I'm 64 and been chased by countless dogs, but never been bitten. I use a variety of verbal techniques toward dogs, depending on their actions and breed. Just the other day I spotted a cattle dog hunkered down by a tree waiting to pounce. I gave a loud "Hey! I see you." He looked extremely disappointed and watched me ride by. I find most respond to a calm, stern voice. Especially if you slow down.
Only once did I fear getting bit and couldn't get away. So I dismounted and put the bike between me and the dog. He insisted at getting me, so I eventually pinned him down with the rear wheel. He got out in a few seconds, yet his demeanor changed from "I want you." to "I want away from you." Rode that same route for years and never saw him again.
I like dogs.