Looks like its starting to cup. Do you have any vibrations or wobble? Cupping seems to only be a problem with certain tires. My stock tires did that, and I started getting a high speed wobble. Once I changed the tire Hasnt happened since. That was on an 05 800 classic. If you arent having any issues yet, I would just keep an eye on it, other may say replace asap. If you dont ride year round, may consider replacing before your next riding season starts. You didnt say how many miles are on it, or the bike they are on.