new cassette, chain & gear cable but chain still skips a bit

[ABlipInContinuity]

The indexing is spot on. When downshifting to a smaller cog, the chain will skip a bit and then settle down. I'm thinking the spring in the rear mech is a bit tired. If I try pushing the derailleur cage forwards, the mech doesn't seem to resist the pressure applied as well as the other mechs on the geared bikes.

If i hold the main body of the rear mech firm, the cage has a bit more laterall play when compared to the other bikes.

Is this a reasonable conclusion? Is it possible to repair the mech?

Cheers
aBIC

[Biggsy]

Some mechs naturally have quite a lot of play but still shift OK.  It would have to be really bad to affect shifting.

First of all, I would experiment more with cable tension even if you do think the indexing is spot on already.  It might be possible to improve shifting to smaller cogs without compromising shifting the other way too much.  I reckon cable tension is most likely to be the problem because the cable has just been replaced.

If the chain doesn't have any stiff links (check), the chain and cassette is most likely to be fine, and the mech won't have suddenly deteriorated.  If the mech was faulty, it would have been shifting poorly with the previous chain and cassette too.

[ABlipInContinuity]

I have tweaked the cable tension to both extremes to try and cure the problem. There aren't any stiff links in the chain (just re-checked).

The cable inner moves freely through the cable outer.

The bike is eight speed. I've just shifted it from the fifth to the sixth cog. The derailleur moves straigh away, the chain drops onto the sixth cog with three quarters of a revolution of the rear wheel, then it skips back up onto the fifth cog and then drops back down to the sixth cog and then seems happy to stay there.

The upper most jockey wheel is making contact with the right hand side of the chain (when looking from the back to the front of the bike), if I slacken the cable any further it would be too far to the right.

Maybe i just need to get a bike shop to check the gear hanger alignment.

[phil d]

The indexing is spot on.

I don't think it is.  I would suggest about 1/8 turn of the tensioner inwards (clockwise).  If that doesn't do it, try another.  It sounds close, but not quite there.

I assume that you have the cable the correct side of the clamping bolt?  It was a problem with this that first brought me onto a cycling forum (the C+ one, years ago) when Biggsy put me right.

[Biggsy]

Gear hanger alignment won't be relevant if it was OK before the new parts were fitted, and the bike hasn't fallen or crashed since.

Don't worry about what the jockey wheel and cage and anything looks like, experiment (preferably whilst riding) to find what tension works best in real-world conditions.

[Biggsy]

ps. Any particular cable tension should only be unacceptable if shifting performance is unacceptable or if the chain is clattering against a neighbouring sprocket.  Nothing else matters.

The upper jockey wheel floats, so it sorts itself out in time.  You don't have to worry about the jockey wheels anyway.  They take such a light load.

[inc]

What is the condition of the cable guide under the bottom bracket, it doesn't take much friction for the cable to drag slightly, a new cable running in an old groove, maybe worth a look if the other suggestions don't sort it.