I ride bicycle and often have mostly the little yappers chasing after me and biting at my leg. Is there a whislte that will scare them away? Sometimes I get a mouthful of water from my water bottle and spray them but this is not handy.

How about one of those little air horns that work on a small bottle of compressed air?

Haven't tried it yet but I bought a whistle today. But it says you have to tune it for the dog. I can see me riding along on my bicycle, being chased and tuning a whistle.

Fill that water bottle with ammonia.