassette and shifters have.

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  • Makes sense. According to some people, the derailleur actually has the angled bracket that you mentioned, it's just the picture on the ad that is wrong. It should work then. Thank you! Commented Feb 6, 2018 at 21:54
  • Looks like they are the exact same shot or rendering, but yours has the bracket erased afterwards.
    – ojs
    Commented Feb 7, 2018 at 19:13
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The Tourney RD TX-35 should work fine. All Tourney level derailleurs work with 6 and 7 speeds (sprocket spacing is the same). The 35 without the extra hanger tab looks much less cheap in my opinion.

I agree with suggestion made in comments to replace the cassette and chain at the same time.

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