Originally Posted by
Marlin
What you describe sounds exactly like the problem I have on an 11 tooth small cog. If I switch cassettes to one with a 12 tooth small cog, no problem. So I left the cassette with the 12 tooth on. I couldn't figure it out either. This was on a 9 speed system. The problem was with a SRAM cassette, the Shimano cassette with the 12 tooth small cog does not have the problem.
This may be a different problem. When using an 11 you must also use the special lockring for the 11. The chain will ride the lockring instead of engaging the cog properly if the normal lockring is used with an 11.