I have a page in my tire blog that I try to keep up to date with links to various Load & Inflation tables. I think you will find that almost all tires follow the same numbers with the exception of a handful of Michelin 22.5 items. so if you can't find a chart from your tire brand you can use any of the others except Michelin. If anyone finds a broken link or error please let me know and I will do my best to fix the problem. RE how to do the calculations: Here is a worksheet from Br