Are you lowered? if so what lowering kit? i would run stock up front and 285/40 in the rear. The rear will be nice and meaty which imo looks good on a truck. This is what i ran because the sidewall heights are as close as you can get to match each other. 275/40 are shorter than stock so throws off the speedo and imo the sidewall is too thin leaving you with even more gap between the fender and tire...unless you are djm