BFG KO2 vs OEM Dunlop MPG

[ZUKEYPR]

Wouldn't believe it if the wife and I both did the before and after test but our 2012 Taco dropped from 20 mpg on the OEM street tires to 13.1 immediately after changing to the same size new BFG KO2s. I expected a slight decrease but WOW.

 

[TurboMinivan]

Wouldn't believe it if the wife and I both did the before and after test but our 2012 Taco dropped from 20 mpg on the OEM street tires to 13.1 immediately after changing to the same size new BFG KO2s. I expected a slight decrease but WOW.

Okay, I guess I'll be the one to say it: either your calculations are way off, or else there are other forces at work here. There is no way on God's green earth that simply swapping from tire A to tire B in the same size will cut your observed fuel economy by 35%. Hell, you could fill the tires with concrete and still not drop your economy by that much.

 

[ZUKEYPR]

Exactly it's impossible but I'm telling you. We drove to Nampa and back the week prior to the swap and just got back from the same trip. Hell I get better mileage in my LJ on 35s"

 

[Marsh99]

Did you leave your tacoma in 4 wheel drive the whole time with the Ko2?

 

[ZUKEYPR]

Of course not. I'm not throwing any codes either

 

[cruiseroutfit]

Bizzare. 2nd gen 4.0 manual or auto? Even a built 2nd Gen with oversize tires and a bunch of extra payload (bumpers, etc) still gets 15+mpg. I can't imagine how sticking with the same size tire albeit different brand would have such an impact...

 

[Troop92]

Nampa, as in Nampa, ID? That's where I grew up, and my folks still live. Was there a headwind to/from? I've never done that drive without one, at least in one direction. Coming back to Utah two weeks ago, our Murano averaged 18 with the brutal headwind, and we usually see 22-23

 

[spencurai]

Same size on the sidewall does not mean same actual measured tire size. Worn out tires are smaller diameter than brand new tires. Tires are also different weights. Do a little research and measuring and you might find where your discrepancies come in. In the meantime you might want to check your tire pressures and up them 5 or so PSI.

 

[ZUKEYPR]

Yes I know there could be a ever so small height difference but not enough to throw it off that much. 2012 four door automatic. Fierce headwind going up, tailwind coming back. Worse mileage was coming back

 

[skeptic]

Something else is going on. Tires way under inflated, something.. I haven't seen that much drop even going to larger tires. Heck, my XJ dropped less than that going from completely stock to ~5.5" lift and 32" MTs.

I will say when we switch from regular all season tires to soft sticky Blizzaks on my wife's Legacy her mpg drops from mid 30's to high 20's. She calls them her marshmallow tires and you can feel the softness just driving around. Winter gas and weather could also be affecting things. I notice a good 10% mpg drop during winter months.

 

[LT.]

I would not argue your findings nor would I argue your math. But, I also tend to think there must be some outside force at work here as well. Enviromentals, under inflated tires, parking brake dragging, something. Perhaps it is something as simple as the fuel quality, dirty air filter, cloged fuel filter, or something else.

I use fuel mileage as a way to measure peak performance often since I do not have a dyno close by. I would not weigh so heavily on it. Something else is at work here I believe. Please keep the updates coming. I am looking at two sets of these tires myself.

Thank you.

LT.

 

[jeep-N-montero]

Winter fuel can make a difference, but not sure it is that substantial, our Mazda 3 drops about 4 mpg on winter fuel. If your truck doesn't require premium you can fill up with ethanol free gas at a number of places in the valley and get better mpg.

 

[ZUKEYPR]

Have anywhere on the southwest side that carries it? Worth trying

 

[SLC97SR5]

Have anywhere on the southwest side that carries it? Worth trying

http://pure-gas.org/index.jsp?stateprov=UT

 

[jeep-N-montero]

http://pure-gas.org/index.jsp?stateprov=UT

I had no idea some stations carry premium in the ethanol free, this is awesome and thanks for posting the link.

 

[cuban b]

I had a very similar thing happen to my MPG in my jeep commander a couple weeks ago. I'm assuming it's the winter gas blend. I can't bring myself to believe that tread pattern took away 5 or 6 miles per gallon. I'll have to try some ethanol free stuff and test it out.