If you do a search there are tons of posts that have links to charts to tell you this information. Like pacman55 mentioned make sure what the max size tires you will run before your regear. With a 4" lift I guess you will end up with 33's. Remember a Jeep is a Jeep and isn't built to speed down the freeway, 85 is way too fast for me in a Jeep.
"The problem with arguing with an idiot is others can't tell which one the idiot is"
Well if I do put 4.88 now with 31 how is it going to feel verses 4.56 . I just bought 5 new bfgs at. I think it looks great. But it would've nice to have the option of pitting 33 in the future. But not sure of how it would ride for now with the 31s with 4.88.