Hi, Sorry if this is obvious but I just want to confirm before damaging anything -- am I looking at a self-extracting crank here? Is it a case of tightening what I think is a retaining ring and then using a hex key in the centre bolt to remove? I can see that the hex fitting is already quite rounded in places, so want to make sure I know what I'm dealing with so I don't break anything! Cheers in advance.