Midway through a 47-48 mile ride yesterday I started hearing a regular chain noise and thought I might have suddenly developed a stiff link. This didn't seem logical in the middle of a ride especially since it recurred at the same spot in the crank rotation rather than in time with the chain. Loose chainring bolt did cross my mind, but I didn't see how they couldn't have come loose so I kind of dismissed the idea. After quite a few miles I decided I really needed to figure this out so I looked down at my crank and, sure enough, at least one of the bolts seemed to stick out farther than the others. I pulled over to check and THREE of the bolts were so loose they might have fallen completely out in a few more miles. Another was somewhat loose, and one was still tight. Yikes! I tightened them all up and continued home. It was a little scary to see just how loose those bolts had gotten without my having realized it. So check those fasteners often just like all the books say!