I am coming up on 12,000 miles on the rear tire, it looks like plenty of groove left but the tire is worn a little flat in the center and when I lean the bike on that ridge the back end does a little dance plus I get a slight howling sound. The manual says change the tire at .080 tread depth I think, I don’t think I’m quite there yet but is it time to replace it or good few a few more miles?