Try the old toe strap trick. Works every time. Get the bead started and when you get to the point where it won't go on the rim, tie on a toe strap tight at that spot then push the other side into the bead. The toe strap holds the bead for you so you can use both thumbs to roll the other side of the bead onto the rim.
If you don't have a toe strap a zip tie or shoe lace will work also.
--
Last edited by drlogik; 02-01-23 at 09:11 AM.