Originally Posted by
Paramount1973
What if you doubled the rim tape on the Zac19 rims? Is it possible that it would help keep the tire bead up out of the valley? FWIW, I have a 26" wheel with a Zac19 rim and the 42mm Panaracer T-serv tire I mounted on it went right on without any problems.
I think the problem isn't exactly the valley, but definitely some detail in the way the bead of the tire meshes with the hook of the rim. I'm sure there is a way to fix this, adding just the right amount of material at just the right place on the rim, but it might not be as simple as an extra layer of tape.