I just added some pro comp rims and 33" pro comp mudd terrain tires. My mpg dropped from 18 or so to 12-13. The tires were at 35psi.....so I raised them to 50psi and my highway mpg jumped back up to 17.5 or so. Also,my cruise control couldnt hold the speed at 75mph with the tires at 35psi...without cutting off the overdrive every 30 seconds. I basically had to turn off the overdrive. once i raised the pressure to 50...everything was fine again.

I would lower the psi for off road but does anyone see a problem with 50psi in a tire that says max psi 65??

I am new to the bigger tire world and I know that 35psi is the norm.....but it sure seems to ride nicer at the higher psi.