I found on page 86 of my owners manual a section on checking the "drive chain slider". Like so many other things when looking at them for the first time I'm not sure I'm seeing a wear limit line. I've adjusted the chain a couple of times (6500 miles on bike now) but never realized that this rubber chain guard/guide was a maintenance item. Has anyone had to have it replaced? Is the chain designed to "slide" on this piece continually when driving? I've always found it hard to measure 1 inch to 1.4 inches of slack on the bottom of the chain without pushing it into this "drive chain slider" when I'm where I think the center between the sprockets is, so I usually measure the slack towards the rear wheel to get away from the rubber guide/slider.