If you have a non every-day set-up, please make the following check before installing the drive:

- screw the grooved nut on the left side till the end of the thread and measure, if the distance between cone rings is at least 1mm shorter than the size of your bottom bracket shell. If not, the nut can come to the end of the thread and cause blocking of the entire drive. Very hard even to unscrew it!

- Check, if the self locking silver nut on the left side protrudes at least 2mm. If not, the industrial bearing on the left side isn't guided by the seat of the nut but only by the thread. The unit will have play as shown in I.6.

- The third photo shows a wrong installation: the self locking silver nut doesn't protrude. The whole drive has play (-> I.6.) and you can't adjust gearing play, as the nut doesn't protrude.