What size tire would fit a 1968 Mercedes 250? My manual says 175 R 14, and when I bought the car it had 4- 185 R 14 tires on it. Old tires had 2 sets of numbers, but newer tires have 3 sets of numbers. I need to get new tires but I dont know what the middle number should be on a modern tire. Can anyone help? Thanks. My name is Ethan Tuke and I live in Reading, Pa.

 

middle number is the sidewall heigth basically. most cars now have a 40-45-50-60 sidewalls trucks are usually higher like 70 and up. smaller the number the smaller the side wall is . rougher ride better handling but easier blowouts and tire and rim damage.