I've got a set of 26 bars in a 25.4 stem, but I don't know if it's safe either. I used a pry bar to open up the clamp very slightly, slid the bars in, and then grabbed the two ends of the clamp with channel lock pliers to close it up a little so the holes would line up close enough to get the bolt through. It creaked for like a week or so, and I kept swearing I was going to stop riding it, but I never did and the noise went away...it's been months now. If someone knows firsthand of a failure resulting from this, though, I'd like to know.