I think +35 is a safer bet than +40mm, I'm pretty nervous about fitment. We know a 285/70R17 K03 fits on a +35 and that's 11.5" section width. So on +40mm I'm pretty confident 32.8X10.7 and under will fit but not sure about anything bigger. 18" wheels give you the option of going with a narrower tire.for my lariat, i’m thinking +35 or higher. still mulling over 17 or 18 and to level or not.