11-speed, 5800 105 .... the bike is fine in the middle of the cassette, a little noisy in the lowest gears (two biggest cogs) and sounds terrible in the bottom (smallest) three or four cogs. The chain ring looks okay ..... I am a little surprised, because the bike was nearly silent until I cleaned the chain. I put on the clean chain and it seemed to skip a little and grind. I changed the chain for another used chain and it grinded. I bought a new chain but I don't want to put a new chain on old gear and chew it up if there is a problem.
I guess I need to look into buying a new cassette ... i will need one eventually anyway.
It is funny .... up until about 2017 i could build bikes for fun. Now the prices of everything have doubled, at least, and just maintaining my bikes is a financial drain.
Thanks for suggesting MTB gear .... I was thinking of buying new or old 105, but those are not my only options.