Unfortunately it's not so easy .. there are two kind of CK ISO front hub : the LD ( big body ) and the SD ( small body ) . You also need to know what generation they are ( see the laser printed serial number and go to the CK website ) , so You can know the correct conversion to order , but unfortunately the old generation' s spares are not produced anymore . The SD hub need also to buy a new clamp ring , specific for the 15 mm shaft , while on the LD the same clamp ring of the 20 mm shaft can be used .