I just put 4 - 275/55/20 Cooper Discoverer A/T 3 XLT Load Range E tires on my 2021 Big Horn because I tow a 7500# GVWR TT. With no load I running them with 50 psi and will pump them up to ~65 psi when I tow. They're stiffer than the OEM's but ride smooth and almost as quiet as the OEM Bridgestone Duelers. I've decided to replace the emergency spare with a Load Range E rated tire. My spare rim is an 8 X 18, so I needed to find an 18" tire with the same diameter. It turns out to be a 275/65R18 which has only a 0.63% larger diameter than the 275/55/20's. I've found a Corsa A/T 275/65R18 Load Range E tire at Discount Tire with a good rating for a cost of $211.53 which includes mounting. balancing, and all the taxes. I didn't want to buy an extra 20 inch rim and the 20 inch tire is quite a bit more expensive. This tire may never hit the ground, but it will give me peace of mind knowing it's there if needed.