265/70R17 vs 285/70R17 Tires

[Jayson in Arizona]

OK guys I need some advice. I drive a 2013 Ram 1500 4x4 with the 3.6 v6. I have 3.21 gears and the factory anti spin rear differential. Currently I have a set of 285/70R17 All terrains on the truck but Im debating on if I should go back to the stock size 265/70R17 tires at this next set that i have coming up. I currently average about 17.5 MPG and with the stockers I got 19-20 average. I know the truck would run and perform more efficiently on the street with the stock size tires but my fear is how much performance would I lose off road? Do you guys think going back down to stock size tires would hurt my off road performance considerably or not much at all?

Thanks in advance!

 

[kurek]

Did you recalibrate your speedometer/odometer for the new tire size? If not, you've actually been getting around 18.2mpg (if you calculated 17.5 from an uncorrected odometer)

All terrains are always going to get worse MPG than lightweight all season tires no matter the size. If I was you I'd just calibrate the speedo and enjoy the slightly larger tire if you do actually take the thing off pavement.

Another alternative is 255/80R17 they fit fine - still needs the speedometer calibrated but they're tall/skinny so you don't take quite as much weight and aero penalty on the highway.

 

[Jayson in Arizona]

I did not recalibrate so that is an interesting and valuable point, thank you Kurek! That makes my decision easier but still I have to wonder is it even worth the 1 mpg loss for what I gain in offroad performance? I do take the truck offroad fairly often. Im conservative but it sees a great deal of sand and snow throughout the year.

Thanks!