Hookless rim - are those tires wire bead or folding? In the days of hookless rims, folding tires did not exist. They worked just fine with wire beaded tires. If your tires are folding, make sure the beads are seated exactly equally. (Spin the wheel with mounted tires and 20-40 psi and watch the little molded line on the sidewall just above the rim. Don't quit until you have no hops or dips in that line on both side.)