Poor Fuel Economy on 265/70R17 Tires

[doug910]

Anyone having issues with poor fuel economy recently? I'm not sure if it's just me or not, but I'm really struggling to get anywhere near acceptable numbers. When I first got the truck, I was ecstatic that I was matching EPA numbers (and in some cases exceeding). After about 7 months of ownership (July 2019), I went up one tire size and got 265/70R17 Falken Wildpeaks. They're about 10 pounds heavier per corner than the stock Hankooks, and I noticed a fuel economy reduction as expected of about 2 mpg or so. Not a huge issue. Then winter came around and I noticed another drop in fuel economy. Winter blend and the cold in the Michigan certainly effect fuel economy so I wasn't too concerned. But now that it's warm, I've been expecting my fuel economy numbers to go up but they haven't. I'm still averaging about 15-16 mpg or so, barely getting 18-19 on the highway. Aside from the tires, my truck is completely stock and I don't have a heavy foot when I'm just driving around town. Truck is at 23,000 miles.

I'm wondering if other people are experiencing similar numbers? My main source of concern is that I definitely saw higher fuel economy numbers with the updated tires. I'm not asking to get EPA rated numbers and I know putting stock tires would help if I still had the tires. But if anyone else is running 265/70R17 tires, your feedback would be greatly appreciated!

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[JaysOnTheEDGE]

Have you re calibrated your speedometer for the larger tires? if not your calculations will be off since the odometer reading is off now.

 

[doug910]

Have you re calibrated your speedometer for the larger tires? if not your calculations will be off since the odometer reading is off now.

I looked into that, but it's only a 4% difference in circumference. Actual fuel economy is definitely better than displayed, but only by a few percent, and wouldn't cause a loss of 6 mpg or so imo

 

[Langwilliams]

I'm on the stock tires an my winter MPG sucked. Lately it's been low twenty's an my current tank is over 26 (some extra highway an off work this week). I was looking at those tires too, great price on Amazon but worried about the extra 10 pounds per tire.

 

[doug910]

I'm on the stock tires an my winter MPG sucked. Lately it's been low twenty's an my current tank is over 26 (some extra highway an off work this week). I was looking at those tires too, great price on Amazon but worried about the extra 10 pounds per tire.

I got mine on Amazon, if you catch them on sale, they're FANTASTIC value. I love every aspect about the tire except for fuel economy, which I don't necessarily think it's necessarily a fault of the brand. BFG KO2 weighs the same. If you get them in stock size, I think the increase in weight is only about 5 lb.

 

[AzScorpion]

I just posted this in the thread Report your MPG.

"This fill up I averaged 22 mpg. Was a 60/40 city/highway mix plus we were off road a few times too. I still don't understand how some are getting such bad mileage especially when they're stock. This was mostly flat (no mountains) driving but also was in 4x4 through the sandy washes. I'm not all that light on the gas and have a 2.5" level and 265/70/17's so there's some added weight there."

Now winters here are not as cold as yours but I did drop about 1 mpg during our winter but as you can see I'm right back up there now. This was also running the ac about 1/2 the tank as the past 4-5 days it's been over 100 out. I know the Wildpeaks are a heavy tire and I remember @Hounddog409 writing about this with his previous F150. I love these Nittos and can't complain at all for the aggressiveness you get with them but still maintain a very quiet ride and good gas mileage. I installed these and the level kit a month after buying my Ranger so my Fuelly app is pretty much based on this set up.

Something definitely isn't right, maybe bring it in to see if there's an injector problem? I know there were a few early ones that had this but getting 15-16 without any lift/level isn't right. Hopefully they can find something for you.

 

[Dick Richie]

9900 miles on my Ranger. I've had the Falken WildPeak 265/70/17 on for about one week. I'm seeing 16.3 city driving in Houston. I reset my trip #1 last fill up. I run 93 octane, usually Shell or Exxon. 2.5 level going on later this week. When I was working out of state FordPass app would display 400 to 420 miles distance on fill up. My numbers are similar. * I use sport mode in town*

 

[Frenchy]

I am here in the Colorado Rockies and i have STEEP grades to climb going to and from work. I live at 10,000ft, pass by 11,000ft and work at 9,000ft. I have the Old Man EMU lift with 265/70-17 Bridgestone Dueler AT Revo 3. When I got the tires and lift I lost about .5-1mpg on average. After that i got the Livernois tune(towing now available too) and the MPG came back and went up!!! I am averaging about 23 going to work and back and i did a trip the other day where I averaged around 27. My suggestion to you, get the Livernois tune!!!

