Derailleur doesn't "spring" enough

Sounds like the cable may be getting caught on something

BullGod said:

My rear DA derailleur doesn't seem to spring adequately - it seems as though it is too tightly screwed on, as if I shift from 39 to 53 the derailleur seems to stay in position, and not spring back to accomodate the slack in the chain.

For example, if I ride on 53 the derailleur seems way too far forward, and then if I click to drop onto the 39, the derailleur stays in place and the chain is totally slack.

I can correct this by loosening the derailleur attachment a little, but is this a proper solution? I'm also thinking of removing the derailleur and cleaning / lubing where it attaches. Would this help? Maybe there is sand in there?

Anyone had this and know what to do? I really hope the answer isn't "Let's go buy a new derailleur"....

BG

Take the rear derailleur apart, particularly the lower pivot, clean/lube/put back together. If that is daunting, go to a decent bike shop and have them do it.

I guess you're on about a Shimano model with a spring around the hanger bolt as I had exactly that same problem you describe. Thought I'd overtightened the bolt at first. I stripped it down, cleaned it up, and on re-assembly found that it's not that well sealed so filled it full of grease just to make it harder for anything to get it, also put a little blob of silcone sealant in the spring location hole, but feel that may have been going too far.

the action is clogged with dirt or the spring is broken.

BullGod said:

My rear DA derailleur doesn't seem to spring adequately - it seems as though it is too tightly screwed on, as if I shift from 39 to 53 the derailleur seems to stay in position, and not spring back to accomodate the slack in the chain.

For example, if I ride on 53 the derailleur seems way too far forward, and then if I click to drop onto the 39, the derailleur stays in place and the chain is totally slack.

I can correct this by loosening the derailleur attachment a little, but is this a proper solution? I'm also thinking of removing the derailleur and cleaning / lubing where it attaches. Would this help? Maybe there is sand in there?

Anyone had this and know what to do? I really hope the answer isn't "Let's go buy a new derailleur"....

BG

Did SOMEONE do some/any maintenance on the rear derailleur, recently?

FWIW. Several years ago, I replaced the plastic "shroud" that sits behind the C-clip on one of my XTR rear derailleurs (it must have been damaged ... I don't have a clue, now, why I was bothering!) with one I cannibalized from another Shimano rear derailleur that I had, and when I put the derailleur back on the bike, it exhibited the SAME problem which your DA rear derailleur currently has -- when it was tightened on the hanger, it wouldn't pivot.

That fraction of a millimeter CAN apparently make a difference ... unfortunately (for the moment), I don't recall if I scrounged around for another plastic "shroud" from off another Shimano rear derailleur OR possibly/simply ran a Flat file lightly across the plastic "shroud" (which I don't remember doing, so I probably "found" another).

Presuming NO ONE worked on the rear derailleur, just check the play between the plastic "shroud" & the C-clip ... run some floss between the two to "clean" it out ... and hopefully, that will allow your rear derailleur to pivot properly.