hey so back in the summer I switched my tires from the stock good years to bfg ko2 E range in factory size ( 275 65 r18 )so far I love the tires however I've noticed @ over 5000 miles with the new tires I've dropped from an average mpg of 18.3 to 15.7. I was expecting a bit of a drop but is 2.5 mpg normal? this is my first time running an AT tire and an E range, I run my air at 65psi. I put the tires on at 57k miles and the truck is closing in on 63k miles now do you think plugs could be a factor as well. the truck is stock other than tires as of now. as I said I was expecting to take a hit on the mpg but more in the lines of .5 to 1 mpg any input would be great thanks guys

 

I don't know if there is a "normal" loss of mileage with a tire change. I have heard from a relative that runs a fleet that he sees a 1-2 MPG drop going from factory P-metric tires to LT All-Terrain tires. Not sure if those are normally Load Range E or not.

Also, each tire has a slightly different weight and rolling resistance, so each brand and model would be a little different.

My take on this is that you are within the normal range, but that is just my gut feel.

 

Back in June 2015 I mounted a set of BFG Rugged Terrains which are P rated but still much heavier than the factory Hankooks. My truck came with the P235-17 tires and I upgraded to the P265 - 17 series. I lost about 1.5 MPG's overall. I'm much happier with the look and the way the truck feels. And now that winter blend fuel seems to b e upon us, I've seen even a bigger drop and I normally do this time of year.

 

Andrew, I put the exact same tire on my 2011 Ecoboost a few years ago and I lost 1-2 mpg on average. I also got two speeding tickets the next week after I got my tires. I checked my speedo with a gps after this and found at 60 on the speedo I was actually running 63. I had never checked it before this so I do not know if my speedo was off before the tires or not. You might want to check on this. Even with the mpg loss the heavier tire is well worth it when pulling a camper.

 

Good point Mr. Mcbeevee, the new tires may be slightly larger circumference, which would exxagerate any change in MPG.

 

I am in for a shock as I am upgrading to 285/65R20 KO2s. With my Livewire I can adjust the speedo to the new tire size but right now I am lucky to get 15 mpg with my 3.5eb.

 

wow sorry to here about your speeding tickets... I'll be checking to make sure my speedo isn't off as well. I'm glad to here I'm not the only who lost mpg I had assumed that because I stayed with the same size I wouldn't be affected so badly... I hear you on the towing two weeks after installing the tires I loaded my utility trailer up with 5500lbs of gravel for a 25 mile trip and other than the rear sag the felt way more solid than with with the SRAs.

 

I just recently put a set of KO2's (Factory Size) on my 2011 FX4 Supercab 5.0L and I noticed about a 1.5mpg drop overall. But it's nothing that isn't manageable. Truck will be paid off in a few months anyway, just means I'll have a lot more extra money to put towards gas haha.

 

lol yeah mine is paid off so it doesn't bother me in that way. I've never ran and LT tire before so I wasn't sure if a2.5 drop was normal or if there was a problem with the truck... I know it needs plugs and it's booked to go to ford next week to have a full 60k mile service done which includes plugs and wires... I'll report on if the tune up makes a difference with the truck... it kind of makes you wonder what the guys with lifts and 35-37s are getting

 

If I had to guess, I'd say 10 to 12 miles per gallon would be pretty normal for those running 35's to 37's. I wen't from averaging 18.5 mpg to about 17 mpg, just from switching to a more aggressive A/T tire. When you start getting into larger than factory size tires, that's when your going to start seeing a real drop in MPG.

 

so I sent the truck to ford for its 60000 mile service which includes new plugs. I told my advisor about the dip in mpg and they flashed the computer as well. I'm happy to report after 250 miles I'm averaging 17.5 mpg. I'll see where it levels off after this weekend and report back

 

I have a 2012 F150 S/C FX4 with Ecoboost with 67k miles, im currently averaging about 15.5 mpg according to the truck. With a 2.5in leveling lift and BFG KO2 in 34x12.50 and Fuel Full Blown 20in wheels.

I figure im closer to 17mpg then what the truck thinks.....but I don't drive a truck for fuel ecnomy. I just drive it and fill the tank when the gauge tells me too.