3

Direct mount or hanger mount?

Sooo, one glance at these photos will tell you why I'm asking this...

enter image description here

Ouch!

Needles to say, I need a new one and I'd like to know what I should be looking for. It's for a 21-speed mountain bike, if it's of any importance. I hope you can make out anything from this mangled mess.

  • Hit a rock/log/curb or cage went into spokes? – Argenti Apparatus Oct 12 '18 at 18:03
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    Yep, that sounds like the cage went into the spokes. When you set up the new one make sure to set the limit screws properly. Park tool has a great video on derailleur setup - it's easy to find via Google – Argenti Apparatus Oct 12 '18 at 18:59
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    I'd be wary of the chain too - its had some lateral forces applied and may be damaged or weakened because of this. If the mileage is getting up there, consider replacing chain and cassette anyway as part of normal maintenance. – Criggie Oct 12 '18 at 22:09
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    You'll also want to check all your spokes for breaks, or cuts/damage - its not impossible for them to break in the next few months due to starter damage. The wheel may even be out of true now because of the wrenching forces applied. – Criggie Oct 12 '18 at 22:11
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    Also check your limit screws carefully on the new mech - sounds like some extreme leg power on the climb has flexed the frame and allowed the derailleur cage to catch a spoke. You might have heard "tink tink tink" noises while riding, before this problem, and that was your warning. – Criggie Oct 12 '18 at 22:13
4

I think that the model you have is 'hanger mount' as it mounts to a derailleur hanger built into the frame rather than being attached by an axle nut.

There are many Tourney rear derailleur models. All Tourney rear derailleurs are 6 and 7 speed compatible. You'll want a model with a long cage (SGS postfix on the model number).

The RD-TX800, RD-TY500 or RD-TY300 models should be drop in replacements.

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    It looks a bit like the mangled type! :-D This said on the more serious side I'd look into the alignment of the hanger eye that is part of the rear drop-out. Other wise you might get problems with the indexing of the gear system. – Carel Oct 12 '18 at 18:00
  • Ok as you said, I have found numerous Shimano Tourney mechs, everything looks fine, 6/7/8 speed compatible, long cage, hanger type BUT, looking at the pictures of them I see that all of them have "SiS" printed on them instead of "SGS". Are these distinctions even related to one another? – Alex Oct 13 '18 at 18:55
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    SIS stands for Shimano Indexing System, nothing to do with cage length. – Argenti Apparatus Oct 13 '18 at 19:24
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    @carel good point about hanger potentially being bent. – Argenti Apparatus Oct 13 '18 at 19:25
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    @alex I can see from your first photo that the hanger does not look disastrously bent. If it's a little bent hangers on steel frames can be tweaked back in line. – Argenti Apparatus Oct 13 '18 at 20:12
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Direct mount. Appears the derailleur's mounting bolt threads into hole machined into frame design making out the drop out area too. There is no separate piece of metal IOW. Whether a part of the frame (as the case is here) or a secondary piece of machined metal that mates to the drop out area of the frame---both are termed derailleur hanger.

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