Anyone know the stock tire size for a 1956 F100?

If not, any idea how to find out?

 

If you cannot find the information elsewhere, and if you know:

Your Ring and Pinion Ratio
The tooth count on the Speedo Drive Gear (on the tranny output shaft)
The tooth count on the Speedo Driven Gear (on the tranny end of the cable)

You can calculate tire revs/mile thusly:

(Driven gear teeth x 1000) / (Drive gear teeth x R&P ratio) = tire revs per mile

You can then go to the tire rack (www.tirerack.com) and look for a tire that matches.

For reference a 215/75-15 is 750 revs/mile and a 235/75-15 is 720

 

My best guess would be 6.50 X 15 or 7.00 X 15.
7.00 was a popular replacement as it was available in 6 or 8 ply
For American vehicles, Radials and P-Metric sizes came many years after
1956.

 

I was guessing a 6.95x15.

 

I'm not 100 percent sure about a 1956 model, but I know for sure that the stock tires on a 1955 F100 were 6.00-16. I doubt it changed from 1955 to 1956. 1957 was a new body style and maybe it changed then. Prety much all half ton pickups in the late 1940s and early 1950s ran on 6.00-16 tires.