The Stovebolt Site Forums The Shop Area Engine Shop proper tire size?

I have two trucks, 51gmc, 6 lug (wish I had original wheels with clips and hubcaps...), 116" wheelbase, 4 speed. So it is 1/2 ton. I don't know what the stock tire size was on it? My 1949 GMC is a 125-1/4" wheel base, 6 lug, 4 speed, 248-I6, 1/2 ton. It has a GMC 100 on the sides of the hood. So anyway, I don't know what the original tire sizes were on these trucks. Top speed of the 51 GMC is about 45 mph. That is with my brother following me in the Pontiac. I think the 235/75/R15 tires I have on the truck are too small, causing it to seem lower geared/run slower, but more power on hills. Is it supposed to have 6.50-16 or 7.50-16 tires?? that would be a lot taller and may kill the power too much, I am in WV after all, hills are a concern. Any thoughts anyone? Thanks!

Your 1/2 tons probably came with 4 1/2" wheels that are designed for 6.00 or 6.50 x 16 tires. Anything wider will cause the sidewalls of the tires to flex too much and generate heat. 15 x 5 1/2 wheels were available for 7.00 or 7.50 x 15 tires were available for a heavy duty option. 45 to 55 mph is what these vehicles were designed to run.