I have a bell on my mountain bike, since I often encounter hikers on the trails. I also have a bell on one of my road bikes. It is technically required by law here, but I often ride in situations where there are oblivious riders. Of course, if they are wearing headphones, a bell doesn't really help.

Does anyone know where to find a bell with a good old-fashioned ring (not the simple ping) that will fit modern 31.8mm handlebars?

By the way, Peter Sagan apparently rides with a bell too, so it isn't Fredly any more.