Originally Posted by brandonjansen
Typically a 285 is the widest tire you can fit on the stock rims without any rubbing. However some guys have gotten away with up to a 305. The problem is that each truck is built slightly differently so it's hard to fully judge exactly what will fit on each truck.
A 295/65/20 will fit no problem height wise with a leveling kit but you will most likely need 1/4" spacers to clear the width. I understand why people are against larger spacers (such as 1" or greater) but you shouldn't have any problems with 1/4" spacers. There's more than enough stud length to accommodate them.
Thanks Brandon! Where could I get spacers if I need them? And is there any way to measure before ordering the tires to check if I'll need spacers?