Has any one fitted a Race Face Cinch crank ? just built a new bike & fitted the crank, straight forward though I’m unsure what you do with the little lock ring, is it to take up the lateral play, i.e slide it up against the BB and then tighten it up?? Help !!

Cheers & best wishes for the new year.

Yes you use it to preload the bearings slightly. Just tighten it up finger tight and nip up the bolt.