Anyone know what it is? I cant find anything in the Shimano docs for it…

Anyone?

Just go for ‘tight’ tending towards ‘effing tight’.

The cassette lockring is 40 Nm so I reckon somewhere about there should be right…

“chuffin nora thats tight” It’s an allen key so just do it as tight as you can, your unlikely to get enough torque to strip it.

Once it starts hurting the palm of your hand works for me…

Its made of steel so is the hub insert so I just tighten hand tight with an allen key – i.e. as tight as you can with a std allen key.

http://www.cyclistno1.co.uk/features/maintenance/xt-hub-service.htm