I just got the pulley in the mail today, and I'm a little confused. The 65mm measurement is from where to where? I measured the diameter of the ribbed section of the pulley and only came up with 59mm. What's going on here?

Overall, it looks pretty nice. How can I tell how worn the bearing is? I uploaded some pictures... looks like it was hardly used (what do you guys think)? Anything I should check for before installing it?