With steel rims 46~ years old they've shown me it is time to replace them.
Long term parking means moisture collects on the downhill round rubber crevices and gets pretty deep down the side rings above the tires bead seat - freeze/thaw must really amplify this, be able to see a crescent fissure running for 5, 7, 10 inches as wide as they are deep - 1/8" is probable now or better.
I bead blasted and painted these wheels 6 or 8 years ago, was time then and surely really time to swap them out now.
Remember jumping from a D to E can cause mysterious rim failures with these old wheels, the above may be a very good clue to that.
15" nokians on 15 in rims... I'm with that, sure...
...but am secretly hoping someone flags a good deal away from 15" to bump up to 16" blah blah