Machka 

Here's what I do:

1. Talk to them in a calm human voice to help them recognize that I'm human and not a deer or something.

2. Play virtual fetch. I act like I've got a ball in my hand, "show" it to the dog, and then "throw" ... often the dog(s) will go running off in the direction they think the "ball" went.

3. Stop and get off the bicycle, standing with the bicycle between me and the dog. If there's more than one, this is a bit more risky, but it works very well with one dog.

4. Yell at the top of my lungs so the owner might be able to hear me.

And yes, what you describe with two dog is common. It's a method dogs (and wolves and coyotes) use to take down deer, etc. One dog attacks openly with the goal of steering the deer over into a place where the deer will be cornered. The other dog sneaks up behind to be in the right place to take down the deer. The obviously barking dog is usually not the one you have to worry about ... it's the silent dog. And yes, I have been in that situation.

In my case the silent dog was in the ditch and the noisy dog was herding me over toward the ditch with the goal that I would fall into the ditch. I realized what was going on and started screaming toward the farm house up the road (to no avail), and swerving my bicycle back and forth to get me away from the edge of the road. Through swerving I got in front of the herding dog .... and sprinted for a cross road which had a bit more traffic.

BTW - it does help to know your breeds. Around here we've got a lot of border collies. Border collies are very intelligent dogs and aren't out to hurt you ... they just want to herd you. That's what they are bred for ... herding. They see a lone cyclist and think that you've got to be herded. Talking to border collies and getting off the bicycle to talk to them works well for them because they are smart enough to realize that you're human when you separate yourself from that contraption you're on.

Other breeds may indeed be out to hurt you.