Worn but not worn out. Single chainring up front.

Can’t get it to index across the whole cassette, fine in the top 4-5 or bottom
3-4 but not all.

Any suggestions?

Cable tension.
Bent mech/hanger.

bent hanger.

Check the shifting is in sync, i.e when the chain is on the 1st sprocket, is the shifter actually in its first position, or is it in 2? Release cable tension to see if it will shift further, or count the clicks as you shift down the block.

Another vote for bend hanger. Thought that when I read the thread title.

As others have said it’s a bent mech hanger (more than likely 😉 ), i work in a bike shop and see this problem every week if not every day.

Bent hanger

Tired cable

Twisted mech

just to be different – possibly worn jockey wheel bushes. how much ‘rocking’ play is there in the upper jockey wheel? found this solved my probs once with a sora and once with an alivio.

100% bent hanger.

Valve/tyre logo alignment…..or the above.

Have you recently changed the Cable inners?

Cable clamped the wrong side of clamp screw.

Is the cable clamped tight enough?

Dounds daft but more than once I’ve been trying to index my gears but its proved impossible, only to realise the bolt that holds the cable to the mech isn’t tight enough. When shifting the cable slips slightly and goes loose, it kind of causes the effect you describe.

Worth checking before you fork out £15 on a little piece of metal

I had this hanger straight, new cable I was pulling my hair out, turned out the mech was stiff and wouldn’t extend the whole way out.

Could well be any of the above but (hijack) I experience the same on only one of my wheels and it’s neither of those things that I can find. Have run a new chain, new cassette and new rings but still get 2 middle gears jumping all over the place. Wheel runs true too. Odd.

Dodgy valve/logo feng shuei has damaged the hanger’s mojo.

Loose lockring on the cassette?

All the above or…
Really bad chainline from your single ring?

When do we get to hear the results?

I started an almost identical thread on this a couple of weeks ago, everyone said bent hanger so I took it to bencooper to have it straightened.

Turns out the angle screw just needed one more turn as the jockey wasn’t as close to the cassette as it could be 😳

When do we get to hear the results?

i’ll have a look tonight.

Also – if you fitted the cassette and it was in loose pieces, perhaps remove and refit checking all the spacing rings are aligned and any tabs on them are located in the cassette cogs correctly. That could lead to a change in the spacing between the cogs through the gears.

Might be worth popping into a shop that has that cassette to copy one on the shelf?

I had a simialr issue, I took the cable out and checked and oiled it – it looked fine but still the issue continued. Last night I replaced the cable inner and it fixed it. So lesson learned.. even if the cable inner looks completely fine it may be the issue.

Sorted. None of the above…

Git!

What was it then?

10 speed mech on a 9 speed shifter?

Stiff link.

How very odd that it would index on half the cassette at any given time.

I had a similar thing. Middle 4 or 5 were perfect, higher or lower just wouldn’t play.

From a stiff link? Normally, the smaller the sprocket, the worse it is due to the greater range of movement needed.