My mom has a bank register from the year she got married and there is an entry for "4 tires - $78" I ran this through an inflation calculator and in today's dollars it is $781. I don't know if tire prices had normalized following WW II, but that seems pretty expensive. When I used to run 4 ply nylon bias tires on my 1964 Nova I was lucky if I got 11K miles out of them. Today I get 80K out of a set of tires that cost about $450. If you got 10K out of a set of $78 tires in 1949, you buy 8 sets to get to the mileage I get from today's tires. In today's dollars that is about $6250 for what I spend $450 for today. Doesn't even account for much greater performance and safety.