jhong1986

Hi guys,

I have a 2018 Ford F150 2.7L Ecoboost Lariat. I love my truck a lot and when I picked up my truck, it came with 18" wheels and 30.5" tires. I used to get 24-26MPG driving 80-90MPH.

I just got new 20" Fuel Sledge wheels and 32.9" Tires with a 2" leveling kit. It looks awesome! I recently drove from Houston to Dallas and I reset my trip settings and after arriving in Dallas, I got 12.9MPG.

Please help me figure out why my mileage dropped so much! I just got my tuner in today and even when driving 80MPH+ I still get 13MPG. Is this normal?

Stever39

Less aerodynamics with the lift and heavier tire/rim combo.

Ricktwuhk

The first question anyone is going to ask you is what you changed as far as the tire size within the truck's systems. The truck thinks you have the original wheels and tires. That's what it is computing everything on...

Leveling your truck and putting on heavier wheels as well as bigger and heavier tires will have a very noticeable negative impact on your MPG.

If you did nothing, you can use a speedometer calibration calculator, easily found via Google, to computer the difference.

As to MPG, driving 80-90 mph and getting 24-26 mpg seems improbable.

jhong1986

I don't mind it dropped a few MPG like most of you guys mentioned but I did not expect to lose 13 MPG

Ricktwuhk

I suggest you read what I posted as far as how to determine what you're actually getting. You do understand the concept that a tire size change makes the readout of miles driven, and therefore MPG attained, inaccurate, right?

Stever39

Did you calibrate the truck for the new tire size?

Ricktwuhk

How many places did you post this?

gone postal

Your mileage is going to be off unless you adjusted for the new tires with the tuner.

That having been said, you're doing 80 MPH in a 5K pound brick. Your mileage is going to suffer.

Apples

You have increased both the tire's overall diameter (making your effective final drive ratio taller) and the wheel/tire assembly's total weight (requiring more torque, and therefore fuel consumption, to get them rolling from a dead stop).

Other than buying another set of wheels and tires, your have two things you might do to increase your fuel mileage:

1. Keep it under 80 MPH - your highway mileage will improve

2. Re-gear your differential(s) to a shorter ratio. Your taller tires have made your effective final drive ratio taller. Then there's the additional weight of each tire... you may have increased each tire's weight by 15 lbs! from the factory fitment...


Don't believe an engine tuner's claims of increased MPG in your situation; you need mechanical help. You also, as the others posting before me have mentioned, need to recalibrate your speedometer reading for the new tire size.

jhong1986

Sorry I meant to post it here. It has been a while since I have been on the forums again