Located this site for determing tire "revolutions per mile" by entering tire size. At the top in the black bar enter your tire size it will give the revs per mile.
Just looking at any methods to save fuel especially on a road trip. For example:
P235/65R16 has 720 RPM
P235/80R16 has 655 RPM
Now I need a chart to figure how fuel would be saved with a 65 RPM difference on my RWD vehicle
https://tiresize.com/tiresizes/