I'm almost 100% convinced to move up to 35x12.50R18 BFG MK2 tires on my 2004 F150. I have 3.73 gears. I am currently running 275/70R18 Maxxis Bighorns which measure out to 33.2" tall. I'm getting around 14mpg according to my front dash (I haven't figured it out on paper yet, but I will on these next couple of tanks). When traveling to Mississippi doing around 65 or so on average I get around 16-17mpg according to the front dash. What is everyone else getting once they moved from stockers or 33" tires to 35" tires? Also, if you added a programmer after the move to 35" tires what was the difference from 35" with no programmer and 35" with programmer. I'm looking at the evo programmer if I do ever get one.

 

From my 32" stocker's to 35's I lost about 1 to 2 mpg mainly in city driving. Highway driving at about 65 mph I can still get up to 18mpg with my Edge programmer. Starting and stopping with heavy tires take's it 's toll on the mileage.

 

when i traded my scorpions (about 32") to my KM2's (more like 34.2" if you measure)
I actually increased my gas mileage because i went from 20" rims to 17" rims.

I know it sounds wierd, but its true. So if you're worried about mileage you might as well step down to the 17's. The tires are way cheaper too. Plus the tires look bigger on smaller wheels.

bigger=better... at least thats what she said.

 

How does wheel size affect gas mileage? I wonder if your increase in mileage can be attributed to something else. For example, maybe the treads on your newer tires helped. Or maybe because you had newer tires, you focused more on keeping them properly inflated.

 

The thing I dont like about 17s is the look small, fat sidewall tires = ugly, Bigger rim with about 4 - 5" sidewall is fine, but not like a 17" with a 35, horrible look.