If you want to take a bike like this out on the road you really need to make sure things are set up right... besides the rotafix the cog and lock ring will need red loctite and one should be running a brake.

My Peugeot has been rocking a suicide hub for well over 10,000 km with nary a problem and removing the last cog required the use of a torch and a few extra hands since it was so solidly affixed.