Very few dogs I've encountered are good for more than 50 yards, before they poop out. If a dog gets too close, I raise my hand and pretend to throw something at the dog. A firm NO! is also helpful. I used to ride past a farm house that was within 25 feet of the road. There was always a fat little terrior sleeping at the front door. I would try to be as quiet as possible, but as soon as I got even with him, he would jump up and with his short legs spinning in mid-air, he could go from 0 to 15 mph in a split secord. But he was only good for about 10 yards. Haven't seen him lately. I think he died of a heart attack.