Brand New Sram X1 Chain & Cassette Noise?!

Lozol

After measuring my chain to check for stretch I replaced it with a KMC X11 EL 11 speed chain. I also took my LBS's advice on that I could get away with just replacing the chain as I caught it early enough. After fitting the new chain it made a rubbing/grinding nose when pedaling at a certain speed so I took the bike in to ask for some help which they then said it needs a cassette, so I got one and now it is still making the same noise!!! It doesn't make the noise with the old chain and cassette or in the workstand, on when seated.

I recently had a new rear mech installed and the gears and well aligned and indexed. The chain is also the correct length as I measured it against the old one.

The only thing left to replace is the chain ring! Is it something that can be fixed or shall I try riding it out?

cooldad

Firstly, how do you know the mech is indexed - did you do it, or was it done by someone else? If so it may need adjusting as things change.

Measuring a chain against an old one is pointless, as the old one will be worn. You need to measure it properly.

If the old stuff works fine, something is wrong with the setup of the new stuff.