Fisherguy

If you want the best mileage you need to keep the revs below 2000 rpm. 2200 will burn way more fuel than 1600 -1800.
35's did not hurt my milage or power but I have a stick, actually it improved things for me on the highway, the stick's OD is a little on the low side from the factory.

farbonciber

i really like my 295 with no leveling kit. better mileage, fills wheel wells, fits under the 5er. i'm buying the same tires next time.

Highway 4x4

If you have mods that make more HP then larger tires will not effect much but I am at stock 235hp. Towing 8k at 60mph at about 1600-1700rpm in OD with 265's. You say adding an inch of tire diameter (285's)will have no effect?

pronstar

Anytime you lose gear (via taller tires) you lose power to the ground.
The question is: How much? Enough to notice given the type of driving you do?

I went from 33s to 35, have factory 3.73s.
Driving empty, not much of a difference in power, just slightly lower RPM.

Pulling 11K lbs., I do notice a slight loss of power. But still have enough to spare.

If I was pulling significantly more weight, I'd consider re-gearing.

If you have 235 hp, then you're going to notice the effect of gearing/tires more than guys with more powerful trucks.