The old 7.50x20, 8.25x20, etc can be found here:
https://www.stausaonline.com/tires/sta-super-transport-2/They also sell the military tread tires in those sizes and more for the 20 inch rim, but our rims are so narrow you’ll never be able to install an 11x20 for example. But there are tire highest and widths in these listings. Using the tire height and the online calculator on
www.4lo.com along with your gear ratio and speed, you can calculate rpm at that speed.