 

[Ace Holliday]

Have you checked your air filter? 23,000 miles is not a lot but in certain conditions it is.

 

[Matsterious]

9900 miles on my Ranger. I've had the Falken WildPeak 265/70/17 on for about one week. I'm seeing 16.3 city driving in Houston. I reset my trip #1 last fill up. I run 93 octane, usually Shell or Exxon. 2.5 level going on later this week. When I was working out of state FordPass app would display 400 to 420 miles distance on fill up. My numbers are similar. * I use sport mode in town*

Hey, I'm just curious, why do you run 93 octane? Btw I'm in Houston also.

 

[Frenchy]

Hey, I'm just curious, why do you run 93 octane? Btw I'm in Houston also.

In Colorado I run 91 constantly. Why might you ask? Well to begin with the EcoBoost engine love premium fuel!! Also if you look in the owners manual it states that you can run 87 but for towing and/or better performance to use premium fuel(91-93). When I saw that I made the switch and noticed much better response and better MPG. Running 87 might be considered ok but for the benefit for you and your truck use premium fuel.

 

[Matsterious]

In Colorado I run 91 constantly. Why might you ask? Well to begin with the EcoBoost engine love premium fuel!! Also if you look in the owners manual it states that you can run 87 but for towing and/or better performance to use premium fuel(91-93). When I saw that I made the switch and noticed much better response and better MPG. Running 87 might be considered ok but for the benefit for you and your truck use premium fuel.

Thanks for the info. I'm definitely going to try this especially since gas is so cheap. I've been averaging 24/5 mpg (primarily highway miles) on 87 octane w/stock tires but I heard turbos like higher octane.

 

[Dick Richie]

I've viewed the dyno tunes. I believe it is the Livernois showing 93 octane run before the tune, and another pull with 93 and the tune. The software detects the octane rating and adjusts for it. If I remember correctly we gain about 25 hp on 93 vs 87. OAR / Octane Adjust Ratio. is a value the Ford ECU uses to determine the quality the fuel being used in the engine I'm sure someone will correct me if I'm wrong.

 

[Frenchy]

I've viewed the dyno tunes. I believe it is the Livernois showing 93 octane run before the tune, and another pull with 93 and the tune. The software detects the octane rating and adjusts for it. If I remember correctly we gain about 25 hp on 93 vs 87. I'm sure someone will correct me if I'm wrong.

I honestly dont know about the gain between the 87 and 93. How Livernois has it set up right now is simple. Low octane performance(87-89), high octane performance(91-93) and towing(87-93). I have used the high ovtane and it is very nice for power. I recently switched to the towing tune while still keeping the 91 octane and i like it more since the transmission doesnt hunt as much on hills therefore giving better consistency or better MPG as we might say. I also like Livernois over 5 Star since it will automatically adjust for altitude unlike 5 Star. With 5 Star you have to request the high altitude which I think is dumb since with todays technology it shouldn't be a problem to adjust with a computer on the fly.

 

[Dick Richie]

I honestly dont know about the gain between the 87 and 93. How Livernois has it set up right now is simple. Low octane performance(87-89), high octane performance(91-93) and towing(87-93). I have used the high ovtane and it is very nice for power. I recently switched to the towing tune while still keeping the 91 octane and i like it more since the transmission doesnt hunt as much on hills therefore giving better consistency or better MPG as we might say. I also like Livernois over 5 Star since it will automatically adjust for altitude unlike 5 Star. With 5 Star you have to request the high altitude which I think is dumb since with todays technology it shouldn't be a problem to adjust with a computer on the fly.

I'm debating 5 Star vs Livernois. 5 star claims 75 hp increase and I believe right at 90 ft lbs of torque

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