clicking sprocket every 2 rotations
 

Okay group mind:

New cassette and chain (chain installed about 3 weeks before cassette). SRAM PG-1070 10-spd cassette, 11-32 (11-12-13-15-17-19-22-25-28-32) with a SRAM 10-spd chain.

All is good except a light clicking noise when the chain is on the 6th sprocket (the 19). Running the crank in slow-motion in the workstand, I can see that the click occurs roughly every TWO rotations of the cassette. There's no noise on any other sprocket, and turning the rear derailleur adjuster barrel has no effect on the volume or frequency of the click. Click happens in both the small and large chainring. Click happens when pedaling under load as well as in the workstand. My inexpert eye does not see any flaws in the sprocket, though I don't know that I'd be able to tell given the irregular ramps and tooth shapes. And if it were a flaw in the sprocket, I'd expect to hear the click every rotation, not every two rotations.

Any ideas would be much appreciated.

Thanks!

---Mike

Stiff chain link?

Given that the click sound occur every two turns of the cassette, problem may lie in the chain. It might be a stiff link. Since you just installed the new chain, you can specifically check the link where you connect the chain (the master link as this is a Sram chain).

No idea - I would expect that if it was the chain it would take around 5 rotations as your chain is around 100 links long and the cog is 19 teeth. Ride it and the noise will go away. Otherwise try a new cassette or chain and see which one cures it.