Grinding noise coming from cassette area.
I recently replaced the chain, chainrings and cassette on my bike due to high mileage. The rear derailleur is a 105.
I went from a 12-25 cassette to an 11-23 since I don't have any HUGE hills around here. I made sure the new chain had the same number of links as the old chain.
Anyhow, it all went nicely and I noticed a big improvement in smoothness and noise. However, it's been about 500 miles since then, and the rear end of the bike has developed a very annoying noise. It is sort of a grinding noise. Almost like when the derailleur is out of alignment and the chain is rubbing. It is constant when I pedal. No noise when I coast. I spent plenty of time adjusting the derailleur and even replaced both pulleys and the noise did not go away. I have checked chain routing and it's correct. I have spent HOURS watching the chain, gears, etc. and have not noticed anything obviously rubbing causing the noise.
I thought perhaps it was the bearings or something so I took off the rear wheel and put on another wheel that I have and the noise continues. I did notice that the cassette lock ring was sort of cracked or 'chewed up' when I removed it. I thought that was odd... I torqued it down to 40 N*m as specified.
Other details.. new Ultegra chain and cassette with a 105 derailleur...
Could the lock ring be causing this? If so, where can I get a new one? I saw one on Nashbar but it said only for 12t small cog, and my new cassette is 11t small cog..