Don't give up on 15" too quickly

At least on early cars, OEM was 145/80-13, and there are two 15" sizes that are within 1% (that is, manufacturing tolerances) of that diameter: 155/60-15 and 185/50-15.

It's worth noting that the very popular 185/60-13 is a bit too small, while 195/60-13 and 165/70-13 are also within 1%. That hasn't stopped me from running 185/60R13... just live with the optimistic speedometer.

145/70-14, 175/60-14, and 205/50-14 are all within 1%, but I have no idea what the availability is.

All of this is contingent on me not having fat-fingered the spreadsheet