New cassette and chain , 3rd sprocket from the top of the cassette , changes onto it fine then as you put some ooof through the pedals the chain skips . This obviously isn’t very reassuring for my Crown Jewels ! I think the rear mech is getting “baggy” with loads of sideways play but it still changes ok . Nothing obvious cassette wise , the barrel adjuster on the shifter could do with replacing , it’s on a CX bike , are they the same as on an MTB shifter ? Seems I can get one end of the block changing ok and not the other but not both ? I’m probably going to start again new inner and outer and barrel adjuster , just a puzzle why it changes ok up to the 3rd cog works ok for a bit then decides to start going walkabout !

What cassette?

I’ve been going through this for a few months (old hardtail frame, 9 speed). First I changed the cable – no good. Then swapped wobbly old 2008 mech for one from the spares box – still bad. Drivetrain had over 3000km on it, so I put on the new cassette and chainrings I had in the box, which had been waiting for spring – no good.

Must be the shifter, right? It is/was an XT unit bought 18 months beforehand. Absolutely blasted it with WD40 and lube. Seemed to help at first but shifting went wonky again. Replaced it with a new Deore unit – STILL not right! Useable, but just not right.

Bought a hanger alignment tool last week, bent hanger back into place. OK in the garage, taking it out Sunday/Monday for a test…

Bent hanger.

Classic symptoms.

Will look at hanger , but to the ( untrained) eye everything looks in line ? Benpinnick not sure what cassette some low rent Road one I bought off my son ! It was brand new though .

I had to double check the thread title.

I have nothing to contribute to this thread.