Most dogs are not friendly. Being attacked by dogs on a bicycle is very dangerous and can be fatal. Here is what happens when two sweet pitbull mixes attacked me:



Broken and crushed femur, cracked hip, damaged knee and a stroke resulted and three months of lost work. It cost their owners a lot of money. Here is another that got a face full of spray, does he look friendly and just wants to get petted?:



The safest thing to do is to not try and outrun them but to stop, dismount and place the bicycle between you and the four (or two) legged assailant and take whatever defensives measure you deem needed to ensure your safety. I now carry spray and if that fails I also have a .357 magnum and I make no apologies should I have to use it as a last resort to prevent being bitten. And no, spray does not stop all dogs. The dog above despite being sprayed several times pressed his attack thrusting his head through the frame and snapping at me. He only retreated when his owner yelled at him to the position I photoed him. Fortunately I did not have to use deadly force but it was getting there. I did call animal control and reported the incident and with the photo and a video I took the officer asked if I wanted them ticketed. I said no, just a warning would do.