What jack to have onboard for roadside tire changes?

Actually, if you have a leveling system on your coach, use that. I normally do not recommend ever raising the real wheels off the ground, but I do know that it can be done. during the one rear tire blowout we have had, I called my emergence road service to come change it for me. I asked the service person "my jacks or yours", we used mine, then he put a jackstand under the axle for safety, and we lowered onto it. With a dual axle, I don't know. He said that he actually felt better about my jacks than his!