You know, an 11t will not slide all the way onto the freehub body. So you could probably torque it without even using the rest of the cassette.
For this reason you might need a thin spacer behind the cassette, which has already been suggested above, so you are actually torquing the cassette and not just the first cog.
John
Edit added: While a bit OT, I’m running a 14t 11 speed 1st position cog with an 8 speed setup. It appears to be designed to interlock with an 11 speed 2nd position cog and an 11t lockring is also required since it sits off the freehub body.
Last edited by 70sSanO; 09-24-21 at 08:32 PM.