In my experience, it depends on the dog's disposition, as well as my own. I'm not at all afraid of dogs, large or small. When I see a loose dog, I look at it, and start saying soothing things to it like "Good Boy" in a friendly tone of voice. Most dogs recognize this tone, wag their tails, and watch me pedal by.

But, it doesn't work with all dogs. I've been charged by pit bulls that were focused as a smart bomb, and completely oblivious to anything I was saying (not to disparage pit bulls as a breed...I once got surrounded by a pack of 8 of them, and all they wanted to do was lick my legs!).

Most of the time, if "Good Boy" doesn't work, yelling "No" when they get close does. But, there are enough exceptions that I keep the pepper spray handy just in case.