275/65/20 is a 34.1" tire. With stock 20 inch wheels you already have 33" tires (275/60/20) so it's not that much of a difference. I leveled my truck before I put the 34's on because leveling was my primary concern to be able to get a plow on. I noticed that the 275/60/20 tires wore quickly, both stock and Falken Wildpeak AT3W, but the 34's have a much deeper tread so they will last longer. Obviously there's a mpg penalty.
[I][B][COLOR=slategray]2016 Big Horn Hemi 4x4 w/ 3.21 Limited Slip [/COLOR][/B][/I]
[COLOR=dimgray][B][I] Bilstein 5100 at 2.1", Timbren SES, Airlift 1000, 18" Magnaflow, AEM Dryflow, 34" Falken Wildpeak AT3W, H9/9011 Headlight Upgrade, [/I][/B][B][I]7'6 Fisher HT, Bullet bedliner[/I][/B]