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  1. #1
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    rear derailleur adjustment question...

    Newb question, could use some assistance...

    background:
    Drivetrain is a 3x9 Shimano. Shifters and derailleurs are deore, rear derailleur is a deore shadow, front derailleur is LX.

    Front derailleur seems fine.

    Rear derailleur: I've set the high and low limit by tightening until symptoms of over-tightening are apparent, and then backing off until no symptoms are present.

    But I'm still having some unresponsiveness when shifting. When I'm on the middle chainring, the chain is reluctant to shift inward (toward the spokes). It shifts to the outermost rear cogs no problem... but it doesn't shift inward (toward the spokes) quite so robustly. Any suggestions? I don't know much about the B-screw... is this the adjustment that needs to be made? Any tips to make this easy?

  2. #2
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    The limit screws need to be set just so that the derailleur will not go further than the large cog and the small cog, that is their function. The b-tension screw sets the distance that the top pulley wheel rests from the cogs. Your problem sounds like cable tension. Give the barrel adjuster, on your shifter, a half turn counter clockwise and see if that improves things.

  3. #3
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    cha-ching. money.

    Thanks. I guess loosening the barrel adjuster tightens the cable and makes the shifters index correctly?

    At any rate, thanks for the tip.

  4. #4
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    Please make sure that the limit screws are set correctly. I can't stress this enough. If the low one is not set properly your derailleur will go into the wheel and if the high one is not set the chain will jam between your frame and small cog.

  5. #5
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    yes, I can see the danger in a mis-adjustment. It is somewhat worrisome since I did end up tightening both limits screws and backing off the b-screw by a half turn. I've run it through the gamut on all three chainrings and it seems firmly... well, limited. these are the first adjustments I've made on this bike since I bought it a couple months ago and frankly I'm surprised that I was able to tighten the limit screws as much as i did before the "symptoms of over-tightening" were evident...

    again, thanks kindly for the tip. I think I will leave the bike on the rack for the evening and double check my adjustments in the morning before I ride.

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