They make some nice 1.5 tires nowadays, I have no idea if they might fit your rims. Can you still get those original size tires?
I found this on Sheldon Brown's page: "the Canadian 26 x 1 1/2 size-that's 571 mm."
650C: https://www.sheldonbrown.com/harris/tires/571.html
I found this on Sheldon Brown's page: "the Canadian 26 x 1 1/2 size-that's 571 mm."
650C: https://www.sheldonbrown.com/harris/tires/571.html