Seem to have isolated a Grindy noise in drivetrain . Looks like the chain is over too far causing it too rub on the inner plate of the rear mech . The chain/ lower jockey wheel need to move out wards so that it runs in the centre of the cage . How do I do that ? I changed the mech hanger in case old one was bent but no dice .

Is the chain hitting the mech in a particular gear or is it all of them?

Edit: Reading your info again, are there any spacers by the side of the jockey wheel? I.e. is the jockey wheel centered in the cage?

More noticeable under load ie climbing . Not sure about spacers , will look tomorrow . Can’t think it’s that been fine up til now ?

sounds more like time for new jockey wheels … they sound fubar’d !

Odd, mech cage twisted?

Educated guess here, clutch type mech, probably an XT or similar with a cartridge bearing lower jockey wheel, and the wheel has shifted on it’s bearing. If so, the assembly can be removed, and the bearing pressed back into place, but it’s likely to go again.

Coatsey indeed XT with clutch , will check lower wheel later cheers . Why do you reckon it will go again though ?

a)because it’s done it once already, and b)because they have a lot of previous form for it. Based on no more than a hunch, it’s possibly to do with the extra load the clutch puts on them being combined with running p*ss-poor chainlines of modern bikes. Could also be a faulty batch, mind, but I prefer my theory 😉