If you see someone riding down the road on their motorcycle with their dog riding next to them in the sidecar all geared up with leather vests, goggles, and motorcycle patches, your first impulse might be to worry that the dog will launch out of the sidecar and land on the road. However, most people who ride bikes with their furry companions have worked for months and months (if not years) to make sure that the personality and behavior of their dog is one that matches up with biking. They do not just take a dog and throw them on a bike. If you're thinking about biking with your large dog, that's something very important to remember.
To start getting your larger dogs used to riding in sidecars, take small trips around the neighborhood going very slowly. If they are calm enough and do not try to jump out, then you can take longer and longer trips until they are completely road ready. There are some safety precautions to utilize for dogs riding in the side car so they are not just sitting there without any form of restraints. However, you do not want to take a dog with you that could struggle so hard against these restraints that they hurt themselves trying to get out. This is why the beginning starter trips are so important.
If you are at all uncertain as the behavior of your pooch and whether or not they would be good on a motorcycle, then the rule of thumb is they probably wouldn't be. Just like all dogs can't be guide dogs or guard dogs, not all dogs can ride on the motorcycle. This is a crucial distinction to make before you ever consider letting your dog ride in the sidecar.