Clattering noise on some cogs with Record 12 mechanical and Cervelo S5.
Well, I bought the frameset like I usually do and moved the Record 12 mechanical group from my old Look 675 frame over to this. I had a local lbs do the assembly for me.
The problem I am having is that (mainly on the big ring) the chain makes this clacking noise but only on certain gears. Only yesterday I took it to a different lbs and we checked the hanger (it was a little bent from the factory), made sure the cassette lock ring was properly torqued, the limit screws were set properly and played with cable tension forever.
I noticed that when it was originally assembled, an additional extension bracket was installed between the hanger and the RD itself. When we removed it it became impossible to shift onto the smallest cog. This bracket is 6.45mm wide by the way and I think it works as a spacer, never seen anything like it before but then I’m no mechanic.
We put the bracket back and every shift is perfect but the clacking noise is terrible and it’s worse on the larger cogs. It also baffles me because it’s there on say the 19 but not the 18 and it comes back louder a cog or two down the cassette. Everything is very low mileage on this group; I ordered a new chain and ultralinks last night in case it’s the chain because it does have two of those sram quicklinks.
Is there anything special about installing Campy 12 speed on these frames? It’s a second gen S5 in case this helps at all. I don’t even want to ride the bike because of this noise 😌