40 psi is too low. Go by what it says on the sidewall of the tires. Use a Milton or Schrader gage to get accurate readings. My sense of feel tells me at least 65 psi but then again go by the Mfg. recommendation on the sidewall. I bounce between 17 and 18 mpg city/highway running 70 psi in my Michelins. I have a 98 12v and wish my milage was better.
40 psi is too low. Go by what it says on the sidewall of the tires. Use a Milton or Schrader gage to get accurate readings. My sense of feel tells me at least 65 psi but then again go by the Mfg. recommendation on the sidewall. I bounce between 17 and 18 mpg city/highway running 70 psi in my Michelins. I have a 98 12v and wish my milage was better.
No not really, I run 55-60ishThe Mfg. recommendation is for MAX LOAD, right?
Doesn't 65 psi make the truck ride stiff as a board?
Gotta love these guy's. Keep hope alive. You didn't say how much larger your aftermarket tank is to get the 800 per tank? Everyone on here knows it's impossible to get 26mpg... especially @ 75-80mph. Maybe you got a 4bt by accident in your rig. Could have been a factory mis-hap.
I think the 35's w/aggressive tread are your main culprit.
I notice I get better mileage when I set cruise to 65-70 as opposed to 80. 80 might get me there faster, but it does cause a noticeable hit on fuel mileage.