Factory tires on my truck are 265/55/r20 Pirelli Scorpions. I don't love them. I think they look too "slim" and "streety" for a truck, always have. I'm getting close to 50k miles, so I decided to get some new Cooper Discoverer RTX tires, but a step up in size (LT265/65/r20) and with an "E" rating. This kind of tire comes on heavier duty trucks like 2500's and F250's. I expect about a 1.5" lift from the tires alone, and a much stiffer ride, which I won't mind. They'll help when towing my heavier car trailer and should get better wear, from what I've read. I have them installed next week.