Has anyone considered replacing individual cassette cogs. I'm hearing some chain noise coming from my Campagnolo Chorus cassette when in the no. 19 cog and not any other cogs. I recently replaced the Campy Chorus chain. I know I'm mostly in the middle cassette range when riding and found Campagnolo 17-19-21 carrier assembly for about $47 available. A Campy Chorus 11 speed 12-27 cassette goes for about $100.