Oh, yes, Barry,
A very long time ago, I had not the time nor the will to change the bearings myself.
So I had a BMW mechanic do the job. A few days after I got the bike back, this nut was broken (the large platter on the top had detached from the core ...) and it took me a lot of efforts to remove it even if broken.... So maybe some manual have a wrong figure printed into them ;-)