I have recently restored an early 80s Puch Austro-Daimler Pacifica with stock Belgian straight-sided rims. I used Vittoria Zaffario 1 1/4 tires (the ones the OP probably used also) inflated to 90#, as recommended. I have not ridden the bike a great deal (maybe 50 miles so far), but have not had any problems at all with blowouts or with the tires "jumping" the rim. I cleaned the inside of the rims very well and made sure there were no burrs or nicks, used new cloth rim strips, standard gauge Schrader valve tubes, and dusted the inside of the tires and the tubes liberally with talc before installing them. I checked to make sure the tire bead was seated well about three times while inflating the tires, and then ran them at 75# for a few blocks before inflating them to 90#. No problems so far.