Chain slack on small chainring.
My chain goes slack when dropping down to the small chain ring and moving down the cassette. Chain is new and has right number of links in it. I suspect the rear derailier is at fault as I get no problems in the large chainring, so is it possible the spring on the rear mech is the culprit and the rear mech is not springing back when changing gear, I can get the tension of the chain right by pulling back on it slightly?
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Comments
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Are you sure the chain's the right length? Which method did you use to determine this?0
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Chain is right length as it has been alright for 4 months so I am misleading a little to say it is new.0
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In that case it sounds like your assumption is correct in that the rear mech is at fault. Springs do break, but you should whip the thing off and give it a damn good clean first. I have seen rear mechs with restricted movement because of a small stone jammed in the parallelogram; the same could conceivably apply to the fore / aft movement of the cage.
If the spring is indeed broken you should be able to get a replacement.0 -
There's also a screw on the rear mech that you can use to essentially tighten the chain tension.
However, if the problem occurred out of the blue, then something must have broken, unless you got some massive chain stretch in 4 months (which is unlikely but possible)0 -
New rear mech was the answer, thanks for the replies.0
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Did you just go for the simplest solution, or was the thing knackered beyond repair? (I know Shimano spares can sometimes be a nightmare to get hold of)0
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I did go for the simple solution although the spring in the mech was still intact, but I bought the rear mech second hand so could not vouch for how old or how servicable it was0