[AT] Farmall F-12 Question

[LeRoy Price III]

Given the current events of my family, I began thinking of dad's stories.  
One of which
I can remember a bit and that was my first ride on a tractor.  He had a 
Farmall F-12 that
was bought second hand and used to plow the garden and other odd jobs.

Anyway, I remember him telling me that it had 40 inch rear tires but not 
spokes.  He said
that were cast rears. Was there ever and 40 inch cast rear option?

I think I might start looking for a F-12, I think his was a 1936.

LeRoy