if a dog is threatening i will get off my bike put my bike between me and the dog and tell him to go home.
If this is somewhere you go often, carry rocks (or golf balls) and throw them at the dog.
you have to change from prey to master; by standing and yelling at him he can't chase you any more.
It has also been said not to make direct eye contact with an aggressive dog, but i have done that and won, doesn't mean you will.



Reply With Quote
He's a golden mix, so not scary looking or anything, but he's part hound and has an aggressive sounding bark. Luckily, he's lame, so he can't really chase for too far and he came back pretty quickly. He's never done it since then, either. We have NO idea why he chose that cyclist to go after and I could just imagine that our dog was a contributor to someone on some forum somehwere complaining about country folk and loose dogs! 
There used to be a dog on my commute, fenced but did bark. I brought "cookies" and soon the bark changed from aggressive to friendly. 