[oneperfectrun]

Originally Posted by rpmerf

https://tiresize.com/comparison/
https://spicerparts.com/calculators/...rpm-calculator

I see your tire size is closer to 28.9"
In the transmission calculator I got:
Ring & Pinion: 3.5
Tire Height: 28.9
Engine RPM: 2000
Transmission Gear Ratio: 0.696

Vehicle Speed: 70.62

If I change that to 3.73, I get 66.26, so you would be over 2K RPM at 70 mph. Played with it a bit, ~2100 RPM at 70 mph.

I measured my tires on two separate occasions. Just a tick under 28”. They are mounted on factory 8” rally wheels so I’m thinking they may be just a bit shorter with the wider wheels. A friend has his truck at my shop and his has same size tires on the factory steel wheels. There is a visible difference with the two sitting side by side.