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  1. #1
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    Deore XT M771 RD Rubber Boot Thing

    What's the black wrap around rubber boot thing for? It says Shimano on it and I can't find an explanation. It wraps around part of the RD and then stays closed on itself by pinching closed on a rubber post that's part of the same wrap around thing.

    I have older Deore XT RD's that don't have. The older ones have boots on the cable tie down but the newer one doesn't have these.

    Just curious, what is it and what is it for?

  2. #2
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    I'll kind of answer my own question. It's item number 6 on this pdf of a different RD. It's shown on this one but not the Deore XT breakdown. The thing doesn't really do anything IMO other than be an add on do-dad that says Shimano?

    http://cycle.shimano.com/media/techd...9830609149.pdf

  3. #3
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    My 2006 XT derailleur has it, it's broken, and the derailleur still works fine. No idea what it does, may be keeps mud out of somewhere?

  4. #4
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    It wraps around the knuckle section of the derailleur and helps alleviate noise if the derailleur hits the chainstay, try manually pushing the derailleur body up, and you should see the rubber pad contact the CS.

  5. #5
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    Quote Originally Posted by luffy
    It wraps around the knuckle section of the derailleur and helps alleviate noise if the derailleur hits the chainstay, try manually pushing the derailleur body up, and you should see the rubber pad contact the CS.
    It's exactly as Luffy says... Suspension bikes, like the FSR four bar design of Specialized can be particulary prone to having the derailleur bounce off the bottom of the chain stay. In my case, the S Works Enduro 2006 came with a similar (but more 'beefy' version) rubber bumper that you zip tied around the derailleur.

  6. #6
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    I don't see it. The only part of the dr that would hit my cs is the cage part around the top pulley. The part with the rubber thing wrapped around it would never hit it in any gear. Maybe the bike I have it on has a different cs angle or something but the boot thing would never touch the cs. It's looking like a non functional do-dad.

  7. #7
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    bang.jpg

    This isn't the best picture to illustrate it... I'm sure you can see in it though that the derailleur can 'bounce' off of the bottom pivot on the rear suspension.

    This is slightly exaggerated in the picture, because I'm running a short chain (It broke and I needed to run it short before replacing). Notice how with the FSR design, the pivot is dropped lower than the rear wheel axle (hence the need for the 'rubber'). You might well not have the problem, in which case it's a completely worthless bit of rubber (I don't have one installed on my Cove for example)

  8. #8
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    My rd is on a Jamis Coda Elite. This type bike application for the rd makes the rubber thing non essential and it will be banished from my bike.

    Thanks for the pic, it definetly makes sense on that bike.

  9. #9
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    You're welcome - enjoy the trails : )

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