Ok. Since Ive put on my new Raceface narrow wide there is a grouchy sound when pedalling. Its very similar to a front mech thats not quite tuned right and is trying to shift a wee bit. Ideas?

Chain/cassette are new (both 9speed).

Chainline looks good. Not used any spacers driveside only one non-driveside.

Is the chain too short? New cassettes make that pingy noise until they bed in

Not an sram chain and shimano cassette is it?

I have found that combo noisy in the past when they are new.

Hang on- yes. Posh Shimano XT cassette and a PG971 Sram. I normall buy cheapest both but Evans pricematched the cassette.

Mine was the same, new cassette, mech, skinny/fat and chain.

If was the low-gear limit-stop and b-tension on the mech which needed adjusting.