I completed my PhD almost a year ago. I had 3 advisers for my PhD research and I could say that all the three hardly had any idea what I was doing. During my PhD days, I used to write papers and include them as co-authors of the work. It was frustrating indeed. Much part of the work is still not published. I am looking forward to publish the same in reputed journals. I really do not want to include them as the co-authors of the work as they are no way involved in the work. Now that I am done with the PhD studies, will it be alright to send the papers with single author?
Authorship standards vary a lot between disciplines, but generally the hierarchical relationship between you and the other authors should be irrelevant. In other words including them before only because they were your supervisors was wrong* so is excluding them now only because you feel they have no leverage anymore.
You mention the reputation of the journals, this is not a relevant factor. It's true that some more reputable journals describe authorship criteria explicitly, something that lower-tier journals rarely do, but the expectations is always that the listed authors contributed to the presented work according to the customs of the field.
It's impossible for anyone not closely related to your personal situation to tell you if they deserve authorship or not. What can be said is that quite often do graduate students underestimate the scientific contribution of their supervisors.
Your only option is to discuss the matter with them. Do they actively ask to be co-authors? Have you told them that you think their contribution is not significant enough?
*I know that this still happens, in some fields too often. That's why I wrote should be and not is.