Replacing old tires / wheels on 1972 Safari LY
We recently went through this drill as the DOT numbers concluded that one tire on our 75 could possibly be original. The tires weren't cracking and held air okay. But the guidelines are the lifespan of a tire is 3-10 years depending who is talking and if the tires are subjected to UV or unweighted and pressure reduced when in storage.
Rims supposedly have a stamp on them to tell you their weight rating. I was unable to find any on my presumably original steel wheels which for now we're keeping (plus we have the original hubcaps).
A couple of sites quoted the size of the original 7x15s to be 27.88" diameter, 225/75-15 to be 28.1" diameter, and 205/75-15 to be 27.1" diameter.
I have visible damage to the lead edge of the wheel wells, so the replacement tires are 205s, trailer tires, load range C (1,820 pounds @ 50psi - sometimes referred to as 6 ply).
You might try pulling one off and looking at the other side.