Toyo Open Country AT2 - MPG vs Stock for '1/2 ton' owners

He's probably referring to the AT2, and if he is that's not an overly aggressive tire. IMO an AT tire is ideal for a pickup - good in snow and good enough offroad in most cases, but you don't compromise too much on-road or with treadwear.

Very good tire, imo. I would guess it's heavier and has more rolling resistance than the stock tires so it might ding your mileage some, but it's a worthwhile trade.