Make sure you correctly identify the dog. Remove yourself to a safe distance and get off your bike. Carefully and without attracting attention, follow the dog home. When the owner comes out to retrieve the dog the owner in the face with pepper spray. This is the important part, give the dog a treat. I like the buggy whip idea and shooting the owner in the buttock with a pellet gun appropriately pumped is also a strong deterrent. You shouldn't have to repeat the process but be ready to do so as some people just have a stupid streak. An over imaginative mind at work.