1. Better late than never
My steering would have a noticeable detent in the middle. I also had bad vibration in the handle bars.
These bearings fixed both. I wish I would have replaced the headstock bearings a lot sooner. The stock ball bearings that cam on my 2006 zx6r are junk. These are tapered roller bearings and superior in every way.
Not the easiest to replace if you are not skilled. 6/10 on the skill level.