Never had a problem in the US as most places have leash laws so people have their dogs under control. Just don't ride to close to them just in case. Thailand is a whole different ball game. Out in the countryside the stray dogs just run wild all over the place and there are lots of them. They are usually in groups of 4-5. I've run into them all the time. It's more difficult if they are in front of you and see you coming as you are now entering "their" territory. One tactic I've found useful is that if they are in front of you just make a hard turn into their direction. Now they think you are coming after them. Usually they run off of the road and into the brush. They may give chase once you pass them so it's good to keep your speed up. If you are stopped and they are becoming menacing, just stoop down as if picking up a rock. That usually sends them on their way as many Thais throw rocks at them so when they see that they back off.