they had a small 10 bolt came with 8.25-20's on them but they would be a direct swap out with the super duty's 10 lug 19.5's i was just going use the 7.50-20's 34.75"-36.25" as there the same width and only 2 or 3 inch's tall than the 8R19.5 square shoulder 8R19.5's measure 33.5"-34.25" depending on brand and tread depth 245/70R19.5's run 33.25"-33.75" 225/7019.5's are too short for any thing i got the 245 is the same width as the square shoulder 8R's. . . Fuel milage Not an issue truck see maybe 5000-7,500 miles a year and i burn premium leaded fuel. Power is the issue truck dose not pull much but when it dose it's heavy. I wanted to find my ideal speed then run the lowest gearing i could to maintain that speed safely I was told due to the shot torque band and wide horse power band i should have running around 2800-3000 rpm at ideal speed because at 2grand it don't have any horse power. I was told that you would alway's floored or you would alway's be down shifting to keep it rolling from my 9 year's of running this truck it burned more fuel lugging at 2300rpm than freely spinning 3,000rpm. it has 190hp@3600RPM it's only got 85hp@2,000rpm.... now the torque on the other hand 304TQ@1,600RPM the torque curve clime's fast fast haold's steady and start's dropping around 2,200-2,300rpm. now driving the thing it seem's pull good it 3,300rpm she's wasting fuel by 3,500 rpm.
so i thought 72MPH@3,000 was ideal cause i myself would mostly be running 65-68 with it. . .
