doc,
I didn't completely answer your question. My tires went from a diameter of 26" to 32". This is more than 20% bigger. The improvement in shifting was the result of making the tires bigger. The improvement in steering was the result of removing the wide squishy tires and replacing them with narrower and harder tires. I don't know the size of the original-in-1955 tires. The original wheels for a 1/2 ton truck are 15". I went with 16" specifically because I wanted to use a 235R85/16 tire. I wanted the tallest tires I could get, and it was the right thing to do.
Hope this helps.
LT
